Investigation On Three-Phase Coupled Calculation And Temperature Field Experiment In An Engine Cylinder Head

The cylinder head is one of the most important part of an internal combustion engine , which contacts the high pressure and high temperature gas directly, so its working condition is very poor. As the increasing of engine duty, the thermal load of cylinder head has become a key factor which affects the performance of engine. In this thesis , it takes the cooling system item of a six-cylinder direct injection diesel engine as the research background. The author researched cooling water jacket with CFD method and simulated the temperature field of cylinder head by thermal boundary conditions which obtained from the calculation. The following works are included in the thesis:Based on the reading of various literatures, This paper introduce the research states of the cylinder head cooling system and heat transfer, and summarize the methods which can realize the Coupled calculation. Though the temperature measurement test on cylinder head, the thermal conditions are analyzed and the results are obtained for comparison with simulation. Then, the three-dimensional model was set up and the CFD calculations of cooling water jacket were processed. Some advices were given after analyzing the flow in key area of cooling water jacket,meanwhile, the thermal boundary conditions between cooling water jacket and cylinder head were calculated by coupled method. After determining of the calculation model of cylinder head and combustion chamber, the author simulated the combustion and mapped the thermal boundary condition to fire board. At last , the simulation of temperature field and heat stress were completed by cylinder head—gas—cooling water coupled calculation.The calculated results were well in agreement with the measured values, it is show that the coupled calculation were accurate sufficiently .Using the coupled calculation, this paper simulated the temperature field of each six-cylinder and analysed the thermal load of each cylinder. In addition, Base on the analysis of some influence factors to the temperature field of cylinder head, the thesis researched the changes which caused by influence factors and provided some improvement suggestions for further optimum design of cooling water jacket and cylinder head.