Theoretical and experimental study of a synchronal rotary multiphase pump at very high inlet gas volume fractions

Theoretical and experimental analyses are performed to investigate the pumping behaviour of a synchronal rotary multiphase pump (SRMP) at very high inlet gas volume fractions (GVFs). A comprehensive SRMP model is developed to predict the pump performance at very high inlet GVFs, including the steady-state behaviours and the transient distributions of interesting variables during pump operation. The experimental work is implemented using N32 oil and air as the working fluids to measure the global performance parameters of the SRMP at the inlet GVFs of 91-98% and different differential pressures. The SRMP model is validated by comparison of the simulated and experimental results. The results show that the inlet GVF has a significant effect on the pump behaviour. At a given differential pressure, the leakage loss increases dramatically with the inlet GVF, which results in a significant decrease in the volumetric flow rate of the SRMP. Because of the large proportion of shaft power wasted by the high-pressure back flow, the SRMP exhibits lower pump efficiency at the higher inlet GVFs.