DESIGN AND THERMAL ANALYSIS OF FIN BODY WITH CROSS SECTIONAL FINS
The Engine cylinder is one of the major automobile components, which is subjected to high temperature variations and thermal stresses. In order to cool the cylinder, fins are provided on the cylinder to increase the rate of heat transfer. By doing thermal analysis on the engine cylinder fins, it is helpful to know the heat dissipation inside the cylinder.
The principle implemented in this project is to increase the heat dissipation rate by using the invisible working fluid, nothing but air. We know that, by increasing the surface area we can increase the heat dissipation rate, so designing such a large complex engine is very difficult. The main purpose of using these cooling fins is to cool the engine cylinder by air.
The main aim of the project is to analyze the thermal properties by varying cooling fluid, material and fin geometries of cylinder fins.
Parametric models of cylinder with fins have been developed to predict the thermal behavior. The models are created by the geometry, rectangular, circular and arc type geometries. Cooling fluids used in this thesis is air, oil. The 3D modeling software used is SOLID WORKS.
Thermal analysis is done on the cylinder fins to determine variation in temperature distribution. The analysis is done using ANSYS. Transient thermal analysis determines temperatures and other thermal quantities that vary over time.
Internal combustion engine cooling uses either air or a liquid to remove the waste heat from an HYPERLINK "https://en.wikipedia.org/wiki/Internal_combustion_engine" o "Internal combustion engine" internal combustion engine. For small or special purpose engines, air cooling makes for a lightweight and relatively simple system. The more complex circulating liquid-cooled engines also ultimately reject waste heat to the air, but circulating liquid improves heat transfer from internal parts of the engine. Engines for watercraft may use open-loop cooling, but air and surface vehicles must recalculate a fixed volume of liquid.
HYPERLINK "https://en.wikipedia.org/wiki/Heat_engine" o "Heat engine" Heat engines generate mechanical power by extracting energy from heat flows, much as a HYPERLINK "https://en.wikipedia.org/wiki/Water_wheel" o "Water wheel" water wheel extracts mechanical power from a flow of mass falling through a distance. Engines are inefficient, so more heat energy enters the engine than comes out as mechanical power; the difference is HYPERLINK "https://en.wikipedia.org/wiki/Waste_heat" o "Waste heat" waste heat which must be removed. Internal combustion engines remove waste heat through cool intake air, hot exhaust gases, and explicit engine cooling.
Engines with higher efficiency have more energy leave as mechanical motion and less as waste heat. Some waste heat is essential: it guides heat through the engine, much as a water wheel works only if there is some exit velocity (energy) in the waste water to carry it away and make room for more water. Thus, all heat engines need cooling to operate.
Cooling is also needed because high temperatures damage engine materials and lubricants. Cooling becomes more important in when the climate becomes very hot. HYPERLINK "https://en.wikipedia.org/wiki/Internal_combustion_engine_cooling" l "cite_note-1" 1 Internal-combustion engines burn fuel hotter than the melting temperature of engine materials, and hot enough to set fire to lubricants. Engine cooling removes energy fast enough to keep temperatures low so the engine can survive.HYPERLINK "https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" o "Wikipedia:Citation needed"citation needed
Some high-efficiency engines run without explicit cooling and with only incidental heat loss, a design called HYPERLINK "https://en.wikipedia.org/wiki/Adiabatic_process" o "Adiabatic process" adiabatic. Such engines can achieve high efficiency but compromise power output, duty cycle, engine weight, durability, and emissions
Most internal combustion engines are HYPERLINK "https://en.wikipedia.org/wiki/Fluid" o "Fluid" fluid cooled using either air (a gaseous fluid) or a liquid coolant run through a heat exchanger ( HYPERLINK "https://en.wikipedia.org/wiki/Radiator_(engine_cooling)" o "Radiator (engine cooling)" radiator) cooled by air. Marine engines and some stationary engines have ready access to a large volume of water at a suitable temperature. The water may be used directly to cool the engine, but often has sediment, which can clog coolant passages, or chemicals, such as salt, that can chemically damage the engine. Thus, engine coolant may be run through a heat exchanger that is cooled by the body of water.
Most liquid-cooled engines use a mixture of water and chemicals such as HYPERLINK "https://en.wikipedia.org/wiki/Antifreeze" o "Antifreeze" antifreeze and rust inhibitors. The industry term for the antifreeze mixture is engine coolant. Some antifreezes use no water at all, instead using a liquid with different properties, such as HYPERLINK "https://en.wikipedia.org/wiki/Propylene_glycol" o "Propylene glycol" propylene glycol or a combination of propylene glycol and HYPERLINK "https://en.wikipedia.org/wiki/Ethylene_glycol" o "Ethylene glycol" ethylene glycol. Most "air-cooled" engines use some liquid oil cooling, to maintain acceptable temperatures for both critical engine parts and the oil itself. Most "liquid-cooled" engines use some air cooling, with the intake stroke of air cooling the combustion chamber. An exception is HYPERLINK "https://en.wikipedia.org/wiki/Wankel_engine" o "Wankel engine" Wankel engines, where some parts of the combustion chamber are never cooled by intake, requiring extra effort for successful operation.
There are many demands on a cooling system. One key requirement is to adequately serve the entire engine, as the whole engine fails if just one part overheats. Therefore, it is vital that the cooling system keep all parts at suitably low temperatures. Liquid-cooled engines are able to vary the size of their passageways through the engine block so that coolant flow may be tailored to the needs of each area. Locations with either high peak temperatures (narrow islands around the combustion chamber) or high heat flow (around exhaust ports) may require generous cooling. This reduces the occurrence of hot spots, which are more difficult to avoid with air cooling. Air-cooled engines may also vary their HYPERLINK "https://en.wikipedia.org/wiki/Cooling_capacity" o "Cooling capacity" cooling capacity by using more closely spaced cooling fins in that area, but this can make their manufacture difficult and expensive.
Only the fixed parts of the engine, such as the block and head, are cooled directly by the main coolant system. Moving parts such as the pistons, and to a lesser extent the crank and rods, must rely on the lubrication oil as a coolant, or to a very limited amount of conduction into the block and thence the main coolant. High performance engines frequently have additional oil, beyond the amount needed for lubrication, sprayed upwards onto the bottom of the piston just for extra cooling. Air-cooled motorcycles often rely heavily on oil-cooling in addition to air-cooling of the cylinder barrels.
Liquid-cooled engines usually have a circulation pump. The first engines relied on thermo-syphon cooling alone, where hot coolant left the top of the engine block and passed to the radiator, where it was cooled before returning to the bottom of the engine. Circulation was powered by convection alone.
Other demands include cost, weight, reliability, and durability of the cooling system itself.
Conductive heat transfer is proportional to the temperature difference between materials. If engine metal is at 250 °C and the air is at 20 °C, then there is a 230 °C temperature difference for cooling. An air-cooled engine uses all of this difference. In contrast, a liquid-cooled engine might dump heat from the engine to a liquid, heating the liquid to 135 °C (Water's standard boiling point of 100 °C can be exceeded as the cooling system is both pressurised, and uses a mixture with antifreeze) which is then cooled with 20 °C air. In each step, the liquid-cooled engine has half the temperature difference and so at first appears to need twice the cooling area.
