A Comparison of Manufacturing Methods, Accuracy, Quality Control and Testing Methods as they relate to High Head Low Flow Impeller Efficiency and Overall Compressor Performance

摘要

This paper presents a detailed analysis and evaluation ofimpeller efficiency and overall compressor performance as theyrelate to specific impeller manufacturing methods,manufacturing tolerances, and quality control. Themanufacturing process used in the construction of an impellerhas a direct influence on the impeller’s performance Theauthors explain and compare different manufacturing methodsand introduce the Taguchi Method Application as an availabletool for statistical evaluation of key manufacturing parametersinfluence on impeller performance.As a best practice, manufacturing techniques for one pieceimpeller production are presented. In the case of high pressurecentrifugal compressor applications with very narrow tip widthimpellers, and corrosive gas applications requiring specialmaterials, EDM (Electrical Discharge Machining) and ECM(Electrolytic Machining) can be applied as a manufacturingprocess to improve quality control over conventionalmanufacturing methods.In response to a compressor performance discrepancyencountered during OEM FAT, a review was initiated intoimproving quality control and performance prediction based onenhanced impeller manufacturing processes for narrow tipwidth impellers.In this analysis, two compressor rotors are evaluated andcompared; the first using traditional, two piece weldedimpellers and the second with one piece impellers machined viaEDM and ECM. The resulting data from both series of testssuggests a significant improvement in individual impellerperformance, as well as overall compressor performance for thesingle piece impeller compared to the two piece impeller.