Cavitating flow in non-circular opening spool valves with U-grooves

Abstract

Cavitating flow in non-circular opening spool valves with U-grooves has been investigated in this article. Multifarious cavitating properties, including acoustic cavitation, morphologic cavitation, and discharge performance with cavitation, are investigated, the correlations of which are discussed. The critical opening condition in each valve is obtained based on the analysis of a throttling model. It is found that the cavitating properties show remarkable differences in the two situations when the opening is larger and smaller than the critical opening. Additionally, cavitation impacts on the discharge performance are investigated with the assistance of acoustic and visual detection.

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

“…Figure 17 shows the local minimum cavitation intensity £ Cav-min versus the working oil pressure P0 with m = 1.41. /?cav_rnin increases by e 1'91 times when P0 increases by 1 MPa, which fits a exponent relationship well in experimental range, as shown in the following equation: £ c a v -m in = 0.0305 l e L91p° -0.82021 (8) The pressure ratio of the local minimum cavitation intensity point increasing with increasing working oil pressure is caused by the extension of a low pressure region due to increasing jet veloc ity, which leads to the increase in entrainment capability and pres sure ratio. At the same time, the shear strength is enhanced with a higher jet velocity, which intensifies the bubble dynamic behavior near the wall.…”

“…Cunningham et al [1] showed cavitation in the mixing throat leads to the limiting flow pressure transducers. Lu et al [8] and Zou et al [9] proposed a quali tative relation for predicting the incipience and intensity of cavitation based on the dramatic increase in acoustic energy spectra at the onset of cavitation inception. Bourassa and Parsons [10] and Davis et al [11] investigated the cavitating flow of jet fuel in a convergingdiverging nozzle with numerical simulation and experiment, respectively.…”

“…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 …”

Non-linear dynamic modelling of a switching valve driven by pulse width modulation in the hydraulic braking system of a vehicle

“…Also, because of the fast velocity at the valve-opening port, the pressure falls to the saturated vapour pressure, leading to cavitation. 34,35 After the valve-opening port, there is also a small pressure difference between the pressure at the left-hand end of the spool and at the outlet, which is mainly caused by the fluid vortex, as shown in Figure 12(b); a hydraulic force is needed from the right-hand compressed fluid to change the direction of the flow velocity. Also, in the figure, it can be seen that the direction of the outlet flow is almost perpendicular to the axis, and so the axial velocity can be neglected.…”

Vibration characteristics of the two‐stage throttle valve induced by cavitation

“…The simulation results indicate that the pressure inside the medium chamber is not constant, but the locations of maximum and minimum pressures inside the medium chamber are both fixed, which will not vary with the passage area ratio or the inlet and outlet pressures. Lu and Zou [11] investigated cavitation flow in non‐circular opening spool valves with U‐grooves. It was found that the cavitation properties show remarkable differences in the two situations when the opening is larger or smaller than the critical opening.…”