However, properties of the coolant (water, oil, or air) also affect cooling. As example, comparing water and oil as coolants, one gram of oil can absorb about 55% of the heat for the same rise in temperature (called the HYPERLINK "https://en.wikipedia.org/wiki/Specific_heat_capacity" o "Specific heat capacity" specific heat capacity). Oil has about 90% the density of water, so a given volume of oil can absorb only about 50% of the energy of the same volume of water. The thermal conductivity of water is about 4 times that of oil, which can aid heat transfer. The viscosity of oil can be ten times greater than water, increasing the energy required to pump oil for cooling, and reducing the net power output of the engine.
Comparing air and water, air has vastly lower HYPERLINK "https://en.wikipedia.org/wiki/Heat_capacity" o "Heat capacity" heat capacity per gram and per volume (4000) and less than a tenth the conductivity, but also much lower HYPERLINK "https://en.wikipedia.org/wiki/Viscosity" o "Viscosity" viscosity (about 200 times lower: 17.4 × 10?6 Pa·s for air vs 8.94 × 10?4 Pa·s for water). Continuing the calculation from two paragraphs above, air cooling needs ten times of the surface area, therefore the fins, and air needs 2000 times the flow velocity and thus a recirculating air fan needs ten times the power of a recirculating water pump. Moving heat from the cylinder to a large surface area for air cooling can present problems such as difficulties manufacturing the shapes needed for good heat transfer and the space needed for free flow of a large volume of air. Water boils at about the same temperature desired for engine cooling. This has the advantage that it absorbs a great deal of energy with very little rise in temperature (called HYPERLINK "https://en.wikipedia.org/wiki/Heat_of_vaporization" o "Heat of vaporization" heat of vaporization), which is good for keeping things cool, especially for passing one stream of coolant over several hot objects and achieving uniform temperature. In contrast, passing air over several hot objects in series warms the air at each step, so the first may be over-cooled and the last under-cooled. However, once water boils, it is an insulator, leading to a sudden loss of cooling where steam bubbles form (for more, see HYPERLINK "https://en.wikipedia.org/wiki/Heat_transfer" o "Heat transfer" heat transfer). Steam may return to water as it mixes with other coolant, so an engine temperature gauge can indicate an acceptable temperature even though local temperatures are high enough that damage is being done.
An engine needs different temperatures. The inlet including the compressor of a turbo and in the inlet trumpets and the inlet valves need to be as cold as possible. A HYPERLINK "https://en.wikipedia.org/wiki/Heat_exchanger" o "Heat exchanger" countercurrent heat exchange with forced cooling air does the job. The cylinder-walls should not heat up the air before compression, but also not cool down the gas at the combustion. A compromise is a wall temperature of 90 °C. The viscosity of the oil is optimized for just this temperature. Any cooling of the exhaust and the turbine of the turbocharger reduces the amount of power available to the turbine, so the exhaust system is often insulated between engine and turbocharger to keep the exhaust gases as hot as possible.
The temperature of the cooling air may range from well below freezing to 50 °C. Further, while engines in long-haul boat or rail service may operate at a steady load, road vehicles often see widely varying and quickly varying load. Thus, the cooling system is designed to vary cooling so the engine is neither too hot nor too cold. Cooling system regulation includes adjustable baffles in the air flow (sometimes called 'shutters' and commonly run by a pneumatic 'shutterstat); a fan which operates either independently of the engine, such as an electric fan, or which has an adjustable clutch; a thermostatic valve or just 'thermostat' that can block the coolant flow when too cool. In addition, the motor, coolant, and heat exchanger have some heat capacity which smooths out temperature increase in short sprints. Some engine controls shut down an engine or limit it to half throttle if it overheats. Modern electronic engine controls adjust cooling based on throttle to anticipate a temperature rise, and limit engine power output to compensate for finite cooling.
Finally, other concerns may dominate cooling system design. As example, air is a relatively poor coolant, but air cooling systems are simple, and failure rates typically rise as the square of the number of failure points. Also, cooling capacity is reduced only slightly by small air coolant leaks. Where reliability is of utmost importance, as in aircraft, it may be a good trade-off to give up efficiency, longevity (interval between engine rebuilds), and quietness in order to achieve slightly higher reliability; the consequences of a broken airplane engine are so severe, even a slight increase in reliability is worth giving up other good properties to achieve it.
HYPERLINK "https://en.wikipedia.org/wiki/Air-cooled_engine" o "Air-cooled engine" Air-cooled and HYPERLINK "https://en.wikipedia.org/wiki/Liquid-cooled_engine" o "Liquid-cooled engine" liquid-cooled engines are both used commonly. Each principle has advantages and disadvantages, and particular applications may favor one over the other. For example, most HYPERLINK "https://en.wikipedia.org/wiki/Automobile" o "Automobile" cars and trucks use liquid-cooled engines, while many small HYPERLINK "https://en.wikipedia.org/wiki/Airplane" o "Airplane" airplane and low-cost engines are air-cooled.
Generalization difficultiesHYPERLINK "https://en.wikipedia.org/w/index.php?title=Internal_combustion_engine_cooling&action=edit§ion=3" o "Edit section: Generalization difficulties"edit
It is difficult to make generalizations about air-cooled and liquid-cooled engines. Air-cooled HYPERLINK "https://en.wikipedia.org/wiki/Deutz_AG" o "Deutz AG" Deutz HYPERLINK "https://en.wikipedia.org/wiki/Diesel_engine" o "Diesel engine" diesel engines are known HYPERLINK "https://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Words_to_watch" l "Unsupported_attributions" o "Wikipedia:Manual of Style/Words to watch" according to whom? for reliability even in extreme heat, and are often used in situations where the engine runs unattended for months at a time. HYPERLINK "https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" o "Wikipedia:Citation needed" citation needed
Similarly, it is usually desirable to minimize the number of heat transfer stages in order to maximize the temperature difference at each stage. However, HYPERLINK "https://en.wikipedia.org/wiki/Detroit_Diesel" o "Detroit Diesel" Detroit Diesel 2-stroke cycle engines commonly use oil cooled by water, with the water in turn cooled by air.HYPERLINK "https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" o "Wikipedia:Citation needed"citation needed
The HYPERLINK "https://en.wikipedia.org/wiki/Coolant" o "Coolant" coolant used in many liquid-cooled engines must be renewed periodically, and can freeze at ordinary temperatures thus causing permanent engine damage. Air-cooled engines do not require coolant service, and do not suffer engine damage from freezing, two commonly cited advantages for air-cooled engines. However, coolant based on HYPERLINK "https://en.wikipedia.org/wiki/Propylene_glycol" o "Propylene glycol" propylene glycol is liquid to -55 °C, colder than is encountered by many engines; shrinks slightly when it crystallizes, thus avoiding engine damage; and has a service life over 10,000 hours, essentially the lifetime of many engines.
It is usually more difficult to achieve either low emissions or low noise from an air-cooled engine, two more reasons most road vehicles use liquid-cooled engines. It is also often difficult to build large air-cooled engines, so nearly all air-cooled engines are under 500 HYPERLINK "https://en.wikipedia.org/wiki/Kilowatt" o "Kilowatt" kW (670 HYPERLINK "https://en.wikipedia.org/wiki/Horsepower" o "Horsepower" hp), whereas large liquid-cooled engines exceed 80 HYPERLINK "https://en.wikipedia.org/wiki/Megawatt" o "Megawatt" MW (107000 hp) ( HYPERLINK "https://en.wikipedia.org/wiki/W%C3%A4rtsil%C3%A4-Sulzer_RTA96-C" o "Wärtsilä-Sulzer RTA96-C" Wärtsilä-Sulzer RTA96-C 14-cylinder diesel).
