Numerical and experimental evaluation of the time-variant flow field in a single-blade centrifugal pump

Abstract

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.

In this contribution the time-variant flow in a single-blade pump is evaluated by numerical and experimental methods. In a numerical approach the three-dimensional, viscous, unsteady flow field in the complete pump has been achieved by solving the unsteady Navier-Stokes equations (URANS) with different commercial solvers in a wide range of pump operation. From the calculated periodic flow field the hydrodynamic forces resulting from the time-variant pressure field and viscous stresses were determined for a complete impeller revolution. To validate the results of the numerical simulations a test rig was used to conduct some measurements in the pump. First of all the velocity field inside the pump was investigated by using the Particle Image Velocimetry. A good agreement between the velocity fields obtained by numerical simulations and by measurements has been achieved. In a second step the transient hydrodynamic forces of the pump were measured by acquisition of the appropriate forces acting on the bearings of the pump rotor during operation. The measurements of the hydrodynamic forces match the results of the numerical simulations very well. In particular, the good qualitative agreement suggests that predicting the transient flow in (single-blade) centrifugal pumps utilizing a Navier-Stokes (URANS) solver, is a reliable method to determine the time-variant hydrodynamic forces, which are decisive for the vibrations of the pump.