MULTISTAGE CENTRIFUGAL-PUMPS: ASSESSMENT OF A MIXING PLANE METHOD FOR CFD ANALYSIS

An accurate CFD investigation allows a thorough knowledge of the fluid dynamic field inside a multistage centrifugal pump but only a correct interpretation of its results grants a well-founded prediction of the machine performance curves. The paper introduces the assessment of an improved methodology to predict head-flow and efficiency characteristics of industrial pumps in real operating conditions. The described approach is based on standard CFD analysis and experimental tests. The numerical procedure is built-up of three different steps: • CFD investigation of the single impeller and diffuser domains; • impeller-diffuser interaction analysis; • evaluation of the whole multistage pump performance curves by pressure field interpretation and taking into account real machine secondary phenomena. The stage computational model is made up of two 3D fluid domains with overlapping: one of them is aimed to simulate the diffuser and is related to a stationary reference frame while the other one models the impeller and is referred to a rotating system. Moreover the impeller–diffuser interaction is studied by the employment of a mixing plane technique. Numerical results are then compared to the real pump performance test at the actual working conditions in order to validate the proposed methodology. The paper will discuss all approach details and the main CFD features involved. Symbols