Finite analysis of cylinder temperature field in boil-off gas compressor

Boil-off gas (BOG) compressors operate at low suction temperature and suffer from great temperature change when the working condition changes. In this study, the FEM simulation of heat transfer in a BOG compressor was performed, and the static and periodic transient temperature fields and their changes were obtained during the compressor starting both under ambient condition and precooling conditions. The results show that, when the BOG compressor operates steadily, the average temperatures in the suction chamber and the discharge chamber of the cylinder are -97°C and -21°C, respectively, and the amplitude of temperature fluctuation is less than 0.1°C in the periodic transient temperature field. In addition, the maximum temperature difference in the cylinder is 53.5°C when the compressor starts at -30°C while it is 87.1°C when the compressor starts under the ambient condition (at 30°C).