Numerical model for simulation of pump-intake flow and vortices

This paper describes the development of a computational fluid dynamics model to simulate the three-dimensional flow field in a pump intake and to study the formation of free-surface and wall-attached vortices. The model solves the Reynolds-averaged Navier-Stokes equations and two turbulence-model equations in generalized curvilinear coordinates using a fully implicit, fractional-step algorithm based on alternate direction implicit approximate factorization. A two-layer k-epsilon turbulence model is employed to resolve the near-wall flow that is critical to the description of wall-attached vortices. Solutions at a Reynolds number of 60,000 for flow in a simple rectangular sump are presented to demonstrate the use of the numerical model to predict the location and strength of free-surface and wall-attached vortices. As the case study was selected according to commonly used design criteria, relatively weak vortices are predicted. The predicted complex vortex structure is analyzed. The test case suggests that the numerical model may be employed with other geometrical arrangements and flow parameters to study their effect on the intake flow structure and vortices in pump sumps.