Simulating the Multistage Environment for Single-Stage Compressor Experiments

Abstract

The performance of a single-stage low-speed compressor has been measured both before and after the introduction of certain features of the multistage flow environment. The aim is to make the single-stage rig more appropriate for developing design rules for multistage compressors. End-wall blockage was generated by teeth on the hub and casing upstream of the rotor. A grid fitted upstream produced free-stream turbulence at rotor inlet typical of multistage machines and raised stage efficiency by 1.8 percent at the design point. The potential field that would be generated by blade rows downstream of an embedded stage was replicated by introducing a pressure loss screen at stage exit. This reduced the stator hub corner separation and increased the rotor pressure rise at flow rates below design, changing the shape of the pressure-rise characteristic markedly. These results highlight the importance of features of the flow environment that are often omitted from single-stage experiments and offer improved understanding of stage aerodynamics.