EXPERIMENTAL AND NUMERICAL ESTIMATION OF PERFORMANCE CHARACTERISTICS OF A CENTRIFUGAL It SLURRY PUMP HANDLING ASH WATER SLURRIES

Abstract

Centrifugal slurry pumps are generally used for hydraulic transportation of solids. The performance of the pump handling solid-liquid mixtures is normally estimated based on its performance with water and available correlations. The aim of the present work is to numerically evaluate performance characteristics of a centrifugal slurry pump handling bottom ash slurries at different solid concentrations. A commercial computational fluid dynamics (CFD) code ANSYSCFX is used to numerically simulate the three-dimensional, steady, incompressible, and turbulent solid-liquid two-phase flow using Eulcrian -Eulerian model for two phase flow and two-equation k-c turbulence model. The coupling between rotating impeller and stationary domain of volute/inlet casing was implemented by means of frozen rotor method in which the influences of rotation and curvature were taken into account. Flow pattern inside the pump section has been visualized by CFD simulation. Initially numerical simulation of flow inside slurry pump was carried out with water only and then modelled for solid-liquid mixtures. The simulation results show close agreement with experimental data for water at four different speeds. The results which are obtained from simulation preliminarily reveal the flow field of solid-liquid slurry flow in the centrifugal slurry pump which can be useful for improvement in the design of centrifugal slurry pump.