Experimental Study of the Influence of a Preswirl Fence on the 90° Elbow Flow Uniformity and the Centrifugal Compressor Performance

In this paper, PIV visualization experiments are performed in which a preswirl fence is mounted upstream of the inlet of a compressor to determine the influence of the preswirl fence on the 90° elbow flow uniformity and the centrifugal compressor performance. The results show that if the preswirl fence is installed in front of the 90° elbow it can effectively improve the uniformity of the flow downstream of the elbow. When the centrifugal compressor is operated at low Mach number based on the rotor tip speed, its efficiency remains unchanged or decreases slightly when either a left or right preswirl fence is installed. When the centrifugal compressor runs at high Mach number, its efficiency increases when the right preswirl fence is installed, and its efficiency slightly increases with a substantial increase in head and pressure ratio when a left preswirl fence is installed.