Abstract
In this paper, we revealed a factor causing the remarkably large amplitude delivery-pressure oscillation with quite low frequency, occurring often in pressure-compensated variable displacement vane pumps under deadhead conditions. It was found experimentally and theoretically that the pump instability originates in the fact that the gradient, ∂A/∂E is significantly negative, where A is time-averaged effective area for the internal pressure compensation force and E is the cam ring eccentricity. Also this phenomenon is regarded as same as surging of the turbo-fan.
