Prédiction des poches de cavitation à l'entrée d'une pompe. Comparaison calculs/expérience

Forecasting of cavitation sheets at a pump inlet. Calculations/experiment comparison

EDF, Direction des Etudes et recherches, Châtou

Abstract

By applying an integral equation method to a blade to blade calculation, an attempt is made to forecast the cavitation pocket expansion at the peripheral edges of pumps according to the NPSH function. The code, created by the CREMHyG, has been linked to a quasi-3-D calculation. A comparison with the experiment was effected on a pump-turbine model. The calculation results express in relief form the high repressing behind the pocket which extends over a zone larger than the corresponding non-cavitating depression zone. The cavity lengths obtained are, however, shorter than those observed on the model. This seems ascribable to the modelization being too constrained concerning the downstream profile pocket readherence, the fixed profile calculation showing strong sensitivity of the type of connection.