Efficiency evaluation of a miniature multi-stage compressor under insufficient inter-stage cooling conditions

A miniature multi-stage compressor (MMSC) with an integrated inter-stage cooler has been proposed. This study aims to evaluate the efficiency of each stage of the MMSC under insufficient inter-stage cooling conditions through numerical simulation. The results show that the volumetric efficiency of first-stage, second-stage, third-stage and fourth-stage reduced by an average of 1.43%, 1.86%, 2.32%, and 2.56% respectively as suction temperature increases every 10 degrees C, indicating that the temperature has more remarkable influences on the volumetric efficiency with the increase of pressure and the decrease of cylinder diameter. For every 10 degrees C increase in temperature, the isentropic efficiencies are all reduced by about 1%. And it should be noted that when the suction temperatures of the second, third, fourth stage cylinder exceed 120 degrees C, 70 degrees C, and 50 degrees C, respectively, the valve flutters severely, indicating that the valve has a poor applicability to the current operating conditions. (C) 2018 Elsevier Ltd and IIR. All rights reserved.