CFD numerical study on stepless air flow regulation of reciprocating compressor

ZHANG Chun, JIANG Zhi-nong, ZHANG Jin-jie, WANG Yao
(Beijing Key Laboratory of Health Monitoring Control and Fault SelfRecovery for High-end Machinery,
Beijing University of Chemical Technology, Beijing 100029, China)

Abstract: Aiming at the problem of complex and variable internal instantaneous flow field for gas volume adjustment of reciprocating compressor, the dynamic pressure, average temperature and mass of the gas in the cylinder under variable load conditions of the compressor, the movement law of the valve plate and the change of the gas flow velocity in the valve were studied. The relationship between the closing angle of the suction valve and the load value was summarized. A method based on computational fluid dynamics was proposed to simulate the internal flow field of the reciprocating compressor under the condition of stepless gas volume adjustment according to the parameters of the reciprocating compressor and the fluid property parameters. The results indicate that the maximum relative error of compressor cylinder pressure experimental data and simulation data at each stage is less than 10%, which verifies the accuracy of the model. With the hysteresis of the closing angle of the suction valve, the rate of change of the compressor load decreases. When the load decreases, the average velocity of the airflow in the return phase increases, and the maximum value is higher than the maximum value in the inhalation phase. The average temperature of the internal gas rises slightly.
Key words: reciprocating compressor; computational fluid dynamics (CFD); dynamic grid; variable load