Comprehensive discussions on higher back pressure system performance with cavitation suppression using high back pressure

Abstract

As a stubborn problem of hydraulic technology, cavitation occurs in nearly every hydraulic system and causes serious associated problems. Many anti-cavitation component improvements have been done, leading to complex structures and higher manufacturing costs. Synchronously increasing the outlet or back pressure of the pump, valve and actuator may be the most straightforward way to eliminate cavitation for the entire hydraulic system. A higher back pressure system may also induces side-effects, so comprehensive discussions on higher back pressure system performance were presented in this paper. It was found that a higher back pressure system shows good effects on weakening pump outlet/inlet pressure fluctuations, shell vibration, and noise. Furthermore, simulation visualization showed consistent results for pump cavitation reduction, while with limited effects on higher back pressure conditions. With regard to pump efficiency, the higher back pressure system showed no change in the volumetric efficiency with higher back pressure, improved cavitation loss, but increased pump leakage. The mechanical efficiency rarely changed, and the detailed mechanism was much more complex. These results occurred because the higher piston chamber pressure with higher back pressure simultaneously changed the normal pressure and the lubrication property of the pump pairs. However, the system energy budget was optimistic, since considerable pressure loss from valve cavitation was prevented, although the back pressure control slippage pump added greater energy input to the system.