Coupled Thermal And Mechanical Load Analysis In Diesel Cylinder Liner-Piston Group

The diesel engine has been widely used because of its high thermal efficiency, torque, durability features, but at the same time, as people continue to put forward new requirements on diesel power, economy, emissions and other important performance indicators, higher requirements are put forward to structural optimization and improvements. Obviously, to improve the working environment of the combustion chamber components to make it stable and safe operation and to improve the overall reliability of the diesel engine is the most important. Piston and cylinder liner as important parts of the combustion chamber, the working environment is very bad, not only bear the periodic heat load of the high temperature gas, but also withstand the gas pressure, the reciprocating inertia force and other mechanical load, and are the reason for piston cylinder scoring, cracking, deformation. Therefore, it is necessary to finite element analysis under thermal load and mechanical load on the cylinder liner-piston group, calculate and analyze its stress and strain distribution, to provide a theoretical basis for structural optimization and improvements of the piston and cylinder liner.Selecting4100ZBQ diesel engine which designed and made in Kunming Yunnei Power Company Limited as the research object, using UG to establish three-dimensional solid parametric model of the piston, cylinder liner and piston rings, after selecting the appropriate unit model and meshing method, the solid model was meshed in the ANSYS Workbench platform. In combination with diesel engine measured data, the empirical formula and related examples, outer boundary conditions between parts were transformed into inner boundary conditions of the component, heat transfer boundary conditions of every region of the cylinder liner-piston group model was determined, and then, the steady state thermal analysis of cylinder liner-piston group was performed under rated condition. With indirect coupling method, taking the steady-state temperature field of the cylinder liner-piston group as the temperature boundary conditions of the structural analysis, stress and strain distribution of the assembly were analyzed and calculated in the case of thermal load, mechanical load and thermo-mechanical coupling load. By comparing and analyzing stress and strain distribution of cylinder liner-piston group in the three load conditions, dominant factors of stress concentration and excessive deformation of different regions were put forward and analyzed their reasons. Finally, some preliminary exploratory improvements for structure were presented.Through the finite element analysis of the above, we have got the results of temperature field, stress field and strain distribution of the cylinder liner-piston group under rated condition, have offered certain theoretical basis for the future analysis and design and structure optimization.