Study On Solid-fluid Conjugate Heat Transfer For Cf465Gasoline Engine

The enhancement degree of modern engines keeps increasing, which results in thedeterioration of the work environment of various parts. The top of the piston is burnt and hotcracking of cylinder heads is very common. Emission standards for engines are becomingincreasingly stringent because of the requirements to human life environmental. Andturbocharged engines have higher mechanical intensity and thermal load. Besides,combustion technology requires renovation, which brings serious test to the engine coolingsystem.At the highly fortified Conditions, in order to adapt the engine’s development trendwhich goes towards high-performance, low fuel consumption and high durability and findfundamentally rational solution to the engine cooling problem, proceeding from the coolingsystem is the most direct and convenient way, and solving the internal combustion engines’cooling is very important. Today, the cooling water jacket, which plays a main role in theheat dissipation of the internal combustion engines, has become the main research topic.Therefore, in order to keep the engine in a good working environment all the time and ensurethat the temperature of various parts is in the designed temperature range, the temperaturefield analysis of the solid and liquid of the engine is definitely necessary.This paper is about the study on the solid-liquid-conjugated heat transfer of the cylinderhead and water jackets based on the four-cylinder gasoline engine CF465Q4.The main research work is as follows:1．In this paper, a1D model of this type of gasoline engine is firstly built, usingGT-POWER. The second chapter introduce the details that how the one-dimensionalGT-POWER machine model is built. The engine modeling process includes the modeling of the intake system, the exhaust system, the cylinders, the crankcase, the fuel injection system,and its attachments such as the air filter, and the three-way catalytic converter module. Aftercontinuous debugging, the engine model runs well on full load operating mode when thethrottle is completely open. Compared with the bench test data, the error is controlled at lessthan5%, which proves that the experimental model simulates the state of the original enginebasically. So that, the results sets a foundation for the calculation.2．The third chapter of the paper is the heat transfer simulation of thesolid-liquid-conjugated of the gasoline engine. After adding the gas heat transfer conditions,the output of the one-dimensional model built in the second chapter, to FLUENT to calculate,we can get the speed of the water jacket, pressure, heat transfer coefficient and temperaturecontours. The factor of human interference is reduced during the calculation accordingly.And the results can directly show the heat of the parts.3. The fourth chapter is about the experimental verification and improved design of thecalculation model. The conclusion from the analysis of the model is used in the optimizationdesign of the structure. In this paper, the adjustments and improvements is mainly about thenumber, position and size of the dead zone and upper water stomas in low speed flow regionand the whirlpools which greatly impact the coolant flow. After the simulation of theimproved result, various results of each program are compared.Through the simulation analysis in this paper, the conclusion is as follows:1．For the cylinder block water jacket on the exhaust side of the first cylinder and thecomplex flow region, the flow swirl region and the dead region near the top dead center ofthe cylinder body, the pump structure position is improved as an improvement.2．Improvement measures are taken against the overheating area of the cylinder head.Due to the complexity structure of the cylinder head which is complicated to improve, thenumber and diameter of the upper water stomas is adjusted to improve the temperaturedistribution of the whole cylinder head.3．After the combining the two programs above for the comprehensive optimization ofthe engine, the problem about the flow swirl region and the dead region near the top dead center of the cylinder body is alleviated. And the flow of the water jacket in the upper regionis increased, making the overall flow and temperature field distribution more uniform. Withcomprehensive comparison, the third program is better. But because of the actualimplementation, the second program is more easily realized in the engineering, and theoverall performance of the cooling effect is also good.