Parametric Analysis of Jet Pump Performance Under Varying Diameter Ratios using Numerical Method

Abstract

The results of a numerical study of the hydrodynamics of several geometries of jet pumps (using COMSOL Multiphysics) are presented in this paper. Finite element modelling principles were used to construct a model for the analysis of the effect of the nozzle outlet diameter (d 0 ) and the diffuser outlet diameter (d 2 ) on the internal flow behaviour. Two cases were considered: d 0 =10 mm and d 2 =40 mm, and d 0 =15 mm and d 2 =50 mm. The simulations were completed with a specified inlet pressure of 101325 Pa and with the effect of gravity included. The velocity and pressure distributions at certain monitoring locations along with the entire jet pump domain were determined. It was determined that the geometric variant has a substantial effect on the development of the jet, behaviour of entrainment, and the recovery of pressure within the pump. The flow reached a steady state quickly after a short period of transients for both variants. The larger diameter variant provided larger velocities at several monitoring locations and a greater negative pressure region, thus providing greater suction and different momentum exchange. This study indicated that the diameter ratio is the most important factor for the performance of jet pumps and therefore will assist in the design of effective and optimal jet pump systems.