| The development of turbocharger technology intimately connected with the research of small turbocharger, as a key component of turbocharger,the study of centrifugal compressors has been received great interest by researchers in turbomachinery aerodynamics.The demand for high pressure ratio and wide flow rate makes the inlet velocity of centrifugal compressor more and more higher,the internal flow more and more complex,which brings a lot of complex flow phenomena,so that some useful flow control measures are needed to prove the internal flow situation of compressors.As an excellent flow control measure,aerodynamic sweep has a great influence on shock wave,secondary flow,leakage vortex of transonic centrifugal compressors,it has a certain significance to study transonic centrifugal compressor with aerodynamic sweep.This paper investigated a small transonic centrifugal compressor by designing different kinds of swept blade,trying to explore some mechanisms of aerodynamic sweep.Numerical simulation was used to investigate the influence of aspects as follows on aerodynamic performance of centrifugal compressors:1,the influence of main blade leading edge sweep on the aerodynamic performance of centrifugal compressors;2,the influence of main and splitter hybrid leading edge sweep on the performance of centrifugal compressors;3,the influence of splitter on the performance of centrifugal compressor.Through the different sweep degrees could control the loss near endwall and change the structure of blade tip shock wave,different kinds of swept schemes were designed based on unswept blade,the numerical situation study conducted that the optional sweep angle of all design schemes occurs at 10°forward sweep,whose internal flow was better than others’,the internal shock wave and low energy flow had a significant improvement, the overall efficiency increased 0.72% over unswept blade.The splitter blade sweep is carried out on the basis of main blade sweep.Two types of hybrid swept blades were designed,after comprehensive comparison concluded:(1)Main blade and splitter blade forward sweep increased overall efficiency 1.2% over unswept blade, and it had obvious improvement for internal air flow of impeller;contrasted with main blade forward sweep and splitter blade forward sweep,hybrid forward swept blade still had significant superiority.(2)Main blade backward sweep and splitter blade forward sweep was better than other schemes,it had some influence on the mach region of blade root,the overall efficiency increased 0.9% over unswept blade.This paper also studied the influence of the splitter blade circumferential position and axial chord length on the centrifugal compressor performance, the result showed that it had most obvious effect on the performance of centrifugal compressor when the splitter was near to pressure side of main blade;when the length of axial chord was half of main blade,it became available to performance of centrifugal compressor by reducing losses. |
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