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.

Optimal design and numerical analysis of multi-field coupling in a screw pump under wet gas compression

“…In this paper, the traditional screw pump described in Ref. 17 is optimized by using a decompressive variable-pitch screw rotor to solve the problems due to wet gas compression. The profile of the end face of the twin screws is fixed, but the screw pitch and thread width are gradually reduced from the inlet to the discharge along the axial direction.…”

“…The profile equation of the screw end face and the helix equation of a variable-pitch screw are introduced below. According to Ref., 17 the end face of a screw-pump rotor is a double cycloid, as shown in Figure 2 .…”

“…The clearance between the rotor and the liner is 0.3 mm, the flank clearance of the screw rotors is 0.5 mm, and the clearance between the screw tooth top and tooth root is 0.25 mm. According to Ref., 17 the thickness of the liner is 20 mm. In SOLIDWORKS, the screw section profile is generated first, and then the helix is drawn according to the above equations.…”

“…The temperature, pressure, and deformation of a rotor in an oil-free air compressor were calculated and analyzed by computational fluid dynamics software. Based on fluid–structure thermal coupling, Zhang et al 17 analyzed the influence of high GVF on the comprehensive deformation of a rotor and liner and the volumetric efficiency of a twin-screw pump. They determined the optimal installation clearance.…”

Optimizing the Clearance Fit of a Progressive Cavity Pump for the Thermal Recovery of Petroleum Using Fluid–Structure Thermal Coupling

“…The deformation of the stator is simplified as a fluid–structure coupling process. − The influence of thermodynamic factors is neglected, the stator is regarded as a deformable body, and multifield coupling software is used to realize unidirectional fluid–structure coupling between the liquid and the stator.…”