Experimental Study on the Cavitation Characteristics of an Oil Jet Pump With Multiple Nozzles for the Lubrication System in a Steam Turbine

Abstract

Cavitation characteristics of oil jet pumps with multiple nozzles were studied using high frequency response pressure transducers with Mobile DTE Light Oil in experiment, which has an environment the same as that in the lubrication system of the steam turbine in a power plant. The influence of working oil pressure, pressure ratio, and area ratio on cavitation characteristics were studied with the area ratio ranging from 4 to 9, and the working oil pressure ranging from 1.8 to 2.8 MPa. Results show that the cavitation erosion on the throat surface is caused by the intense shear layer of highspeed jet in the throat, which leads to the collapse of vortex cavitation bubbles near the throat surface in an oil jet pump with multiple nozzles. What is more, the vortex cavitation is difficult to eradicate in an oil jet pump with multiple nozzles for the lubrication system of a steam turbine. However, there is a working point with low cavitation intensity, which is also the high efficiency point that ensures both relative safety and high efficiency. This study provides quantitative relation for the determination of working oil pressure, area ratio, and pressure ratio of an oil jet pump with multiple nozzles, which is significant for engineering.