Experimental research on stability enhancement for centrifugal compressors using active control casing treatment system

Abstract

Centrifugal compressors are widely used in many fields, where they become unstable when operated at the edge of the surge line. This paper presents a method, which is based on the active control casing treatment to enhance the operating stability of the centrifugal compressor. To investigate the effect of the active control casing treatment system on the performance of a centrifugal compressor, a test rig with rotating speed of 15,000 r/min was built up. The experimental results show that the active control casing treatment system can significantly decrease the surge flow rate and extend the envelope of stable operation via injecting gas (so-called the control gas) into the casing of the centrifugal compressor. The tested maximal enhancement ability is 30.55% at the condition of 10,586 r/min when the flow rate of the control gas is 2.5 m3/min. It was found that the enhancement ability increases with the decrease of the rotating speed of the centrifugal compressor. The increment of the control gas flow rate results in a smaller surge flow rate of the centrifugal compressors.

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“…A few methods of extending the compressor stable operating range have been investigated in centrifugal compressors, such as variable inlet guide vanes, [5][6][7] bleeding slots, 8,9 and other devices. 10,11 Those methods can increase the stable operation range of a compressor and improve the compressor peak pressure ratio and/or efficiency at off-design operating points.…”