AERODYNAMIC AND AEROACOUSTIC OPTIMIZATION OF A TRANSONIC CENTRIFUGAL COMPRESSOR

The performance of transonic compressors can be characterized aerodynamically and aeroacoustically. In this paper, the DLR SRV2 compressor without vaned diffusers and its redesigned version are studied. The redesign strategy (Zangeneh et al. 2011 [1]) utilized the 3D inverse design and CFD analysis. Both compressors were analyzed in ANSYS CFX 11, and the computational results show that the predicted pressure-ratio and efficiency of the original compressor have good agreement with experimental results. The simulations have also revealed that the redesigned one is superior at both design and off-design points at different rotating speeds. This work applies a convective FW-H method to further investigate the noise radiation from these two compressors. As the blade tip speed is supersonic, the permeable integral surface scheme must be adopted. The flow quantities needed as the inputs to the FW-H solver were extracted from the CFD solutions. The numerical predictions of the noise SPLs at blade passing frequency and its harmonics match the experimental measurements reasonably well. It is found that the original compressor has significant variations of SPLs as the operating mass flow rate changes whereas the redesigned one has much slighter variations. At peak efficiency the redesigned compressor has a lower noise level. This study provides insights for the optimal design of a transonic compressor when good aerodynamic and aeroacoustic performance are both required.