Research On Heat-Flow-Solid Simulation Of Cylinder Head Considering The Influence Of Related Components

With the development of high power density diesel engine, the research on the structural design of the cylinder head has increasingly become a hot and difficult problem. Research on the cylinder head is now focused on the steady-status study of the thermal and mechanical stress of cylinder head. However, people usually ignore the impact of exhaust pipes and other structures when simulating the stress field of cylinder head. In this paper, a heat-flow-solid coupling simulation model was established to analyze the stress field of cylinder head considering the influence of related components, which provides some engineering guidance for the design of cylinder head.The main contents of this paper are as follows:(1) The engine performance simulation software was used to build a model of multi-cylinder diesel engine, the burning pressure in cylinder and vibrated pressure of exhaust pipes can be obtained from the simulation results; a multi-body dynamics model of the engine valve train was established to simulate the impact load of valve seat to the cylinder head; a transient dynamics model, which contains cylinder head combined structure model and other related components, was established to simulate the pressure of cylinder head sidewall which result from the vibration of exhaust pipe.(2) A cylinder head cooling water chamber finite element model, which considering the influence of boiling heat transfer, was established by using ANSYS analysis software. The results of simulation are used to obtain thermal boundary conditions of cylinder head. The experimental test of temperature field in cylinder head was carried out to verify the accuracy of the simulation model. In addition, it is considerable to obtain the regular change of cylinder head cooling water heat exchanger chamber temperature by changing the parameters of boiling heat flow field boundary factor.(3) Based on the cylinder head thermal boundary conditions and force boundary conditions, a transient analysis model which contains combination of cylinder head structure and other related components was established. the simulation results shows that the stress distribution of cylinder head in some local site has significantly increased compared to the results of conventional computation. it is remarkable to study the different stress distribution of cylinder head when the parameters of the cylinder head is changing in different value, which is beneficial for the structural strength design of cylinder head.