Research On Evaluation Method Of Vehicle Cooling System Based On Exergy Efficiency

As a special vehicle for modern construction,the construction vehicle has good working performance to ensure the stability of the whole vehicle.With the shortening of the market cycle,the research and development speed of new products is accelerating.In order to better evaluate the heat dissipation performance of the vehicle cooling system,this paper takes a grader in China as the research object and analyzes the heat transfer process of the engine cabin by CFD(computational fluid dynamics).Firstly,according to the mathematical model of the thermal calculation of the radiator,the theoretical analysis of the influence of the cold fluid state on the heat transfer of the four radiators of the grader.It is concluded that the heat transfer of the four kinds of radiators increases with the increase of the flow rate of the cold fluid regardless of the temperature of the cold fluid.When the flow rate increases to a certain extent,the increase of the heat exchange rate is weakened;The greater the temperature difference between the cold fluid and the hot fluid,the better the heat transfer performance.Secondly,the engine cabin model of the grader is established and simplified,and the CFD numerical simulation is used to analyze the three conditions of the low speed forward,reverse and high speed running of the engine cabin under the virtual wind tunnel.Through analysis,the temperature field of the grader,the flow distribution of the air inlet and outlet,and the velocity field are obtained.Thirdly,the engine cabin partition model is established,and the three working conditions of the engine compartment partition model are simulated and analyzed.Then,based on the partition model,the influence of the cooling module to the diaphragm distance on the heat transfer effect of the radiator under low speed forward conditions is analyzed.It is concluded that the heat dissipation power of the four heat sinks is improved when the partition model is compared with the original model under the same working condition under low speed forward conditions;As the distance from the cooling module to the partition increases,the heat dissipation power of the four heat sinks and the temperature drop of the hot fluid are both increased.Finally,the vehicle cooling system evaluation index-exergy efficiency is established.This index is used to evaluate the heat transfer process of the cooling system of each model under the three working conditions of the grader.It is concluded that with the increase of the distance from the cooling module to the partition,the payment and revenue of each power compartment partition model under three conditions are increasing.The distance from the cooling module to the partition is 160 mm,and the efficiency of the power cabin system is the highest in the low-speed forward,reverse and high-speed running conditions.They are 48.55%,30.07%,and 65.63%,respectively.At this time,the heat exchange in the cabin is the most efficient,and the cooling system has the best heat dissipation performance.Figure 40;Table 25;Reference 46...