A New High-Precision Solver to Predict Pressure Fluctuations in Centrifugal Pumps

The appearance of CFD codes in the field of Turbomachines has made a valuable contribution in understanding various physical phenomena and in improving the design of the pump. Thus, the application of numerical simulations combined with experimental tests has allowed to improve efficiency and to reduce manufacturing costs. In some industrial applications, the noise from the pumps during their operation should be reduced to respect certain acoustic criteria. One cause of this noise is the strong interactions between the rotating and stationary parts that generate pressure fluctuations within the flow which are propagated inside the machine and then toward to the environment. On the other hand, the research efforts to reduce these fluctuations concern mainly geometrical modifications (radial gap, splitter blades, volute shape) that have been tested through numerical and experimental tests. Nowadays, the requirements in terms of precision lead us to develop new and original techniques to model the fluid physics inside the pump. So, the accurate prediction of the pressure fluctuations is very sensitive and many considerations are essential for this purpose such as the correct choice of the boundary conditions, turbulence model, mesh quality and discretization schemes. For the current CFD codes, it is very difficult to achieve derivation schemes with very high order of accuracy for unsteady cases. This paper presents a new high order finite volume method to calculate the pressure fluctuations which is based on Moving Least Squares approximations. The navier-stokes solver is validated in a 2D centrifugal pump geometry and compared firstly to numerical results from Fluent code and secondly to experimental results in order also to analyze the relation between 2D and 3D pressure fluctuations.