Effects of Asymmetric Radial Clearance on Performance of a Centrifugal Compressor

The centrifugal compressors are widely used in industrial applications. The design, manufacturing, and installation are all critical for the compressor performance. Many studies have been carried out in the past to optimize the compressor performance during compressor design. The manufacturing tolerances and installation errors can cause the performance drop. There are many compressor performance distortions that are not fully understood due to manufacturing and facilities. In this paper, an asymmetrical radial clearance of the impeller due to manufacturing and installation is studied in detail for the performance impacts. The numerical studies and experiments indicated that the asymmetric radial clearance impacts the compressor flow field structure and performance. Experimental results suggested that the manufacturing and installation cause asymmetric radial clearance which decreased the compressor performance in whole operating range. The numerical analysis demonstrated that the impeller asymmetric clearance impacts performance near the design pressure ratio more than other pressure ratios. The numerical studies showed that the maximum clearance location of asymmetric clearance might impact the compressor performance. The proper asymmetricity of diffuser verse the volute may benefit the compressor performance. The excellent compressor performances for centrifugal compressors especially for small centrifugal compressors not only need to have a good aerodynamic design but also need to control manufacturing and installation carefully.