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 o f oil je t 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 o f the steam turbine in a power plant. The influence o f 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 o f high-speed je t in the throat, which leads to the collapse o f vortex cavitation bubbles near the throat surface in an oil je t pump with multiple nozzles. What is more, the vortex cavitation is difficult to eradicate in an oil je t pump with multiple nozzles fo r the lubrication system o f 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 fo r the determination o f working oil pressure, area ratio, and pres sure ratio o f an oil je t pump with multiple nozzles, which is significant fo r engineering.

A Novel Approach for Identifying Gas Cavitation in Oil Jet Pump for Lubrication System

“…These data suggest that moderate gas cavitation is able to decrease cavitation intensity in oil jet pump. More explanation can be found in a previous study [30]. Compared to the throat vibration, the high frequency noise is absent from the local maximum point.…”

“…The measured performance of the oil jet pump includes entrainment, efficiency, cavitation erosion ability, vibration, and noise. In these parameters, the entrainment, efficiency and cavitation erosion ability are quantified with entrainment ratio q, efficiency η, cavitation intensity E [30]. Their expressions are shown in Eqs.…”

Influence of inlet pressure on cavitation characteristics in regulating valve

“…Therefore, the high-velocity zone has the tendency of radial expansion and the velocity gradient between the valve seat and the center of the flow passage increases. This larger velocity gradient enhances the shear strength, the maximum of the vapor volume fraction becomes larger (Zhang et al, 2014), and the cavitation strengthens with increasing input pressure. When P in = 2.1 MPa, no cavitation can be found, and the vapor volume fraction equals 0.…”

“…The literature has focused on the characteristics of flow with different operating conditions, but few reports exist on the cavitation characteristics in regulating valves used in direct coal liquefaction. Only a few papers (Zheng, Ou, & Jin, 2017; reported the cavitation erosion of high-pressure letdown valve. They investigated cavitation-flow-induced valve spool failure, and a cavitation flow test rig was developed to observe cavitation on the valve model.…”

Experimental investigation of the flow characteristics of jet pumps for zero flow-ratio conditions

“…The jet pump suction chamber has low pressure that can lead to cavitation [6] . Cavitation in jet pumps can reduce the efficiency and damage the transported material and the system stability and safety [7][8][9][10] . However, some studies have noted that there are many potential applications of cavitation in jet pumps due to the mechanical, physical and chemical effects, such as in fuel systems [11] , soil reclamations [12] , sewage treatments [13] , chemical and pharmaceutical processes [14] .…”