Research On The Structure Optimization Of The Air Chamber Of The Intercooler For Heavy Vehicle Based On CFD Technology

In recent years,the problem of automobile exhaust pollution emissions has been paid more attention by countries which has developed a more stringent emission standards.Turbocharging technology can not only improve the engine power,but also can significantly reduce the emissions of NOx,PM and other pollutants,so it is widely used in heavy duty trucks and various types of cars.After the matching of the heavy duty vehicle in the engine cooling system,there are some problems exist universally which includes the cooling capacity of the intercooler is poor and the engine intake air temperature is high.In order to meet the higher emission standards and reduce the content of NOx,the performance of intercooler should be improved.Aiming to solve this problem,this paper takes a intercooler of heavy duty vehicle as an example,making research on heat transfer performance and flow performance about intercooler with the structure by CFD Technology,and the structural parameters are optimized and improved on this basis.Firstly,the three-dimensional model of the intercooler is established according to the structural parameters of the intercooler by Pro/E software and ICEM software is used to clean and mesh model,then the flow field of internal charge air in intercooler is simulated and calculated by FLUENT.The simulation results of the pressure loss and heat transfer was discussed and analyzed,which shows the air chamber is the main component of the intercooler pressure loss,and air flow distribution in air chamber directly affect the cooling performance,therefore the optimization of chamber structure is the main research contents of this paper.Secondly,according to the national standard GB/T 23338-2009 “engine air cooler technical conditions”,bench test of the intercooler is carried out.After this,heat dissipating capacity and pressure loss results are compared between test and simulation.The results show that the test and simulation results are coincided,which confirms the effectiveness of FLUENT simulation results.Then,the structure parameters of the air chamber are discussed and optimized.On the one hand,CFD simulation model of different side wall dip angle are established and simulated to find its effect on the heat transfer and flow performance.the results show that the pressure loss of the intercooler will decrease with the increase of the side wall dip angle in a certain range.However the increase of the side wall dip angle has less enhance on heat transfer performance.Therefore,the research about guide vane in inlet chamber is conducted to improve the heat transfer performance.There are many structural parameters that affect the performance of air flow and heat transfer,so the Isight software is used to establish the Craig agent model and ASA algorithm is chosen to optimize the agent model then the optimum structural parameters of the guide vane are obtained.After optimization of the structure,the outlet temperature of the intercooler is reduced by 9.8? and the pressure loss is reduced by 2.61 kPa,which achieved the optimization goal.Finally,the emission and economic performance of the diesel engine are tested to compare the change of the engine performance after the optimization of intercooler.The test results show that the emission performance and economic performance of the diesel engine are improved,what's more,the NOx emission and exhaust smoke have an obvious improvement.The results of this paper provide a useful reference for the structure design,parameter optimization and performance improvement of the intercooler.