Dynamic Simulation Research on Cavitation in Internal Multi-connected Volumes of Gear Pump

In order to perform fast action of actuator, a large flow rate of hydraulic pump is needed. High speed operation of gear pump becomes one of the most effective ways to reach large flow rate of gear pump in a finite volume. However, high speed rotation can easily result in air is absorbed into gear pump, which exacerbating the cavitation of gear pump. In order to study the dynamic evolution of gas phase during the cavitation in gear pump and analyze the coupling relationship between air and other dynamic behavior, this study established a fluid dynamics model of the multi-connected volumes inside gear pump. Meanwhile, we used the method of computational fluid dynamics and the full cavitation theory to simulate the instantaneous state of cavitation in the multi-connected volumes inside gear pump at different rotation speeds and different suction pressure. The results indicated that: at different rotational speeds and different suction pressures, different degrees of cavitation will occur in internal multi-connected volumes of gear pump; with the increase of rotational speed or the decrease of suction pressure, the maximum vapor volume fraction and cavitation degree of flow filed in gear pump will increase; with the cavitation increasing, the flow state of gear pump becomes more and more unstable, which reduces the continuity and stability of gear pump’s outlet flow.