Numerical Investigation of Impeller Tip Tailoring and its Impact on Aerodynamic Design of a Centrifugal Compressor’s Impeller

Abstract

The current research focuses on the aerodynamic design of a centrifugal compressor and the effect of tip tailoring on the aerodynamic impeller efficiency. To this extent a high-fidelity multi-point design optimization process has been developed and exploited on a high pressure ratio transonic impeller. By manipulating the shape of the impeller blades and endwalls and by including advanced geometrical features such as winglets on the impeller blades, the behavior of the impeller flow has been investigated. Here, the results of three-dimensional RANS simulations with the Spalart-Allmaras turbulence model on a structured multi-block mesh is used for the evaluation of the flow characteristics. In the context of radial machines, the results of the aerodynamic design optimization show an important improvement of the impeller isentropic efficiency compared to the reference impeller, with a significant contribution from the presence of the impeller tip winglets. Furthermore, the integration of the impeller winglet has encouraged this study to provide a detailed analysis on the impeller flow structures in order to have a better understanding of the effects of tip tailoring on impeller performance.

Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance

“…The recessed tips were also effective in reducing the tip leakage flow. Recently Mahajan et al [16] had carried out computations on a transonic centrifugal compressor with a winglet on the suction side of the impeller blade near its tip. They had shown that the isentropic efficiency of the impeller with winglet was improved compared to the reference impeller.…”