Cars and trucks using direct air cooling (without an intermediate liquid) were built over a long period from the very beginning and ending with a small and generally unrecognized technical change. Before HYPERLINK "https://en.wikipedia.org/wiki/World_War_II" o "World War II" World War II, water-cooled cars and trucks routinely overheated while climbing mountain roads, creating geysers of boiling cooling water. This was considered normal, and at the time, most noted mountain roads had auto repair shops to minister to overheating engines.
ACS (Auto Club Suisse) maintains historical monuments to that era on the HYPERLINK "https://en.wikipedia.org/wiki/Susten_Pass" o "Susten Pass" Susten Pass where two radiator refill stations remain. These have instructions on a cast metal plaque and a spherical bottom watering can hanging next to a water spigot. The spherical bottom was intended to keep it from being set down and, therefore, be useless around the house, in spite of which it was stolen, as the picture shows.
During that period, European firms such as HYPERLINK "https://en.wikipedia.org/wiki/Magirus-Deutz" o "Magirus-Deutz" Magirus-Deutz built air-cooled diesel trucks, Porsche built air-cooled farm tractors,HYPERLINK "https://en.wikipedia.org/wiki/Internal_combustion_engine_cooling" l "cite_note-2"2 and HYPERLINK "https://en.wikipedia.org/wiki/Volkswagen_Beetle" o "Volkswagen Beetle" Volkswagen became famous with air-cooled passenger cars. In the United States, HYPERLINK "https://en.wikipedia.org/wiki/Franklin_(automobile)" o "Franklin (automobile)" Franklin built air-cooled engines.
For many years air cooling was favored for military applications as liquid cooling systems are more vulnerable to damage by HYPERLINK "https://en.wikipedia.org/wiki/Fragmentation_(weaponry)" o "Fragmentation (weaponry)" shrapnel.
The HYPERLINK "https://en.wikipedia.org/wiki/Czechoslovakia" o "Czechoslovakia" Czechoslovakia based company HYPERLINK "https://en.wikipedia.org/wiki/Tatra_(company)" o "Tatra (company)" Tatra is known for their large displacement air-cooled V8 car engines; Tatra engineer Julius Mackerle published a book on it. Air-cooled engines are better adapted to extremely cold and hot environmental weather temperatures: you can see air-cooled engines starting and running in freezing conditions that seized water-cooled engines and continue working when water-cooled ones start producing steam jets. Air-cooled engines have may be an advantage from a thermodynamic point of view due to higher operating temperature. The worst problem met in air-cooled aircraft engines was the so-called " HYPERLINK "https://en.wikipedia.org/wiki/Shock_cooling_(engines)" o "Shock cooling (engines)" Shock cooling", when the airplane entered in a dive after climbing or level flight with throttle open, with the engine under no load while the airplane dives generating less heat, and the flow of air that cools the engine is increased, a catastrophic engine failure may result as different parts of engine have different temperatures, and thus different thermal expansions. In such conditions, the engine may seize, and any sudden change or imbalance in the relation between heat produced by the engine and heat dissipated by cooling may result in an increased wear of engine, as a consequence also of thermal expansion differences between parts of engine, liquid-cooled engines having more stable and uniform working temperatures.
Main article: HYPERLINK "https://en.wikipedia.org/wiki/Radiator_(engine_cooling)" o "Radiator (engine cooling)" Radiator (engine cooling)
Today, most automotive and larger IC engines are liquid-cooled. HYPERLINK "https://en.wikipedia.org/wiki/Internal_combustion_engine_cooling" l "cite_note-3" 3 HYPERLINK "https://en.wikipedia.org/wiki/Internal_combustion_engine_cooling" l "cite_note-4" 4 HYPERLINK "https://en.wikipedia.org/wiki/Internal_combustion_engine_cooling" l "cite_note-5" 5
A fully closed IC engine cooling system
Open IC engine cooling system
Semiclosed IC engine cooling system
Liquid cooling is also employed in maritime vehicles (vessels, …). For vessels, the seawater itself is mostly used for cooling. In some cases, chemical coolants are also employed (in closed systems) or they are mixed with seawater cooling.
Transition from air cooling
The change of air cooling to liquid cooling occurred at the start of World War II when the US military needed reliable vehicles. The subject of boiling engines was addressed, researched, and a solution found. Previous HYPERLINK "https://en.wikipedia.org/wiki/Radiator_(engine_cooling)" o "Radiator (engine cooling)" radiators and HYPERLINK "https://en.wikipedia.org/wiki/Cylinder_block" o "Cylinder block" engine blocks were properly designed and survived durability tests, but used water pumps with a leaky HYPERLINK "https://en.wikipedia.org/wiki/Graphite" o "Graphite" graphite-lubricated "rope" seal ( HYPERLINK "https://en.wikipedia.org/wiki/Gland_(engineering)" o "Gland (engineering)" gland) on the pump shaft. The seal was inherited from steam engines, where water loss is accepted, since steam engines already expend large volumes of water. Because the pump seal leaked mainly when the pump was running and the engine was hot, the water loss evaporated inconspicuously, leaving at best a small rusty trace when the engine stopped and cooled, thereby not revealing significant water loss. Automobile HYPERLINK "https://en.wikipedia.org/wiki/Radiator" o "Radiator" radiators (or HYPERLINK "https://en.wikipedia.org/wiki/Heat_exchanger" o "Heat exchanger" heat exchangers) have an outlet that feeds cooled water to the engine and the engine has an outlet that feeds heated water to the top of the radiator. Water circulation is aided by a rotary pump that has only a slight effect, having to work over such a wide range of speeds that its impeller has only a minimal effect as a pump. While running, the leaking pump seal drained cooling water to a level where the pump could no longer return water to the top of the radiator, so water circulation ceased and water in the engine boiled. However, since water loss led to overheat and further water loss from boil-over, the original water loss was hidden.
After isolating the pump problem, cars and trucks built for the war effort (no civilian cars were built during that time) were equipped with carbon-seal water pumps that did not leak and caused no more geysers. Meanwhile, air cooling advanced in memory of boiling engines… even though boil-over was no longer a common problem. Air-cooled engines became popular throughout Europe. After the war, Volkswagen advertised in the USA as not boiling over, even though new water-cooled cars no longer boiled over, but these cars sold well. But as air quality awareness rose in the 1960s, and laws governing exhaust emissions were passed, unleaded gas replaced leaded gas and leaner fuel mixtures became the norm. Subaru chose liquid-cooling for their HYPERLINK "https://en.wikipedia.org/wiki/Subaru_EA_engine" o "Subaru EA engine" EA series (flat) engine when it was introduced in 1966
Low heat rejection engines
A special class of experimental prototype internal combustion piston engines have been developed over several decades with the goal of improving efficiency by reducing heat loss. HYPERLINK "https://en.wikipedia.org/wiki/Internal_combustion_engine_cooling" l "cite_note-8" 8 These engines are variously called adiabatic engines, due to better approximation of adiabatic expansion, low heat rejection engines, or high temperature engines. HYPERLINK "https://en.wikipedia.org/wiki/Internal_combustion_engine_cooling" l "cite_note-9" 9 They are generally diesel engines with combustion chamber parts lined with ceramic thermal barrier coatings. HYPERLINK "https://en.wikipedia.org/wiki/Internal_combustion_engine_cooling" l "cite_note-10" 10 Some make use of titanium pistons and other titanium parts due to its low thermal conductivityHYPERLINK "https://en.wikipedia.org/wiki/Internal_combustion_engine_cooling" l "cite_note-11"11 and mass. Some designs are able to eliminate the use of a cooling system and associated parasitic losses altogether. Developing lubricants able to withstand the higher temperatures involved has been a major barrier to commercialization.
