Numerical study on flow characteristics of rotor pumps including cavitation

摘要

This work is purposed to study the flow characteristics of rotor pumps including cavitation. First, a simplified two-dimensional numerical model is developed and computing strategies of the numerical analysis for cavitation are set up, including the selection of cavitation model and its parameters. Second, the reliability and accuracy of the two-dimensional numerical model are verified by experimental results. Then, several factors affecting the cavitation are discussed, including the rotational speeds, pressure differences, clearance sizes, and inlet pressures. For different rotational speeds and pressure differences, the mass flow rates with cavitation are a little larger than that without cavitation, but the amplitudes of the mass flow rates with cavitation are much larger than that without cavitation. Meanwhile, the volume fraction of the water vapor increases with the increasing speeds and the decreasing pressure differences. However, compared with the influence of rotational speeds, the influence of the pressure differences on the vapor contents is relatively smaller. Regarding the clearance size, the smaller the clearance size is, the stronger the cavitation will be. Furthermore, the clearance size between two rotors has a larger effect on the cavitation than that between rotor and pump case. For inlet pressure, it has a little effect on the mass flow rates when cavitation is not considered, but it presents a remarkable effect for the model with cavitation. In addition, the peaks of the volume fractions of vapor and the mass flow rates generally offset backward with the decreasing inlet pressures.