Research on Cavitation Characteristics and Influencing Factors of Herringbone Gear Pump

Abstract

Cavitation is a common issue in pumps, causing a decrease in pump head, a fall in volumetric efficiency, and an intensification of outlet flow pulsation. It is one of the main hazards that affect the regular operation of the pump. Research on pump cavitation mainly focuses on mixed flow pumps, jet pumps, external spur gear pumps, etc. However, there are few cavitation studies on external herringbone gear pumps. In addition, pumps with different working principles significantly differ in the flow and complexity of the internal flow field. Therefore, it is urgent to study the cavitation characteristics of external herringbone gear pumps. Compared with experimental methods, visual research and cavitation area identification are achieved through computation fluid dynamic (CFD), and changing the boundary conditions and shape of the gear rotor is easier. The simulation yields a head error of only 0.003% under different grid numbers, and the deviation between experimental and simulation results is less than 5%. The study revealed that cavitation causes flow pulsation at the outlet, and the cavitation serious area is mainly distributed in the meshing gap and meshing area. Cavitation can be inhibited by reducing the speed, increasing the inlet pressure, and changing the helix angle can be achieved. For example, when the inlet pressure is 5 bar, the maximum gas volume fraction in the meshing area is less than 50%. These results provide a reference for optimizing the design and finding the optimal design parameters to reduce or eliminate cavitation.