Effects of lubricating oil on the performance of a semi-hermetic twin screw refrigeration compressor
Wu, X and Xing, Z and He, Z and Wang, X and Chen, W, Effects of lubricating oil on the performance of a semi-hermetic twin screw refrigeration compressor, Applied Thermal Engineering, 112 pp. 340-351. ISSN 1359-4311 (2017) [Refereed Article]
Crown Copyright 2016 Published by Elsevier Ltd. All rights reserved.
Lubricating oil is often employed in a twin-screw refrigeration compressor for lubricating bearings, sealing
leakage paths, cooling refrigerant gas and regulating capacity. In this paper, the effect of lubricating
oil on the performance of a semi-hermetic twin-screw refrigeration compressor is investigated. A mathematical
model is established and a comprehensive experimental investigation is performed for this purpose.
The model is validated using experimental data and then used to investigate the effect on
compressor performance of lubricating oil supplied to the suction and discharge end bearings, and
returned to the suction pipe. The results show that the compressor performance is reduced as the compensation
oil injection flow rate increases in the suction pipe. However, as the compensation oil injection
position moves from the suction pipe to a proper compression chamber position, the compressor efficiencies
increase as the oil flow rate increases. The results also show that the compressor performance
decreases as the oil flow rate increases at the suction end bearing. But the effect on the compressor
performance of the lubricating oil supplied to the discharge end bearing depends on the oil temperature.
Low temperature oil supplied to the discharge end bearing increases the compressor performance, while
high temperature oil lowers the compressor performance. These analyses provide useful information for
optimizing lubricating oil distribution to maximize energy efficiency in semi-hermetic twin screw