High engine oil temperatures have detrimental effect on overall engine performance and durability. High oil temperature is a direct indication of high engine temperature and hence, the inefficient cooling system of the engine. In this paper we show how the systematic investigation of cooling system thought experiments and CFD modeling can reduce the engine oil temperature within the desirable limit. A CFD model was developed for the entire cooling system and results were validated with the experimental measurements. The CFD model and experimental measurement techniques have been described in detail. Separate experimental measurements were conducted for flow and thermal measurements and the corresponding CFD model was validated against these measurements. Various design concepts were investigated and its effects on engine heat transfer coefficients and temperatures, change in system resistances, flow rates and other parameters have been presented. A simple experimental setup was developed for optimization of the centrifugal fan. The optimized fan was then used in the CFD model. It was observed that the reduction in engine oil temperature could be achieved by systematic design changes. However, it comes at the expense of increase in system resistance.

This thesis looked at the effect of clay and silt soil blocking the heat transfer area of the radiator and its effect on the engine coolant through the conduct of experiments and a mathematical model developed. The results indicated that the percentage area covered resulted in a proportional increase of the inlet and outlet temperatures of the coolant in the radiator. The mathematically model developed also predicted the experimental data very well. Regression analysis pointed out that every 10% increase area of the radiator covered with silt soil resulted in an increase of about 17 oC of the outlet temperature of the radiator coolant.Similarly, using clay as a cover material, 10% of the area covered of the radiator resulted in an increase of about 20 oC of the outlet temperature of the radiator coolant. Statistical analysis pointed to the fact that the result obtained for clay, silt and the mathematical model were not significantly different. Thus, irrespective of the type of material that blocks the radiator surface area, the coolant rises with proportion of the radiator covered.

Recent developments in automotive industry tend reseachers to design engines of lower volumes and higher efficiencies. Volume reduction enhances the generated heat per volume which in turn requires effective cooling methods to avoid thermal stresses on the engine walls. Nowadays nanofluids are extensively welcomed and employed as effective working fluids with efficient cooling potentials. In the present study effects of adding nanoparticles to the pure water as the cooling working fluid in the radiator is assessed. The employed nanoparticle is TiO2. A 3D model of engine with the cooling passages is simulated by CFD both for the pure fluid (water) and nanofluid. It will be shown employing 1%)vol( TiO2 nanofluid improves cooling heat transfer up to 37% in comparison with the pure water.

With the development of engine technology, modern engine power has been improved a lot. Therefore more precise analysis is of much importance. There is more emphasis put on the research on the design of cooling system. An efficient way to study heat transfer in cooling passage of an engine is CFD calculation. With CFD analysis flow pattern in coolant jacket could be analyzed. In this research the velocity, pressure and heat transfer coefficient distribution in the cooling passage of a 4-cylinder SI engine are computed via CFD code AVL Fire. The main goal of author's work is to investigate the precise cooling. Therefore, the effects of head gasket holes on the flow distribution in the hot spot critical regions of the cylinder head can be seen. Three different schemes are proposed to enhance the flow distribution in cylinder head and finally the results are discussed.

In this study, AL2O3+H2O nanofluid was used in a laboratory setting to test the thermal performance of the M13NI engine. AL2O3 nanoparticles were employed in this experiment along with base fluids made of water and ethylene glycol. We employed 20 nm nanoparticles with volume fractions of 1 to 2%. The outcomes demonstrated that the AL2O3 nanofluid made in the first 22 days was stable after being added SDBS sulphate. Additionally, the zeta potential, which was calculated to be 37.7 mv, shows the stability of the nanofluid. The heat transmission and pressure drop rose as the volume fraction of nanoparticles increased, while the merit parameter fell (ratio of heat transfer to pump power). At 1150 RPM and 1% volume fraction of nanoparticles in the water-based fluid, it was found that the heat dissipated increased by 7.2 and 13.1% in comparison to the mixture of water+ethylene glycol and pure water, respectively. When the volume proportion of nanoparticles in the base fluid increases, the radiator's outlet temperature decreases, resulting in a greater difference between the inlet and outlet temperatures and a faster rate of heat transfer. By utilizing nanofluid, it is possible to lower the radiator's size and the volume of the cooling system, so reducing the volume of circulating water and the engine's wasted power.

