The Turbocharger Compressor Casing Structure Modification And Three-dimensional Aerodynamic Analysis

The diesel engine is still the main machinery of the social production department,but due to the limited energy and the corresponding laws,as well as the increasingly serious environmental problems,inevitably put forward higher requirements to the diesel engine efficiency,performance and environmental protection.Exhaust turbo charging technique provided an effective solution for this request.Turbocharger used the waste gas that internal combustion engine produced to drive the compressor to compress the air,providing enough air for fuel combustion.Not only used of exhaust gas,but also improved the combustion efficiency of fuel.Due to customer needed diesel engine can work steadily at the complicated condition,which required the performance of the turbocharger needed to be further improved.While turbocharger was working,the performance of compressor ultimately affected the performance of the turbocharger,and the compressor casing processing technology was an effective expansion technology.In this paper,put the expansion of diesel engine exhaust gas turbocharger compressor stability as the goal,modified the casing structure of an existing turbocharger compressor and did three-dimensional aerodynamic analysis by means of computational fluid dynamics.In three-dimensional aerodynamic analysis for compressor,set up the calculation model of three-dimensional aerodynamic analysis firstly,the reverse engineering design method was used to establish the turbocharger compressor geometry model that used in this subject.Then meshed the three-dimensional flow field of compressor?When was meshing,a meshing method that suited for turbocharger compressor's flow field was purposed.In the numerical simulation of turbocharger compressor's performance,understand the effect of casing through the simulation of compressor with the original casing structure,understand the effect of casing through the simulation of compressor with the original casing structure,then modified the original casing structure,put forward the axial lead casing structure,two main structural parameters which were reflow slot width and axial lead hole number were studied and the result of studies showed that broadened the reflow slot width can delay the arrival of compressor's surge limit and broaden the map width,the efficiency of compressor was slightly reduced at compressor's test points when the slot width was increased,because of the more friction and mixing lost in casing.With the increase of the number of holes,the stable working range of the compressor increased first then down warded under middle and high speed,and the efficiency was on the decline.The trend of the stable working range mainly because the import of local flow field had been affected with an increase of axial lead hole number,which leaded to the adjacent hole restrain each other in export.And the efficiency was decline due to the more gas in friction and mixed.Comparing the casing structure of this topic and the original structure of casing structure.When at the five representative speed,the new structure could result in the following survey results:surge limit flow rate reduced by 0.084%,16.8%,14.68%,13.63%and15.7%.the flow width broadened by-4.63%,17.4%,9.7%,10.1%and 12.8%.the maximum pressure ratio increased by 0.64%,2.63%,3.23%,2.51%and 1.95%,respectively.