Clearance effects on performance of twin screw refrigeration compressor

The effects of meshing clearance and discharge end clearance on the performance of twin screw refrigeration compressor are investigated theoretically and experimentally. The theoretical analysis shows that the influence of the meshing clearance on the volumetric efficiency and the adiabatic efficiency of compressor is several-fold greater than the discharge end clearance under the same gap value which is verified by the experimental measure data. The volumetric efficiency of compressor decreases by 0.4% for every 0.01 mm of increasing meshing clearance and drops 0.13% for 0.01 mm of increasing discharge end clearance. The experiments indicate that the change of the discharge end clearance value slightly affects the compressor performance, such as the volumetric efficiency, adiabatic efficiency and COP, when the meshing clearance increases greatly. Moreover, if the gap is enlarged, the volumetric efficiency, adiabatic efficiency, refrigeration capacity and COP all drop. Thus the meshing clearance ought to be paid more attention than the discharged end clearance in the design of twin screw refrigeration compressor.