Effects of impeller blades with bow trailing edge on centrifugal compressor performance

Abstract

The performance of centrifugal compressors can be improved by reducing the reverse flow intensity of their impellers’ outlet. This study used numerical simulations to investigate the effects of applying bow trailing edge to the impeller blades on the performance of a centrifugal compressor with a wedge diffuser. A peak efficiency 0.87% higher than that of the baseline centrifugal compressor is gained by using positive bow trailing edge on impeller blades. Flow in both the impeller and the diffuser is improved. The results of numerical simulations show that blades with positive bow trailing edges strengthen secondary flow near the blade suction surface in the radial part of the impeller, weaken reverse flow due to the “jet-wake” flow structure, reduce blockage, and render the flow field of the impeller outlet more uniform in spanwise direction. Furthermore, the impeller with positive bow trailing edge blades reduces the separation in the diffuser by improving the distribution of the flow angle at the impeller outlet. This study provides a valuable reference for applying impeller blades with bow trailing edge to advanced centrifugal compressors design in future research.

Effect of Leading/Trailing Edge Swept Impeller on Flow Characteristics of Low Specific Speed Centrifugal Compressor

“…In addition, for the impeller trailing edge at the radial outlet, Hildebrandt et al [22] indicated that the trailing edge backward sweep makes the outlet velocity and flow angle distribution more uniform, which was beneficial in the diffuser inside flow. Li et al [23] analyzed the influence of impeller trailing edge sweep and found that backward sweep can improve flow conditions near the trailing edge, but it can cause non-uniform pressure distribution at the outlet and increase downstream losses in the diffuser. Tian et al [24] studied two types of swept impeller at the trailing edge, incline swept and free swept.…”