We know that in case of Internal Combustion engines, combustion of air and fuel takes place inside the engine cylinder and hot gases are generated. The temperature of gases will be around 2300-2500°C. This is a very high temperature and may result into burning of oil film between the moving parts and may result it seizing or welding of same. So, this temperature must be reduced to about 150-200°C at which the engine will work most efficiently. Too much cooling is also not desirable since it reduces the thermal efficiency.
So, the object of cooling system is to keep the engine running at its most efficient operating temperature. It is to be noted that the engine is quite inefficient when it is cold and hence the cooling system is designed in such a way that it prevents cooling when the engine is warming up and till it attains to maximum efficient operating temperature, then it starts cooling. To avoid overheating, and the consequent ill effects, the heat transferred to an engine component (after a certain level) must be removed as quickly as possible and be conveyed to the atmosphere. It will be proper to say the cooling system as a temperature regulation system. It should be remembered that abstraction of heat from the working medium by way of cooling the engine component is a direct thermodynamic loss.
Natural Air Cooling
In normal cause, larger parts of an engine remain exposed to the atmospheric air. When the vehicles run, the air at certain relative velocity impinges upon the engine, and sweeps away its heat. The heat carried-away by the air is due to natural convection, therefore this method is known as natural air-cooling. Engines mounted on 2-wheelers are mostly cooled by natural air.
As the heat dissipation is a function of frontal cross-sectional area of the engine, therefore there exists a need to enlarge this area. An engine with enlarge area will becomes bulky and in turn will also reduce the power by weight ratio. Hence, as an alternative arrangement, fins are constructed to enhance the frontal cross-sectional area of the engine. Fins (or ribs) are sharp projections provided on the surfaces of cylinder block and cylinder head. They increase the outer contact area between a cylinder and the air. Fins are, generally, casted integrally with the cylinder. They may also be mounted on the cylinder.
Natural air cooling Fins:
A fin is a surface that extends from an object to increase the rate of heat transfer to or from the environment by increasing convection. The amount of conduction, convection, radiation of an object determines the amount of heat it transfers. Increasing the temperature difference between the object and the environment, increasing the convection heat transfer coefficient, or increasing the surface area of the object increases the heat transfer. Sometimes it is not economical or it is not feasible to change the first two options. Adding a fin to the object, however, increases the surface area and can sometimes be economical solution to heat transfer problems. Circumferential fins around the cylinder of a motor cycle engine and fins attached to condenser tubes of a refrigerator are a few familiar examples.
Fernando Illan simulated the heat transfer from cylinder to air of a two-stroke internal combustion finned engine. The cylinder body, cylinder head (both provided with fins), and piston have been numerically analyzed and optimized in order to minimize engine dimensions. The maximum temperature admissible at the hottest point of the engine has been adopted as the limiting condition. Starting from a zero-dimensional combustion model developed in previous works, the cooling system geometry of a two-stroke air cooled internal combustion engine has been optimized in this paper by reducing the total volume occupied by the engine. A total reduction of 20.15% has been achieved by reducing the total engine diameter D from 90.62 mm to 75.22 mm and by increasing the total height H from 125.72 mm to 146.47 mm aspect ratio varies from 1.39 to 1.95. In parallel with the total volume reduction, a slight increase in engine efficiency has been achieved. G. Babu and M. Lavakumar analyzed the thermal properties by varying geometry, material and thickness of cylinder fins.
The models were created by varying the geometry, rectangular, circular and curved shaped fins and also by varying thickness of the fins. Material used for manufacturing cylinder fin body was Aluminium Alloy 204 which hasthermal conductivity of 110-150W/mk and also using Aluminium alloy 6061 and Magnesium alloy which have higher thermal conductivities. They concluded that by reducing the thickness and also by changing the shape of the fin to curve shaped, the weight of the fin body reduces thereby increasing the efficiency.
The weight of the fin body is reduced when Magnesium alloy is used and using circular fin, material Aluminium alloy 6061 and thickness of 2.5mm is better since heat transfer rate is more and using circular fins the heat lost is more, efficiency and effectiveness is also more. J. Ajay Paul et.al. carried out Numerical Simulations to determine heat transfer characteristics of different fin parameters namely, number of fins, fin thickness at varying air velocities. A cylinder with a single fin mounted on it was tested experimentally. The numerical simulation of the same setup was done using CFD. Cylinders with fins of 4 mm and 6 mm thickness were simulated for 1, 3, 4 & 6 fin configurations.
They concluded that
1. When fin thickness was increased, the reduced gap between the fins resulted in swirls being created which helped in increasing the heat transfer.
2. Large number of fins with less thickness can be preferred in high speed vehicles than thick fins with less numbers as it helps inducing greater turbulence and hence higher heat transfer.
N. Phani Raja Rao et.al. analyzed the thermal properties by varying geometry, material and thickness of cylinder fins. Different material used for cylinder fin were Aluminium Alloy A204, Aluminium alloy 6061 and Magnesium alloy which have higher thermal conductivities and shown that by reducing the thickness and also by changing the shape of the fin to circular shaped, the weight of the fin body reduces thereby increasing the heat transfer rate and efficiency of the fin. The results shows, by using circular fin with material Aluminium Alloy 6061 is better since heat transfer rate, Efficiency and Effectiveness of the fin is more. Young Researchers, Central Tehran Branch, Islamic Azad University, Tehran, Iran has stated that heat transfer in a straight fin with a step change in thickness and variable thermal conductivity which is losing heat by convection to its surroundings is developed via differential transformation method (DTM) and variational iteration method (VIM). In this study, we compare DTM and VIM results, with those of homotopy perturbaion method (HPM) and an accurate numerical solution to verify the accuracy of the proposed methods. As an important result, it is depicted that the DTM results are more accurate in comparison with those obtained by VIM and HPM. After these verifications the effects of parameters such as thickness ration, ?, dimensionless fin semi thickness, ?, length ratio, ?, thermal conductivity parameter, ?, Biot number, Bi, on the temperature distribution are illustrated and explained.
COOLING SYSTEM OF IC ENGINES
Heat engines generate mechanical power by extracting energy from heat flows, much as a water wheel extracts mechanical power from a flow of mass falling through a distance. Engines are inefficient, so more heat energy enters the engine than comes out as mechanical power; the difference is waste heat which must be removed. Internal combustion engines remove waste heat through cool intake air, hot exhaust gases, and explicit engine cooling.
Engines with higher efficiency have more energy leave as mechanical motion and less as waste heat. Some waste heat is essential: it guides heat through the engine, much as a water wheel works only if there is some exit velocity (energy) in the waste water to carry it away and make room for more water. Thus, all heat engines need cooling to operate.
Cooling is also needed because high temperatures damage engine materials and lubricants. Internal-combustion engines burn fuel hotter than the melting temperature of engine materials, and hot enough to set fire to lubricants. Engine cooling removes energy fast enough to keep temperatures low so the engine can survive.
Some high-efficiency engines run without explicit cooling and with only accidental heat loss, a design called adiabatic. For example, 10,000 mile-per-gallon "cars" for the Shell economy challenge are insulated, both to transfer as much energy as possible from hot gases to mechanical motion, and to reduce reheat losses when restarting. Such engines can achieve high efficiency but compromise power output, duty cycle, engine weight, durability, and emissions.
