## 05 - Propulsion## AXIAL ASSEMBLAGE DEVIATION ON PERFORMANCE OF ONE TRANSONIC CENTRIFUGAL COMPRESSOR
The paper researched the influence of the axial assemblage deviation on the performance of one transonic centrifugal compressor taken the method of numerical simulation and experimental verification. The analysis results show that, resulting of the assemblage deviation the modification of impeller blade tip clearance at outlet has a very significant influence on the performance of whole centrifugal compressor stage and the impeller, also the matching relationship between the impeller and radial diffuser.rnrnThe pressure ratio and efficiency if the centrifugal compressor stage and impeller increase obviously with the decrease of axial assemblage deviation, comparing with the characteristic curves of Mass flow-pressure ratio and characteristic curves of Mass flow-efficiency with different axial assemblage deviations. As the relative blade tip clearance decline from 2.21% to 0.74% in design flow rate, the pressure ratio of centrifugal compressor increase 1.82% and the efficiency increase 0.26%, the pressure ratio of impeller increase 2.01% and the efficiency increase 0.35%, however, the radial diffuser pressure ratio decrease 0.23%.rnrnResults on the compressor flow field indicate that, the axial assemblage deviation decrease, therewith, the blade tip clearance decrease which reduce the leakage flow and the range of low velocity zone, and weaken the entrainment of high energy flux near the pressure surface to the suction surface which promote the pressure boosting capability and efficiency of impeller. But the Mach number become larger as the smaller clearance leading to a smaller area on the outlet of impeller, which increase the high Mach number area on the inlet of radial diffuser, that increase the shock wave losses and enlarge the boundary layer separation. Therefore, the efficiency of radial diffuser decrease with the increase of impeller tip clearance, which make the stage do not get the significant efficiency increment as the matching relationsh |