Numerical Calculation of the Flow in a Centrifugal Pump Impeller Using Cartesian Grid

The simulation of the three-dimensional turbulent flow in turbomachines is currently based on the solution of the Reynolds Averaged Navier Stokes equations. A considerable computational effort usually goes to the mesh generation process due to the complexity of the impeller geometry. The use of Cartesian grids combined with a numerical technique for solving partially blocked cells is presented in this work. With the proposed approach the mesh generation can be accomplished very fast and in a fully automated way. The flow equations are discretized using the control volume approach, whereas the standard k-ε model is adopted for the turbulence closure. A number of geometric variables are introduced for the parameterization of the impeller geometry allowing also for easy design modifications. The computations for the steady flow field in a particular impeller are presented and the results are analyzed with the aid of 3-dimensional graphs. Next, the characteristic performance curves for the entire load range of the impeller are constructed, and their pattern is found reasonable and in agreement with theory. Key-Words: Centrifugal pump impeller; Numerical modelling; RANS equations; Cartesian grids; Performance curves.