Experimental study on multi-stage gas-liquid booster pump for working fluid pressurization

To improve the performance of organic Rankine cycle (ORC) system, this paper proposes to replace the electric working fluid pump with multi-stage gas-liquid booster pump which is driven by high pressure gas generated in evaporator of ORC system. This pump consists of four gas-liquid booster pumps. The working principle of gas-liquid booster pump and multi-stage gas-liquid booster pump are introduced respectively. By using high pressure air as driving force and water as pressurized working fluid, the performance of multi-stage gas-liquid booster pump is tested experimentally. The experimental results of this study mainly consist of two parts: the first part focuses on the pump performance with various pressure at pump inlet and outlet while valve at pump inlet is completely open; the second part focuses on various valve open ratio at pump inlet which is operated at fixed inlet and outlet pressure of 1.8 MPa and 0.15 MPa. The results show that the pump conversion efficiency decreases with the increase of inlet pressure and the decrease of outlet pressure. The maximum conversion efficiency, volume flow rate of water and volume flow rate of high pressure air are 0.72, 0.55 L/s and 0.42 L/s respectively. When the pump is operated at different valve open ratio, the volume flow rate of water and high pressure air decreases with the decrement of valve open ratio. In addition, the conversion efficiency almost maintains identical under different valve open ratio.