1 Leung and Probert implemented the experimental study to examine the steady state natural convection for the horizontal based or vertical based vertical fins. They observe the effect of fin height and fin spacing at optimal level. The two fin having length of 10 mm and 17 mm. the trail can be taken with fin base temperature at 20oC / 40oC above the air temperature of environment. The result of trails conducted for fin length of 150mm, 9±0.5 to 9.5±0.5 mm value of optimum fin spacing for the vertical fin protuberant from the vertical base and upward base, respectively. Optimum fin spacing does not affect by base to ambient temperature and fin height. It is clearly observed by this study.
2 Leung, Probert and Shilston They observe the effect of fin length with varying from 250mm to 375mm on the steady state heat transfer rate and optimum fin separation of vertical fin with rectangular bulging from horizontal and vertical base has been examined experimentally. The 40oC ± 0.3 above that of ambient temperature can be used at constant base temperature.
3 Welling and Wooldridge Rectangular, finned, vertical surfaces are used to observe the effect of heat dissipation on so many appliances. In this experiments data display the result of different geometry of fins on free convection heat dissipation stimulated experimentally. The result deliver initial design data for particular temperature and optimal value of the ratio of height of fin to the distance between fins and also gives the variation according to the temperature.
4 Leung, Probert In this study steady state heat loss have been observed from rectangular fin array of 250 mm long, 3mm thick and 60mm perpendicular extending rectangular fins of duralumin and 250mm x 190mm vertical base have calculated. The base having uniform temperature range of 40oC to 80oC with ambient temperature 20oC. To observe the curve of heat loss rate versus fin separation of corresponding maxima respectively at 12mm and 38mm with ±1mm tolerance. Latter maxima leads the maximum heat transfer rate. The heat transfer rate of horizontal and vertical fin array of rectangular shape on vertical base of rectangular are equated at same temperature and same geometry with identical base, the vertical orientation fin gives more heat transfer rate than other.
5 Yüncü and Güvenc this paper deals with experimental study of rectangular fin having horizontal base in free convection heat exchange. A trial set-up was built up and calibrated, fin-arrays of 15 set and fin without base plate was tested in atmosphere. Fin spacing ranges from 6.2mm to 83mm, Fin height ranges from 6mm to 26mm. Base to ambient temperature difference have been vary analytically and individualistically with the power supply to the heater varying from 8W to 50W. To fixed the fin thickness of 3mm and Fin length of 100mm. Fin spacing, Fin height and base to ambient temperature difference has been observed clearly by conducting experimental program. It was found that the convection heat exchange rate of fins get highest value as function of fin height and fin spacing base to given ambient temperature difference. And also improvement of convection heat exchange rate of fin without base plate is powerfully dependent on the fin height and spacing and no. of fin. And correlation was developed for base plate without fin with the nondimensional parameter.
6 Xiaoling Yu et al. observe thermal performance of two type?s heat sink such as heat sink with plate fin and heat sink with plate pin fin. The plate pin fin heat sink was constructed by providing columnar pin fin in between plate fins. The thermal conductivity aluminium material is 202 W/mK is used for heat sinks. The 10 W of heat load is given to the base heat sink was heated uniformly and different wind velocities passes from the heat sink such as 6.5, 8.0, 10.0 and 12m/s separately. They have experiential that heat sink with plate pin fin gives more pressure drop and lesser thermal resistance than heat sinks with plate fin.
7 Raaid R. Jassem studied effect of perforation on heat transfer rate. They have taken five fins and provide different shape of perforation on fins such as circle, square, triangle, and hexagon. They found that the temperature drop is higher for perforated fins than that of solid fins and fins with triangular perforation gives higher heat transfer.
8 K. H. Dhanawade et al. studied the square and circular perforated fin arrays in forced convection. They varied size of perforation as 6mm, 8mm and 10mm and range of Reynolds number from 21 x10 4 to 8.7 x104.They observed that square perforated fin array gives more heat dissipation at low Reynolds no. & the circular perforated fin array performs better at high Reynolds number.
9 Md. Farhad Ismail et al., in this experiment, study was made to investigate the turbulent convection heat dissipation on plate of rectangular on over a plane surface. The extended surfaces were of many types of horizontal perforations like circular, rectangular, hexagonal cross sections. RANS based modified turbulence model is usage to determine the heat dissipation and fluid flow parameters. Reynolds number deliberated from 2000-5000 basis on the thickness of the fins. Shape of lateral perforation has major effects on the heat transfer behaviour of heat sinks below turbulent flow conditions. Rectangular perforated fins have the lowermost and solid fins getting greater no numb. Perforated fins of Hexagonal shape have the maximum fin helpfulness. Trilateral pierced fins have a deepest skin friction coefficient.
AIM OF THE PROJECT
The main aim of the project is to design cylinder with fins for a 150cc engine, by changing the thickness of the fins, changing the cooling fluid and to analyze the transient thermal properties of the fins. Analyzation is also done by varying the materials of fins. Present used material for cylinder fin body is Aluminum alloy 204 which has thermal conductivity of 110 – 150 w/mk.
Our aim is to change the material for fin body by analyzing the fin body with other materials and also by changing the thickness.
Geometry of fins – Rectangular
Thickness of fins – 3mm and 2.5mm
Materials – Aluminum Alloy A204, Aluminum Alloy 6061, Magnesium alloys.
Cooling Fluid – Air, Oil
STEPS INVOLVED IN THE PROJECT
TRANSIENT THERMAL ANALYSIS
For modeling of the fin body, we have used Pro-Engineer which is parametric 3D modeling software. For analysis we have used ANSYS, which is FEA software.
INTRODUCTION TO CAD
Computer-aided design (CAD) is the use of HYPERLINK "https://en.wikipedia.org/wiki/Computer_system" o "Computer system" computer systems (or HYPERLINK "https://en.wikipedia.org/wiki/Workstation" o "Workstation" workstations) to aid in the creation, modification, analysis, or optimization of a HYPERLINK "https://en.wikipedia.org/wiki/Design" o "Design" design. CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing. CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The term CADD (for Computer Aided Design and Drafting) is also used.
Its use in designing electronic systems is known as HYPERLINK "https://en.wikipedia.org/wiki/Electronic_design_automation" o "Electronic design automation" electronic design automation, or EDA. In HYPERLINK "https://en.wikipedia.org/wiki/Mechanical_design" o "Mechanical design" mechanical design it is known as HYPERLINK "https://en.wikipedia.org/w/index.php?title=Mechanical_design_automation&action=edit&redlink=1" o "Mechanical design automation (page does not exist)" mechanical design automation (MDA) or computer-aided drafting (CAD), which includes the process of creating a HYPERLINK "https://en.wikipedia.org/wiki/Technical_drawing" o "Technical drawing" technical drawing with the use of HYPERLINK "https://en.wikipedia.org/wiki/Computer_software" o "Computer software" computer software.
CAD software for mechanical design uses either vector-based graphics to depict the objects of traditional drafting, or may also produce HYPERLINK "https://en.wikipedia.org/wiki/Raster_graphics" o "Raster graphics" raster graphics showing the overall appearance of designed objects. However, it involves more than just shapes. As in the manual HYPERLINK "https://en.wiktionary.org/wiki/drafting" o "wikt:drafting" drafting of HYPERLINK "https://en.wikipedia.org/wiki/Technical_drawing" o "Technical drawing" technical and HYPERLINK "https://en.wikipedia.org/wiki/Engineering_drawing" o "Engineering drawing" engineering drawings, the output of CAD must convey information, such as HYPERLINK "https://en.wikipedia.org/wiki/Material" o "Material" materials, HYPERLINK "https://en.wikipedia.org/wiki/Manufacturing_process" o "Manufacturing process" processes, HYPERLINK "https://en.wikipedia.org/wiki/Dimension" o "Dimension" dimensions, and HYPERLINK "https://en.wikipedia.org/wiki/Engineering_tolerance" o "Engineering tolerance" tolerances, according to application-specific conventions.
