Numerical Study on Rotor Deformation of Multiphase Twin-Screw Pumps Under High Gas Volume Fraction Conditions
Twin-Screw Pump, Screw Deformation, Leakage Gap, Gas Volume Fraction
Multiphase pumping with twin-screw pumps is a relatively new technology that has been proven successful in a variety of field applications. It has three advantages such as less environment pollution, few separation equipments and more convenient operation than the conventional system. Despite many advantages of this technology, some problems have been encountered when operating under conditions with high gas volume fractions (GVF). While twin-screw multiphase pump is operating under high GVF conditions, the inner temperature of the pump increases obviously. The clearances between rotors change greatly and influence the volumetric efficiency of the twin-screw multiphase pumps. In some severe conditions, it may cause the pump damage. In this paper, the actual force and thermal boundary conditions are proposed through further investigations of pressure distributions and heat transfer. And then the screw rotor deformation and temperature field are calculated under different GVF conditions with ANSYS software. The results indicate that the main deformation of screw rotors is thermal deformation and the maximum radial deformation occurs on the top of the rotor in the discharge port. Through analyzing the influence of screw rotor deformation on the clearance, it can be realized that the greatest clearance changes are in the root of the rotor, followed by circumferential clearance, and there is no changes in flank clearance.