Simulation of the work process of a two-stage pump with a first-stage hydraulic drive

Abstract

This article describes a method of CFD-modeling of a two-stage high-pressure pump. The main feature of the pump is the hydraulic drive of the low-pressure stage that takes energy from a high-pressure flow. The speed of the turbine is determined by the power balance of a low-pressure rotor. The modeling technique presented in this paper includes two major advantages over previous studies. The first feature is the determination of the speed of rotational velocity during the CFD-calculation by a special methodology. The second feature is cavitation simulation to assess its impact on the pre-pump workflow at a relatively low inlet pressure. Recommendations for the use of software (ANSYS CFX, NUMECA AutoGrid5, ANSYS ICEM CFD) are an important part of the simulation technology described. These recommendations concern the choice of the modeling area, mesh generation, choice of turbulence models, verification of convergence, post-processing of the results. The adequacy of the CFD-model was evaluated by comparing the calculated and experimental performance obtained on a test rig. The use of the resulting methodology of pump simulation improves the productivity and increases the efficiency of pumps with a hydro-drive of the low-pressure stage.

Keywords

• two-stage pump
• cfd-modeling
• hydro-drive
• cavitation
• stage matching