SIMULATING THE MULTISTAGE ENVIRONMENT FOR SINGLE-STAGE COMPRESSOR EXPERIMENTS

The performance of a single-stage low-speed compressor has been measur ed both before and after the introduction of certain features of the m ultistage flow environment. The aim is to make the single-stage rig mo re appropriate for developing design rules for multistage compressors. End-wall blockage was generated by teeth on the hub and casing upstre am of the rotor. A grid fitted upstream produced free-stream turbulenc e at rotor inlet typical of multistage machines and raised stage effic iency by 1.8 percent at the design point. The potential field that wou ld be generated by blade rows downstream of an embedded stage was repl icated by introducing a pressure loss screen at stage exit. This reduc ed the stator hub corner separation and increased the rotor pressure r ise at flow rates below design, changing the shape of the pressure-ris e characteristic markedly. These results highlight the importance of f eatures of the flow environment that are often omitted from single-sta ge experiments and offer improved understanding of stage aerodynamics.