Characteristics of Tip-Clearance Flows of a Compressor Cascade and a Propulsion Pump

Abstract

Tip-leakage flows for a linear compressor cascade and a one-stage shrouded pump rotor are discussed in this paper. A numerical method solving the Reynolds averaged Navier Stokes equations is used to explore various detail features of the tip-leakage flows. Calculation results for the cascade provide an assessment for predicting flow past a non-rotating blade passage with zero and 2% chord clearances. On the other hand, the pump rotor configuration provides a swirling passage flow with the complication of a trailing-edge separation vortex mixed with the tip-clearance and passage vortices and produces a very complex three-dimensional flow in the rotor wake. The physical aspects of the tip-clearance flows are discussed including suction-side reloading and pressure-side unloading due to a tip clearance and formation and transportation of the tip-leakage vortex. Detailed velocity comparisons in the blade passage and the tip gap region are shown to indicate the difficulty of predicting tip-leakage flow. The pressure at the core of the tip vortex is also examined to evaluate the strength of the tip-leakage vortex. Some computational guidelines for design usage are provided for these tip-leakage flow calculations.

Physical Explanations of Tip Leakage Flow Field in an Axial Compressor Rotor

“…Especially, it has been highlighted for the last decade. The complex flow mechanism is getting more and more clarified by the numerous experimental and numerical works (Inoue et al, 1986;Hah, 1986;Murthy and Lakshminarayana, 1986;Dawes, 1987;Inoue and Kuroumaru, 1989;Chen, et al, 1991;Storer and Cumpsty, 1991;Moyle et al, 1992;Adamczyk et al, 1993;Stauter, 1993;Kang and Hirsch, 1993;Lakshminarayana et al, 1995;Zierke et al, 1995;Foley and Ivey, 1996;Lee et al, 1997).…”