This work aims at studying the influence of adding splitter blades on the performance of a hydraulic centrifugal pump. The studied machine is an ENSIVAL-MORET MP 250.200.400 pump (diameter = 408 mm, 5 blades, specific speed = 32), whose impeller is designed with and without splitter blades. Velocity and pressure fields are computed using unsteady Reynolds-averaged NavierStokes (URANS) approach at different flow rates. The sliding mesh method is used to model the rotor zone motion in order to simulate the impeller-volute casing interaction. The flow morphology analysis shows that, when adding splitter blades to the impeller, the impeller periphery velocities and pressures become more homogeneous. An evaluation of the static pressure values all around the impeller is performed and their integration leads to the radial thrust. Global and local experimental validations are carried out at the rotating speed of 900 rpm, for both the original and the splitter blade impellers. The head is evaluated at various flow rates: 50%, 80%, 100%, and 120% of the flow rate at the best efficiency point (BEP). The pressure fluctuations are measured at four locations at the BEP using dynamic pressure sensors. The experimental results match the numerical predictions, so that the effect of adding splitter blades on the pump is acknowledged. Adding splitters has a positive effect on the pressure fluctuations which decrease at the canal duct.

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This work aims at assessing the velocity field, pressure, and radial thrust distribution inside a centrifugal pump (ENSIVAL-MORET MP 250.200.400 pump, diameter ¼ 408 mm, five blades, specific speed ¼ 32) at various flowrates. A three-dimensional flow simulation is first presented for the isolated impeller. A three-dimensional quasi-unsteady flow simulation of the impeller -volute assembly is then performed for several impeller blades and volute tongue relative positions. The computed pressure fields enable to evaluate the radial thrust on the pump shaft and to study its variations with the flowrates. The computed pressure fluctuations match the measures obtained from 10 unsteady pressure sensors placed on the impeller shroud and volute, so that the validity of the computed radial thrust is acknowledged. Downloaded from Impeller Inlet flange radius, R 0 (mm) 115 Mean impeller inlet radius, R 1 (mm) 75 Inlet impeller width, b 1 (mm) 85.9 Inlet blade angle, b 1 (8) 7 0 Blade LE inclination angle, u 1 (8) 3 7 Mean impeller outlet radius, R 2 (mm) 204.2 Outlet impeller width, b 2 (mm) 42 Outlet blade angle, b 2 (8) 6 3 Blade TE inclination angle, u 2 (8) 9 0 Blade number, Na 5 Blade thickness, e (mm) 8Volute Base volute radius, R 3 (mm) 218 Volute width, b 3 (mm) 50 Outlet flange diameter, f outlet (mm) 200

In this article, a dynamical model of the vibrations and acoustic radiation of a circular clamped plate excited by a voice coil and two annular piezoelectric patches is derived. This model is used to perform an optimization of the geometries with the objective to minimize the vibration of the plate along its second and third modes, so that the plate's radiation is equilibrated between its first and fourth eigenfrequencies. Experiments are then performed and show a good agreement with the model. Radiation of the designed system presents improvements when compared to a system when only a voice coil is used.

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