Influences of the Flow Cut and Axial Lift of the Impeller on the Aerodynamic Performance of a Transonic Centrifugal Compressor

Sung You,Seung Lee,Kun Park,Ali Zamiri,In Jung,Jin Chung

doi:10.3390/en12234503

Abstract

In this study, the influences of the flow cut and axial lift of the impeller on the aerodynamic performance of a transonic centrifugal compressor were analyzed. The flow cut is a method to reduce the flow rate by decreasing the impeller passage height. The axial lift is a method of increasing the impeller passage height in the axial direction, which increases the impeller exit width (B2) and increases the total pressure. A NASA CC3 transonic centrifugal compressor with a backswept angle was used as a base compressor. After applying the flow cut, the total pressure at the target flow rate was lower than the total pressure at the design point due to the increase in the relative velocity at the impeller exit. After applying the axial lift, the total pressure at the design flow rate was increased, which was caused by the reduction in the relative velocity as the passage area at the impeller exit was increased. By applying the flow cut and axial lift methods, it was shown that the variation in relative velocity at the impeller exit has a significant effect on the variation in total pressure. In addition, it was found that the relative velocity at the impeller exit of the target flow rate is maintained similar to the base impeller when the flow cut and the axial lift are combined. Therefore, by combining the flow cut and the axial lift, three transonic centrifugal impellers with flow fractions of 0.7, 0.8, and 0.9 compared to the design flow rate were newly designed.

Highlights

Centrifugal compressors are used in various fields such as power generation, chemistry, and environmental plants, and compressors with varying performance are required [1,2]
The NASA CC3 transonic centrifugal compressor with a backswept angle of −50◦ was used as the base compressor to carry out the study
The high-pressure transonic centrifugal impeller used in this study will be useful for industrial applications when they operate properly within the operating range without shock waves

Summary

Introduction

Centrifugal compressors are used in various fields such as power generation, chemistry, and environmental plants, and compressors with varying performance (pressure and flow rate) are required [1,2]. It is desirable to design a new compressor by modifying the impeller for a compressor that has already been designed and proven in performance. It is necessary to design compressors as a group within a specific flow range by combining impeller modification methods. The first is that compressors with the performance required for each field be manufactured quickly and at a low cost, and the design success rate can be increased. This is because only the impeller is modified in the design of compressors with different performances, so the casings, shafts, and bearings of proven

Methods

Results

Discussion

Conclusion