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International Journal of Rotating Machinery
Volume 2016 (2016), Article ID 2371524, 19 pages
http://dx.doi.org/10.1155/2016/2371524
Research Article

Stall Margin Improvement in a Centrifugal Compressor through Inducer Casing Treatment

1MSR School of Advanced Studies, Bangalore 560058, India
2Department of Automotive and Aeronautical Engineering, Faculty of Engineering and Technology, M. S. Ramaiah University of Applied Sciences, Bangalore 560058, India

Received 29 December 2015; Revised 7 March 2016; Accepted 16 March 2016

Academic Editor: Ryoichi Samuel Amano

Copyright © 2016 V. V. N. K. Satish Koyyalamudi and Quamber H. Nagpurwala. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The increasing trend of high stage pressure ratio with increased aerodynamic loading has led to reduction in stable operating range of centrifugal compressors with stall and surge initiating at relatively higher mass flow rates. The casing treatment technique of stall control is found to be effective in axial compressors, but very limited research work is published on the application of this technique in centrifugal compressors. Present research was aimed to investigate the effect of casing treatment on the performance and stall margin of a high speed, 4 : 1 pressure ratio centrifugal compressor through numerical simulations using ANSYS CFX software. Three casing treatment configurations were developed and incorporated in the shroud over the inducer of the impeller. The predicted performance of baseline compressor (without casing treatment) was in good agreement with published experimental data. The compressor with different inducer casing treatment geometries showed varying levels of stall margin improvement, up to a maximum of 18%. While the peak efficiency of the compressor with casing treatment dropped by 0.8%–1% compared to the baseline compressor, the choke mass flow rate was improved by 9.5%, thus enhancing the total stable operating range. The inlet configuration of the casing treatment was found to play an important role in stall margin improvement.