Simulation Study Of Diesel Engine Cylinder Liner Coupled Heat Transfer

With the improvement of enriched degree,efficiency combustion and reasonable cooling for engine become key factors to improve the performance of the whole machine.Based on these,lots of researches get breakthrough in the field of simulation.Coupling simulation with multiphase or multicomponent plays a major role in the technology research of engine engineering field.In order to establish an effective simulation method used to guide design and development of internal combustion engine,this paper is based on a four-cylinder turbocharged diesel engine.Combining with theoretical analysis,numerical simulation and experimental research methods,the performance of the diesel engine was respectively discussed under the maximum torque condition and the rated speed condition.In the fluid-solid coupling heat transfer researches for the diesel engine,the mutual influence can be comprehensive considered with engine block,cylinder wall,combustion chamber side and cooling jacket side.Several simulation methods,like 1D and 3D calculation is used for the engine working process simulation,and the cooling jacket heat transfer is calculated by 3D simulation.The temperature and strain analysis for the whole coupling system is calculated by Abaqus on the condition of the boundary results.The main work includes as following:(1)An one-dimensional engine working process model is established,then a series of combustion analysis,like the cylinder pressure,temperature field and heat transfer obtained;Necessary parameters including intake and exhaust temperatures,pressures and mass flow rates is provided for the three-dimensional CFD in-cylinder combustion calculations.(2)3D combustion model is established,the maximum torque and rated speed conditions is calculated and the CFD-FEA coupling module is used,the more accurate boundary conditions for the gas side is gotten for the coupling boundary.(3)Three-dimensional CFD model is set up for cooling jacket.Finally lateral changes about the temperature field and flow field can be obtained at the cooling jacket side.The boundary condition mapping is achieved by using the CFD-FEA coupling,the boundary conditions at the working condition of maximum torque and the rated speed conditions are obtained.(4)Based on the gas side and the cooling water side heat transfer conditions,coupling analysis is accomplished by the combined system with engine block and cylinder liner by using the Abaqus software.At last,a series of analysis results is found for the cylinder liner in temperature field,stress and strain.The in-cylinder combustion,cylinder block,cylinder liner and cooling jacket overall coupling system is analyzed by using the sequential coupling method.The rated speed condition 2500r/min and the maximum torque condition 1500r/min are set up as comparison plan and calculated the finite element simulation,the results show that the temperature of the maximum torque condition is slightly higher than the rated speed condition,the peak stress appear at the top of the cylinder block and the interface of cylinder liner and cooling jacket,which result in a larger deformation in this area.Under this stress influence the coupling system general a fan deformation.