Abstract: A problem of gas cavitation existing in the operation of axial piston pump is addressed. The current models of evaluating the fluid properties (density, bulk modulus) commonly used in lumped parameter pump models do not consider the dynamic characteristics of gas cavitation. For this reason, a novel cavitation model which accounts for the dynamic characteristics of gas (free air and vapor), including gas evolution, and transport and distribution of gas between connected control volumes, is proposed. The model is integrated in a lumped parameter axial piston pump model, and the cavitation effects are investigated. The simulated results show that the proposed method has an advantage over the classic fluid models which tend to underestimate the effect of cavitation on the outlet flow and pressure of pump. The increase in outlet flow or pressure oscillation and the reduction in average flow rate in cavitating pump are due to the change of fluid compressibility induced by air release.

Key words: ordnance science and technology, cavitation, gas evolution, axial piston pump, bulk modulus, fluid property