Experimental Investigation of the Characteristics of Discharge Pressure Pulsation in a Twin-screw Refrigeration Compressor

To explore the characteristics of pressure pulsation in a twin-screw refrigeration compressor, transient pressures during the suction, compression, and discharge phases were measured, and the pressure pulsation characteristics were subsequently analyzed. The study investigated the effects of operating speed and condensing temperature on pressure pulsation and compared pressure pulsation, noise levels, and the coefficient of performance (COP) in twin-screw refrigeration compressors with slide valve control (SVC) and variable-speed control (VSC) at the same volumetric flow rate. The results indicated that pressure pulsation in a twin-screw refrigeration compressor originates from the periodic fluctuation of pressure and mass flow rate. As the rotation speed increased, pressure pulsation gradually increased from 58.6 kPa at 1380 r/min to 141.0 kPa at 4200 r/min. With an increase in condensing temperature from 34 ℃ to 57 ℃, pressure pulsation also increased from 132.0 kPa to 314.0 kPa. In comparison to SVC, VSC demonstrated significant advantages, featuring more than 54.6% reduction in pressure pulsation, more than 2.9 dB(A) reduction in noise, and more than 5.5% improvement in COP.