Vipin Tyagi’s research while affiliated with Shell Technology Centre Bangalore and other places

The paper discusses numerical prediction of erosion wear trends in centrifugal pump casing pumping dilute slurries. The casing geometry is considered two-dimensional. Discrete Phase Model (DPM) in FLUENT 6.1® is utilized to obtain dilute slurry flow field through the pump casing employing two-way coupling. Standard k - ε model is used for turbulence. Effect of several operational parameters viz. pump flow rate, pump speed (RPM), particle diameter and various geometry conditions viz. tongue curvature, slope of the discharge pipe and casing width is studied. Qualitative trends of erosion wear is described for these operational and geometric parameters with an idea to lower the wear rates and to make the wear pattern along the casing wall as uniform as possible. For example, with increase in pump flow rate, wear rates tends to even out whereas with increased casing width, wear rates are found to decrease.

Dense slurry flow through centrifugal pump casing has been modeled using the Eulerian-Eulerian approach with Eulerian multiphase model in FLUENT 6.1®. First order upwinding is considered for the discretization of momentum, k and ε terms. SIMPLE algorithm has been applied for dealing with pressure velocity coupling. A mixture property based k-ε turbulence model has been used for modeling turbulence. Results are validated first against mesh independence and experiments for a particular set of operational and geometric conditions. Parametric analysis is then performed to determine the effect on important physical quantities viz. solid velocities, solid concentration and solid stresses near the wall with various operational geometric conditions of the pump.

In this study, the expected particle trajectories and concentration distributions in a 2D slurry pump casing are investigated using the discrete phase modeling (DPM) module in FLUENT 6.1 ®. Two-way coupling between the carrier-phase and dispersed phase is considered. First order upwinding and segregated solver in double precision mode are adopted for the carrier phase flow field. The validation of the present study has been carried out with respect to mesh refinement and comparison of predicted trajectories with numerical results (published elsewhere) for a channel flow. The influence of operating parameters such as flow rate, pump speed, casing geometry, particle diameter and averaged particle concentration on the concentration distribution along the casing walls is examined in detail. The relevance of the computations to wear prediction is briefly discussed.