The Vehicle Turbocharger Compressor Flow Analysis And Optimize The Structure For Broadening Map Width

The diesel engine is one of the most widely use power machines,and bulk of the diesel engine are equipped with the turbocharger.With the advantage of fuel,emissions and performance,the growing numbers of scholars pay close attention to the turbo technology.And now the research is focused on improve the pressure ratio,efficiency and the range of the flow width.The compressor include three parts the impeller,the diffuser and the volute.When turbocharger was working,the performance of the compressor eventually affected the performance of the turbocharger,and the compressor's structure and its parameter size determined the performance of the compressor.Therefore the study on the components and structure of the compressor is an important way to expansion the flow width.This paper is based on a vehicle turbocharger compressor,and put the expansion of diesel engine exhaust gas turbocharger compressor stability as the goal.Based on the three-dimensional aerodynamic analysis by using of numerical simulation,this subject has study and optimization the expansion structure.Firstly,by adjusting the angle of reflow slot in the inlet,the compressor's performance was studied.And then,by means of the three-dimensional aerodynamic analysis,purposed two structures to improve the performance of compressor,one is shorten the casing's cavity,the other is design a ring groove on the diffuser's flange part,and jet steam to the diffuser.In the process of numerical simulation,the reverse engineering design method was used to establish the turbocharger compressor geometry model that used in this subject firstly.And then the ICEM was used for mesh the compressor in computation domain,and the combination and rotating meshing method that suited for turbocharger compressor's geometry was purposed.Firstly,studied the compressor's performance by adjusting the reflow slot angle in inlet,and the result of studies showed that,with in limit,broadened the reflow slot angle can delay the arrival of compressor's surge limit and broaden the map width.Based on the flow characteristics of the casing,shorten the casing cavity was proposed to broaden the map width,and because the narrow cavity cut the friction and mixing lost in casing,this structure can improve the compressor's performance.While another expansion structure was proposed that is the jet vapor diffuser.And the casing outlet's axial velocity,casing processing flow,relative speed diffusion ratio and the spiral case's total pressure recovery coefficient has been studied to evaluate its performance.The result showed that this structure can effectively improve the overall performance of the compressor.Compared with the original structure,at the speed of 60000rpm,80000rpm and 100000rpm,steam injection amount is 2g/s,the map width were improved 19.09%,30.83%and 38.71%,the surge limit traffic decreased by 26.58%,29.57%and 17.00%,but the flow range expansion accompanied by some loss of pressure ratio.