Modelling of screw compressor capacity control

摘要

The main methods of screw compressor capacity control are shaft speed variation, suction throttling and variation of the suction volume. These have been analysed and are compared by the use of a standard mathematical model which has been adapted for this purpose. The analysis is based on a screw compressor with 5/6, 5/7 and 6/7 "N" rotor profiles for air and refrigeration compressors. The results are compared with experimental data for variable speed of rotation and throttling operation obtained from an air compressor. Two stage expansion with an economizer cycle is also considered.