Investigation of Compressor Rotor Wake Structure at Peak Pressure Rise Coefficient and Effects of Loading

Abstract

This paper reports an experimental study of the three-dimensional characteristics of the mean velocity in the trailing-edge, near-wake and far-wake regions of a highly loaded low-speed compressor rotor. The wake structure and decay characteristics are compared with the wake data in the same compressor with moderate loading. The experimental investigation was carried out using a rotating five-hole probe. The flow field was surveyed at various radial and axial locations downstream of the compressor rotor. Variations in the axial, tangential and radial components of mean velocity at various axial and radial locations were derived from the data and compared with earlier data at lower loading to discern the effects of loading. It was found that the higher loading had the following effects: Higher total velocity defects were observed in the hub-wall region, increased wake growth rate in the tip region, faster decay of static pressure difference in the trailing-edge region, larger initial wake width in the trailing-edge region, increased rate of growth of the semi-wake width in the trailing-edge region, increased decay rate of radial velocity in the trailing-edge region and decreased decay rate of the radial velocity in the far-wake region. Far wake properties were almost identical in both cases.

Experimental Investigation of the Flow Field in a Multistage Axial Flow Compressor

“…The swirl angle distribution across the wake indicates the usual overturning and underturning on the suction and pressure side of the wakes, respectively. This is consistent with the wake data in a single stage compressor rotor (Prato and Lakshminarayana, 1993). The endwall region has overturning in the corner region formed by the suction surface and the wall and this is caused by the secondary flow.…”