Use of a commercial CFD package to predict shut-off behaviour of a model centrifugal pump - an appraisal

摘要

The capability of commercial CFD packages has increased rapidly over the last few years, and the recent introduction of sliding mesh models has enabled the analysis of rotor/stator interaction problems. An outstanding problem which requires such detailed, time dependent, analysis for realistic modelling is the flow in a centrifugal pump at the shut-off condition. In this paper a commercial package is used to analyse the flow in a simplified model pump at shut-off, and the results are compared with detailed experimental measurements. The agreement is qualitatively good, and considerable insight is given into the flow mechanisms at shut-off. The CFD model over predicts shut-off head by around 25%, however, and so gives no quantitative improvement on existing correlations. These errors may be partially attributed to the restriction to first order accurate solution schemes and relatively simple k-s turbulence models imposed by the present implementation of the sliding mesh model. Consequently, solutions for geometrically simplified models, amenable to analysis without use of a sliding mesh, are also presented. It is shown that solutions are strongly dependent on the turbulence model used.