Performance Matching And Optimization Study Of Engine Cooling System Based On 1D/3D Integrating Simulation

Engine cooling system is an important subsystem in vehicle thermal management,its performance directly affects the vehicle's power,economy,comfort and emission performance.With the increasing degree of engine enhancement,the engine's power density is increasing,and the comfort requirements of people on the crew cabin are gradually increased,which will bring a greater burden to the engine cooling system.This phenomenon can cause the engine cabin flow field and the temperature field are unreasonable,resulting in the engine cooling system performance degradation,the coolant temperature is too high or even "boil" risk.Therefore,it is one of the important technical problems to be solved urgently to design the engine cooling system reasonably and ensure the temperature of the coolant in the proper range.Based on the cooperation project between schools and enterprises,this paper uses the one-dimensional/three-dimensional joint simulation method to analyze the automobile cooling system,which lays the foundation for the development of the cooling system.The main contents are as follows:(1)Basing on the advanced heat exchanger module of one-dimensional hot fluid software Flowmaster the car radiator model is constructed.Under the same radiator's windward area,and taking the radiator heat transfer as the objective function,the orthogonal test method was used to study the each factor's effects on heat transfer performance.Also the influence degree of each factor on the heat transfer performance was determined by the range analysis.The optimal combination of high heat transfer performance and the followed standard of actual selection are obtained.(2)According to the actual arrangement of the cooling system and the test data of each component,the one-dimensional simulation model of the cooling system is established,and the pressure,temperature and velocity distribution of the cooling system under the three conditions of urban,climbing and high speed are calculated.On the basis of this,the influence of the heat transfer of the condenser and the oil cooler on the temperature of the engine coolant is analyzed.Sensitivity analysis of the influence factors such as ambient temperature,humidity,pressure and engine power is carried out,which provides the basis for intelligent control of cooling fan and water pump.(3)Based on the simplification of the engine compartment model,the porous media model of each heat exchanger,the volume heat source model and the fan momentum source model were constructed.Three-dimensional CFD was used to analyze the flow field and temperature field of the engine compartment.The results indicate that there is a high temperature area in the engine compartment,which is unfavorable to the heat exchanger heat.Therefore,in order to improve the thermal environment in the cabin,the cooling module flow field and temperature field are analyzed by changing the installation location of the fan and the relative arrangement between the different arrangements respectively.The results show that,when the fan is in the middle position and the condenser,the oil cooler are placed in the top of the radiator,the overall performance of the heat exchanger module is optimal and the thermal environment in the engine compartment is improved.