Design of a Sector Cascade Applied in the Middle Stage of a Compressor Test Rig

Abstract

A compressor test platform was designed in the purpose of easy assembly and cost-saving tests. New design concepts were firstly used on the test platform and iterative revisions were conducted to verify the effects, which decrease the risk of applying to the full annulus directly. The platform was a sector cascade that can be inserted into an otherwise full stator annulus, with a set of exchangeable endwall casing and blades manufactured by 3-D printing. The platform can create an operating condition which is closer to engine-realistic flow conditions than traditional cascade tests. The flow field of the prototype stator was tested in detail at the operating point and showed some flow defects in the tip region, and then three design plans were conducted to experimentally investigate which design concept could improve the blade tip flow. The concept of casing endwall profiling was the most effective one which markedly depressed the separation of the tip region and decreased the total pressure loss coefficient. The test results show that the design of the test platform was successful and promising, which could be used to conduct more researches on the flow mechanism of the middle stage.