Development and Performance of the Wedge-Type Low Specific Speed Compressor Wheel

Abstract

Low flow, low specific speed compressor stages are known to have inherently low performance level. Their low performance is attributed to a number of factors such as: high internal friction, disk friction, and leakage losses per unit mass flow. Comparative studies of design and performance indicated that it was possible to improve performance of the low specific speed compressor stages through the use of more favorable flow passage cross sections in the impellers. Use of wedge-shaped blades makes it possible to form such impeller flow passages. A major development program, started in early 1960’s, led to the emergency of the wedge-type compressor wheel as the wheel for low flow, low specific speed applications. The wheel is capable of operating in flow ranges previously designated for reciprocating compressors with an excellent operating range and good efficiency.

Design and Performance Evaluation of a Very Low Flow Coefficient Centrifugal Compressor

“…The following descriptions review some research work regarding design of low flow coefficient centrifugal compressors. Rusak [3] briefly presented three types of impeller design for low flow application: low flow conventional stages with 2D impellers, low flow high pressure coefficient stages with radial impellers, and very low flow stages with wedge-type impellers. Casey et al [4] designed and tested several low flow coefficient centrifugal compressors with high head and low outlet meridional velocity component.…”