CAD may be used to design curves and figures in HYPERLINK "https://en.wikipedia.org/wiki/2D_computer_graphics" o "2D computer graphics" two-dimensional (2D) space; or curves, surfaces, and solids in HYPERLINK "https://en.wikipedia.org/wiki/3D_computer_graphics" o "3D computer graphics" three-dimensional (3D) space.
CAD is an important HYPERLINK "https://en.wikipedia.org/wiki/Industrial_arts" o "Industrial arts" industrial art extensively used in many applications, including HYPERLINK "https://en.wikipedia.org/wiki/Automotive" o "Automotive" automotive, HYPERLINK "https://en.wikipedia.org/wiki/Shipbuilding" o "Shipbuilding" shipbuilding, and HYPERLINK "https://en.wikipedia.org/wiki/Aerospace" o "Aerospace" aerospace industries, industrial and HYPERLINK "https://en.wikipedia.org/wiki/Architectural_design" o "Architectural design" architectural design, HYPERLINK "https://en.wikipedia.org/wiki/Prosthesis" o "Prosthesis" prosthetics, and many more. CAD is also widely used to produce HYPERLINK "https://en.wikipedia.org/wiki/Computer_animation" o "Computer animation" computer animation for HYPERLINK "https://en.wikipedia.org/wiki/Special_effect" o "Special effect" special effects in movies, HYPERLINK "https://en.wikipedia.org/wiki/Advertising" o "Advertising" advertising and technical manuals, often called DCC HYPERLINK "https://en.wikipedia.org/wiki/Digital_content_creation" o "Digital content creation" digital content creation. The modern ubiquity and power of computers means that even perfume bottles and shampoo dispensers are designed using techniques unheard of by engineers of the 1960s. Because of its enormous economic importance, CAD has been a major driving force for research in HYPERLINK "https://en.wikipedia.org/wiki/Computational_geometry" o "Computational geometry" computational geometry, HYPERLINK "https://en.wikipedia.org/wiki/Computer_graphics" o "Computer graphics" computer graphics (both hardware and software), and HYPERLINK "https://en.wikipedia.org/wiki/Discrete_differential_geometry" o "Discrete differential geometry" discrete differential geometry.
INTRODUCTION TO CAD
Computer-aided layout (CAD), also known as computer-aided design and drafting (CADD), is the use of pc era for the tool of design and layout-documentation. Computer Aided Drafting describes the method of drafting with a laptop. CADD software software, or environments, affords the purchaser with input-system for the purpose of streamlining layout strategies; drafting, documentation, and manufacturing procedures. CADD output is frequently in the form of digital files for print or machining operations. The improvement of CADD-based absolutely software software is in direct correlation with the strategies it seeks to preserve coins; agency-based software program (manufacturing, manufacturing, and masses of others.) usually uses vector-based absolutely (linear) environments on the identical time as image-primarily based software program program makes use of raster-based (pixilated) environments.
CADD environments regularly contain more than surely shapes. As in the guide drafting of technical and engineering drawings, the output of CAD have to deliver records, which includes materials, processes, dimensions, and tolerances, steady with application-specific conventions. CAD may be used to format curves and figures in -dimensional (2D) space; or curves, surfaces, and solids in 3-dimensional (three-D) devices.
CAD is an vital commercial paintings substantially used in lots of applications, which includes car, shipbuilding, and aerospace industries, organisation and architectural format, prosthetics, and hundreds of greater. CAD is also widely used to provide laptop animation for pc photos in films, advertising and advertising and advertising and technical manuals. The modern ubiquity and strength of laptop systems manner that even fragrance bottles and shampoo dispensers are designed using strategies top notch through engineers of the Nineteen Sixties. Because of its awesome economic significance, CAD has been a number one riding pressure for research in computational geometry, computer snap shots (each hardware and software software software program), and discrete differential geometry.
The layout of geometric models for object shapes, particularly, is frequently called laptop-aided geometric layout (CAGD).
Current laptop-aided format software software packages variety from 2D vector-based drafting systems to 3-d solid and floor modelers. Modern CAD packages can also regularly allow rotations in 3 dimensions, permitting viewing of a designed object from any favored angle, even from the inner searching out. Some CAD software software is able to dynamic mathematic modeling, wherein case it may be marketed as CADD — computer-aided layout and drafting.
CAD is used within the layout of device and device and within the drafting and format of all styles of homes, from small residential kinds (homes) to the maximum essential industrial and company systems (hospitals and factories).
INTRODUCTION TO PRO/ENGINEER
Pro/ENGINEER Wildfire is the same old in 3-D product layout, offering corporation-leading productivity equipment that promote best practices in layout on the same time as making sure compliance collectively together with your enterprise and company requirements. Integrated Pro/ENGINEER CAD/CAM/CAE solutions let you layout quicker than ever, on the identical time as maximizing innovation and high-quality to in the long run create extraordinary products.
Customer requirements may also alternate and time pressures may additionally maintain to mount, however your product design goals live the equal – regardless of your mission's scope, you need the powerful, smooth-to-use, cheap solution that Pro/ENGINEER offers.
PRO/ENGINEER WILDFIRE BENEFITS
•Unsurpassed geometry advent abilities allow advanced product differentiation and manufacturability
•absolutely included programs allow you to increase the entirety from idea to production indoors one application
•automated propagation of format modifications to all downstream deliverables lets in you to layout with self perception
•complete digital simulation skills will let you improve product common universal overall performance and exceed product first-rate desires
•automated generation of associative tooling layout, meeting commands, and device code permit for max manufacturing performance
pro ENGINEER can be packaged in exceptional versions to suit your desires, from seasoned/ENGINEER basis XE, to advanced XE bundle and employer XE package, pro/ENGINEER basis XE package deal brings together a huge base of functionality. From sturdy component modeling to advanced surfacing, effective meeting modeling and simulation, your dreams may be met with this scalable answer. Flex3C and Flex gain construct on this base providing prolonged functionality of your deciding on.
MODULES IN CREO
INTRODUCTION TO FINITE ELEMENT METHOD
Finite Element Method (FEM) is also called as Finite Element Analysis (FEA). Finite Element Method is a basic analysis technique for resolving and substituting complicated problems by simpler ones, obtaining approximate solutions Finite element method being a flexible tool is used in various industries to solve several practical engineering problems. In finite element method it is feasible to generate the relative results.
In the present day, finite element method is one of the most effective and widely used tools. By doing more computational analysis the approximate solution can be improved or refined in Finite element method. In Finite element method, matrices play an important role in handling large number of equations. The procedure for FEM is a Variation approach where this concept has contributed substantially in formulating the method.
FEM/FEA helps in evaluating complicated structures in a system during the planning stage. The strength and design of the model can be improved with the help of computers and FEA which justifies the cost of the analysis. FEA has prominently increased the design of the structures that were built many years ago.
4.6 General Description of FEM:
To acquire a solution for a continuum problem by FEM, the procedure follows an orderly step by step process. The step- by step procedure is as follows:
1. Discretization of the Structure: The first step involves dividing the structure into elements. Therefore suitable finite element should be used to model the structure.
2. Selection of a proper interpolation or displacement model: Since the displacement solution is not known exactly for a complex structure under any given load, we assume an approximate solution. The assumed solution must be simple and should satisfy the convergence requirements. In general, interpolation or displacement model should be in polynomial form.