Radiators are among the essential parts of car engines, and any weakness or defect in them can cause severe damage to the engine. The most critical tasks of radiators is effective heat transfer between air and fluid inside the radiator tubes, which is done by fans. Since the air temperature has a direct relationship with its pressure, measuring the air pressure before and after the radiator is necessary. In this research, three different methods have been used to calculate the air pressure drop at speeds of 3, 5, and 8 m/s. The purpose of this work is to introduce the best possible method to reduce the risks that are caused by the wrong reading of the air pressure drop using the accuracy of the obtained results, The point that each part of the radiator is determined by which pressure (static or dynamic pressure) is crucial and plays an essential role for choosing better type of pressure gauge. If this is done, the obtained results will be correct. If the air pressure drop is not calculated correctly, it can cause severe damage to the engine and other car parts. The best method that has the slightest error and the least risk for car radiators is when the pressure gauge calculates the static pressure inside the wind tunnel and the dynamic pressure outside the wind tunnel. In this case, the error of the obtained results comparing to the standard results is 9. 16, 15. 41 and 10. 18%, at speeds of 3, 5 and 8.

Radiators are among the essential parts of car engines, and any weakness or defect in them can cause severe damage to the engine. The most critical tasks of radiators is effective heat transfer between air and fluid inside the radiator tubes, which is done by fans. Since the air temperature has a direct relationship with its pressure, measuring the air pressure before and after the radiator is necessary. In this research, three different methods have been used to calculate the air pressure drop at speeds of 3, 5, and 8 m/s. The purpose of this work is to introduce the best possible method to reduce the risks that are caused by the wrong reading of the air pressure drop using the accuracy of the obtained results, The point that each part of the radiator is determined by which pressure (static or dynamic pressure) is crucial and plays an essential role for choosing better type of pressure gauge. If this is done, the obtained results will be correct. If the air pressure drop is not calculated correctly, it can cause severe damage to the engine and other car parts. The best method that has the slightest error and the least risk for car radiators is when the pressure gauge calculates the static pressure inside the wind tunnel and the dynamic pressure outside the wind tunnel. In this case, the error of the obtained results comparing to the standard results is 9. 16, 15. 41 and 10. 18%, at speeds of 3, 5 and 8.

The engine fin is an essential component that significantly impacts the cooling system's effectiveness and overall performance. Although the engine fin is used to dissipate heat generated, an attempt to enhance the effective surface area for the fin needs to be addressed. This research aims to enhance the effectiveness of engine cooling systems through the fin design, which may involve incorporating slots to expand the surface area and improve overall efficiency. The analysis involved two fin geometries, rectangular and cylindrical fins, made of Aluminum 1100 material. The design models are created using the computer-aided design software PTC CREO Parametric 6.0., and steady-state thermal analysis and modal analysis were performed using ANSYS 2023 R1. The steady-state thermal analysis results indicate that the slotted cylindrical fin design demonstrated the highest heat transfer rate compared to the conventional fin design. The results from this study are expected to provide valuable performance in improving heat dissipation.

The Stirling Cycle is one of the thermodynamic cycles that is close to Carnot cycle in term of theory, and these advantages cause to using Stirling engines in wide industries. The main objective of this research is experimental investigation of Stirling Gamma engine for refrigeration. In this investigation, effect of working fluid air and helium, operatring pressure of working fluid and dynamo power on refrigereation generation have been investigated. Results show that with using air fluid with power 520. 8 W and operating pressure 3 bar and in 10 minutes could reach to temperature-23°, C and with using Helium fluid in power 420 W and operating pressure 6 bar and in 10 minutes could reach to temperature-21°, C. In experimental implement has been tried to reach lower than 10 percent error results in various part of engine like, insulation, leaking, belt lash and measurement devise Results show that increasing power of power supply mean gas pressure, time of turning on power supply and using fluid such as air, helium are effective in refrigeration.

Upgrading the thermal efficiency of the cooling system of liquid rocket engines is one of the most significant and intricate problems in designing modern rocket engines in the missile industry. The present study employed the Bees algorithm (BA) to attempt a single-objective optimization of the cooling system of the combustion chamber and nozzle of an LH2/LOX rocket engine considering the overall heat transfer coefficient objective function and four parameters, including the diameter and thickness of the cooling tubes, the radius of the throat, and the mass flow rate of liquid hydrogen (cooling fluid). The optimization was examined by the heat transfer analysis of combustion gases with the chamber walls, the use of the BA optimization algorithm, and the consideration of the sensitivity of the design parameters regarded for the overall heat transfer coefficient objective function. In this respect, these parameters were considered constant in the design ranges, while other parameters were variable. The results show that the overall heat transfer coefficient can increase almost by 17.78% during the optimization process of the cooling system of this rocket engine through the parametric analysis of the four mentioned design parameters.