The influence of gas volume fractions on deformation and volumetric efficiency of twin-screw multiphase pump based on fluid-thermal-structure coupling numerical calculation

Abstract

The twin-screw multiphase pump shows a significant phenomenon of fluid-thermal-structure physics field coupling. The method of studying dynamics, thermodynamic characteristics, and deformation of the screw pump is biased from the actual boundary conditions without considering multi-field coupling. To enhance the calculation accuracy of the twin-screw pump integrated deformation field and further determine the clearances between rotors and pump liner, the fluid-thermal-structure coupling calculation is completed by ANSYS WORKBENCH. The calculation results of the leakage rate are verified by experiments. The moving reference frame dynamic mesh method is used in the fluid domain numerical simulation, and the non-equilibrium wall function method is used to solve the boundary layer. The rotor and pump liner deformations and their influences on volumetric efficiency are studied under different gas volume fractions. The optimal installation clearances are proposed to reduce the leakage flow rate and prevent the rotor from sticking due to large deformation. The results show that the calculated results of the leakage rate are in good agreement with the experimental values, and the average deviation is less than 4%. The research program effectively ensures the calculation accuracy and efficiency of the whole model and provides an important basis for the optimal design of the twin-screw pump.