3. Derivation of element stiffness matrices and load vector: From the second step, stiffness matrix k^ (e) and load vector P^ (e) of element e is solved from either equilibrium conditions or variation principle.
4. Assemblage of element equations to obtain the overall equilibrium equation: Since the structure is divided into several finite elements, load vector and individual element stiffness matrices are arranged in a suitable manner. From this, the overall equilibrium equation is formulated as
K? = P
Where k = assembled stiffness matrix.
? = vector of nodal displacement.
P = vector of nodal forces for the complete structure.
4.7 Computation of element strains and stresses:
Since ? is known, element strain and stress are computed using necessary equations.
4.8 Engineering Applications of Finite Element Method:
Initially FEM method was used for only structural mechanics problems but over the years researchers have successfully applied it to various engineering problems. It has been validated that this method can be used for other numerical solution of ordinary and partial differential equations.
The finite element method is applicable to three categories of boundary value problems:
Equilibrium or Steady State or Time-Independent problems
Eigen value problems
Propagation or transient problems
4.9 Various applications of FEM:
Civil Engineering Structures
Hydraulic and Water Resource Engineering
Electrical Machines and Electromagnetic
4.10 Advantages of FEA/FEM:
Non-linear problems are easily solved.
Several types of problems can be solved with easy formulation.
Reduces the costs in the development of new products.
Improves the quality of the end product.
Life of the product is increased.
Rapid development of new products
High product reliability.
Product fabrication process is enhanced.
4.11 Disadvantages of FEA/FEM:
Extreme aspect ratios can cause problems.
Not well suited for open region problems.
4.12 ANSYS Software:
ANSYS is an Engineering Simulation Software (computer aided Engineering). Its tools cover Thermal, Static, Dynamic, and Fatigue finite element analysis along with other tools all designed to help with the development of the product. The company was founded in 1970 by Dr. HYPERLINK "http://en.wikipedia.org/wiki/John_A._Swanson" o "John A. Swanson" John A. Swanson as Swanson Analysis Systems, Inc. HYPERLINK "http://en.wikipedia.org/wiki/SASI" o "SASI" SASI. Its primary purpose was to develop and market HYPERLINK "http://en.wikipedia.org/wiki/Finite_element_analysis" o "Finite element analysis" finite element analysis software for structural physics that could simulate static (stationary), dynamic (moving) and heat transfer (thermal) problems. SASI developed its business in parallel with the growth in computer technology and engineering needs. The company grew by 10 percent to 20 percent each year, and in 1994 it was sold. The new owners took SASI’s leading software, called ANSYS, as their flagship product and designated ANSYS, Inc. as the new company name.
4.13 Benefits of ANSYS:
The ANSYS advantage and benefits of using a modular simulation system in the design process are well documented. According to HYPERLINK ;http://www.nafems.org/events/nafems/2007/SDDFindings/; studies performed by the Aberdeen Group, best-in-class companies perform more simulations earlier. As a leader in virtual prototyping, ANSYS is unmatched in terms of functionality and power necessary to optimize components and systems.
The ANSYS advantage is well-documented.
ANSYS is a virtual prototyping and modular simulation system that is easy to use and extends to meet customer needs; making it a low-risk investment that can expand as value is demonstrated within a company. It is scalable to all levels of the organization, degrees of analysis complexity, and stages of product development.
4.14 INTRODUCTION TO CFD
Computational fluid dynamics, usually abbreviated as CFD, is a branch of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. Computers are used to perform the calculations required to simulate the interaction of liquids and gases with surfaces defined by boundary conditions. With high-speed supercomputers, better solutions can be achieved. Ongoing research yields software that improves the accuracy and speed of complex simulation scenarios such as transonic or turbulent flows. Initial experimental validation of such software is performed using a wind tunnel with the final validation coming in full-scale testing, e.g. flight tests.
4.15 BACKGROUND AND HISTORY
Fig :A computer simulation of high velocity air flow around the Space Shuttle during re-entry.
Fig: A simulation of the Hyper-X scramjet vehicle in operation at Mach-7
The fundamental basis of almost all CFD problems are the Navier–Stokes equations, which define any single-phase (gas or liquid, but not both) fluid flow. These equations can be simplified by removing terms describing viscous actions to yield the Euler equations. Further simplification, by removing terms describing vorticity yields the full potential equations. Finally, for small perturbations in subsonic and supersonic flows (not transonic or hypersonic) these equations can be linearized to yield the linearized potential equations.
Historically, methods were first developed to solve the linearized potential equations. Two-dimensional (2D) methods, using conformal transformations of the flow about a cylinder to the flow about an airfoil were developed in the 190.30s.
One of the earliest type of calculations resembling modern CFD are those by Lewis Fry Richardson, in the sense that these calculations used finite differences and divided the physical space in cells. Although they failed dramatically, these calculations, together with Richardson;s book ;Weather prediction by numerical process;, set the basis for modern CFD and numerical meteorology. In fact, early CFD calculations during the 190.40s using ENIAC used methods close to those in Richardson;s 1922 book.
The computer power available paced development of three-dimensional methods. Probably the first work using computers to model fluid flow, as governed by the Navier-Stokes equations, was performed at Los Alamos National Labs, in the T3 group. This group was led by Francis H. Harlow, who is widely considered as one of the pioneers of CFD. From 1957 to late 1960s, this group developed a variety of numerical methods to simulate transient two-dimensional fluid flows, such as Particle-in-cell method (Harlow, 1957), Fluid-in-cell method (Gentry, Martin and Daly, 1966), Vorticity stream function method (Jake Fromm, 1963),8 and Marker-and-cell method (Harlow and Welch, 1965). Fromm;s vorticity-stream-function method for 2D, transient, incompressible flow was the first treatment of strongly contorting incompressible flows in the world.
The first paper with three-dimensional model was published by John Hess and A.M.O. Smith of Douglas Aircraft in 1967. This method discretized the surface of the geometry with panels, giving rise to this class of programs being called Panel Methods. Their method itself was simplified, in that it did not include lifting flows and hence was mainly applied to ship hulls and aircraft fuselages. The first lifting Panel Code (A20.30) was described in a paper written by Paul Rubbert and Gary Saaris of Boeing Aircraft in 1968. In time, more advanced three-dimensional Panel Codes were developed at Boeing (PANAIR, A0.502), Lockheed (Quadpan), Douglas (HESS), McDonnell Aircraft (MACAERO), NASA (PMARC) and Analytical Methods (WBAERO, USAERO and VSAERO. Some (PANAIR, HESS and MACAERO) were higher order codes, using higher order distributions of surface singularities, while others (Quadpan, PMARC, USAERO and VSAERO) used single singularities on each surface panel. The advantage of the lower order codes was that they ran much faster on the computers of the time. Today, VSAERO has grown to be a multi-order code and is the most widely used program of this class. It has been used in the development of many submarines, surface ships, automobiles, helicopters, aircraft, and more recently wind turbines. Its sister code, USAERO is an unsteady panel method that has also been used for modeling such things as high speed trains and racing yachts. The NASA PMARC code from an early version of VSAERO and a derivative of PMARC, named CMARC, is also commercially available.
In the two-dimensional realm, a number of Panel Codes have been developed for airfoil analysis and design. The codes typically have a boundary layer analysis included, so that viscous effects can be modeled. Professor Richard Eppler of the University of Stuttgart developed the PROFILE code, partly with NASA funding, which became available in the early 1980s. This was soon followed by MIT Professor Mark Drela;s XFOIL code. Both PROFILE and XFOIL incorporate two-dimensional panel codes, with coupled boundary layer codes for airfoil analysis work. PROFILE uses a conformal transformation method for inverse airfoil design, while XFOIL has both a conformal transformation and an inverse panel method for airfoil design.
