Heat Transfer Analysis Of Fluid-solid Coupling Of Air-filled Gasoline Engine Cylinder Head And Optimization

The cylinder head plays an important role in the actual working process of theengine. The cooling performance of the cylinder head has a direct influence on theworking reliability of the engine. If the cooling performance of the cylinder head isinsufficient, it will lead to decrease the intension of the cylinder head dramatically andif the cooling performance of the cylinder head is not even, it will lead to increase thetemperature gradient of the cylinder head, thus resulting in too much stress and breakingthe cylinder head. So it is important to study the cooling performance of the cylinderhead.The research target of this paper is an air-cooling gasoline engine cylinder head.After a long time operation, it is easy to overheat for the cylinder head and reduce theworking life of the machine greatly. To research the heat process of cylinder head, thispaper makes numerical simulation of CFD and fluid-solid coupling to get the velocityfield of cool air and temperature field of cylinder head. In order to measure thetemperature field distribution of cylinder head, this paper established a test platform. Ituses a heat image maker to measure the temperature of cylinder head, the measurementmethod is relatively simple and convenient, and the measurement results are accurate.And then compare the map with the result of the experimental temperature field toprove that the numerical simulation of fluid-solid coupling is feasible. At the same time,provide the reference for the heat load estimate of cylinder head.In order to strength the cooling performance of cylinder head, this paper optimizedthe structure of cooling fin. By increasing the cooling surface of fin, it improves itscooling capacity. The outside stiffened plate of cylinder head at fin roots block coolingair swept fin’s root and wall behind stiffened plate. So in the condition of not affectingthe structural strength of cylinder head, optimize outside stiffened plate to improve thecooling performance of fin’s root and wall behind outside stiffened plate.In the actual process, the cooling air can’t sweep the cylinder wall of hightemperature, where the spark plug is installed, and leads to the insufficiency of thecooling performance. So it is necessary to drill the cooling air channel to cool thecylinder wall of spark plug installation hole. This paper summarizes the basic principlesof air channel design and introduces six different types of air channel. Compare andanalysis their cooling performance, then select the best performance model in the engineering practice.Finally, the cylinder head with half-open air channel is produced according tooptimization scheme, then installed and tested it. The results of testing measurementinformed the heat load of optimized cylinder head have greatly reduce comparedoriginal cylinder head, and proves the optimization scheme is feasible.