An intermediate step between Panel Codes and Full Potential codes were codes that used the Transonic Small Disturbance equations. In particular, the three-dimensional WIBCO code, developed by Charlie Boppe of Grumman Aircraft in the early 1980s has seen heavy use.
Developers turned to Full Potential codes, as panel methods could not calculate the non-linear flow present at transonic speeds. The first description of a means of using the Full Potential equations was published by Earll Murman and Julian Cole of Boeing in 1970. Frances Bauer, Paul Garabedian and David Korn of the Courant Institute at New York University (NYU) wrote a series of two-dimensional Full Potential airfoil codes that were widely used, the most important being named Program H. A further growth of Program H was developed by Bob Melnik and his group at Grumman Aerospace as Grumfoil. Antony Jameson, originally at Grumman Aircraft and the Courant Institute of NYU, worked with David Caughey to develop the important three-dimensional Full Potential code FLO22 in 1975. Many Full Potential codes emerged after this, culminating in Boeing;s Tranair (A633) code, which still sees heavy use.
The next step was the Euler equations, which promised to provide more accurate solutions of transonic flows. The methodology used by Jameson in his three-dimensional FLO57 code (1981) was used by others to produce such programs as Lockheed;s TEAM program and IAI/Analytical Methods; MGAERO program. MGAERO is unique in being a structured cartesian mesh code, while most other such codes use structured body-fitted grids (with the exception of NASA;s highly successful CART3D code, Lockheed;s SPLITFLOW code34 and Georgia Tech;s NASCART-GT). Antony Jameson also developed the three-dimensional AIRPLANE code which made use of unstructured tetrahedral grids.
In the two-dimensional realm, Mark Drela and Michael Giles, then graduate students at MIT, developed the ISES Euler program (actually a suite of programs) for airfoil design and analysis. This code first became available in 1986 and has been further developed to design, analyze and optimize single or multi-element airfoils, as the MSES program. MSES sees wide use throughout the world. A derivative of MSES, for the design and analysis of airfoils in a cascade, is MISES,developed by Harold ;Guppy; Youngren while he was a graduate student at MIT.
The Navier–Stokes equations were the ultimate target of developers. Two-dimensional codes, such as NASA Ames; ARC2D code first emerged. A number of three-dimensional codes were developed (ARC3D, OVERFLOW, CFL3D are three successful NASA contributions), leading to numerous commercial packages.
In all of these approaches the same basic procedure is followed.
During HYPERLINK ;http://en.wikipedia.org/wiki/Preprocessor_(CAE); o ;Preprocessor (CAE); preprocessing
The HYPERLINK ;http://en.wikipedia.org/wiki/Geometry; o ;Geometry; geometry (physical bounds) of the problem is defined.
The HYPERLINK ;http://en.wikipedia.org/wiki/Volume; o ;Volume; volume occupied by the fluid is divided into discrete cells (the mesh). The mesh may be uniform or non-uniform.
The physical modeling is defined – for example, the equations of motion + HYPERLINK ;http://en.wikipedia.org/wiki/Enthalpy; o ;Enthalpy; enthalpy + radiation + species conservation
Boundary conditions are defined. This involves specifying the fluid behaviour and properties at the boundaries of the problem. For transient problems, the initial conditions are also defined.
The HYPERLINK ;http://en.wikipedia.org/wiki/Computer_simulation; o ;Computer simulation; simulation is started and the equations are solved iteratively as a steady-state or transient.
Finally a postprocessor is used for the analysis and visualization of the resulting solution.
CASE -1 : RECTANGULAR FIN
MATERIAL – ALUMINUM ALLOY 6061
MATERIAL – ALUMINUM ALLOY
MATERIAL – CAST IRON
FLUID MODELS MATERIALS TEMPERATURE (K) Heat flux(w/mm2)
Max. Min. Oil Rectangular Aluminum alloy 6061 550 447.9 2.9494
Aluminum alloy 550 423.34 2.6816
Cast iron 550 340.67 1.579
Circular Aluminum alloy 6061 550 367.27 2.8642
Aluminum alloy 550 345.64 2.3237
Cast iron 550 303.03 0.9229
Arc type Aluminum alloy 6061 550 441.03 1.9102
Aluminum alloy 550 415.58 1.6765
Cast iron 550 334.89 0.90213
Air Rectangular Aluminum alloy 6061 550 362.15 6.3662
Aluminum alloy 550 341.37 5.3022
Cast iron 550 301.75 2.341
Circular Aluminum alloy 6061 550 310.48 4.1587
Aluminum alloy 550 303.24 3.111
Cast iron 550 295.47 1.09
Arc type Aluminum alloy 6061 550 354.46 3.7025
Aluminum alloy 550 334.74 3.0316
Cast iron 550 299.98 1.257
HEAT FLUX PLOT
In this thesis, a cylinder fin body for a 150cc motorcycle is modeled using parametric software SOLID WORKS. The original model is changed by changing the fin geometries (rectangular, circular and arc type).
In this thesis, two other materials are considered which have more thermal conductivities than Aluminum Alloy. The materials are Aluminum alloy 6061 and aluminum alloy ; cast iron. Thermal analysis is done for all the three materials.
By observing the thermal analysis results, thermal flux is more for Aluminum alloy 6061 than other two materials and also rectangular fin, the heat transfer rate is increased.
So we can conclude that using Aluminum alloy 6061 and taking rectangular fin geometry fluid air.
Thermal Engineering by I. Shvets, M. Kondak
Thermal Engineering by Rudramoorthy
HYPERLINK ;http://books.google.co.in/books?id=TEjZFUcVTbgC;source=gbs_book_similarbooks; Thermal Engineering by R.K. Rajput
HYPERLINK ;http://books.google.co.in/books?id=hBl2IIcbLy0C;source=gbs_book_similarbooks; Thermal Engineering by Sarkar
Gibson, A.H., The Air Cooling of Petrol Engines, Proceedings of the Institute of Automobile Engineers, Vol.XIV (1920), pp.243–275.
Biermann, A.E. and Pinkel, B., Heat Transfer from Finned Metal Cylinders in an Air Stream, NACA Report No.488 (1935).
Thornhill, D. and May, A., An Experimental Investigation into the Cooling of Finned Metal Cylinders, in a
Free Air Stream, SAE Paper 1999-01-3307, (1999). ( 4 ) Thornhill, D., Graham, A., Cunnigham, G., Troxier, P. and Meyer, R.,
Experimental Investigation into the Free Air-Cooling of Air-Cooled Cylinders, SAE Paper 2003-32-0034, (2003). ( 5 ) Pai, B.U., Samaga, B.S. and Mahadevan, K., Some
Experimental Studies of Heat Transfer from Finned Cylinders of Air-Cooled I.C. Engines, 4th National Heat Mass Transfer Conference, (1977), pp.137–144.
(Nabemoto, A. and Chiba, T., Flow over Fin Surfaces of Fin Tubes, Bulletin of the Faculty of Engineering, Hiroshima University, (in Japanese), Vol.33, No.2 (1985), pp.117–125.
Nabemoto, A., Heat Transfer on a Fin of Fin Tube, Bulletin of the Faculty of Engineering, Hiroshima University, (in Japanese), Vol.33, No.2 (1985), pp.127–136.