Author(s): Sofiane Benhamadouche; Wadih J. Malouf; Mario Arenas
Keywords: Orifice plate; Discharge coefficient; RANS; Grid convergence index
Abstract: The orifice plate is a pressure differential device commonly used for flow measurements in pipes. The present study demonstrates the accuracy that can be obtained with computational fluid dynamics (CFD) to predict the pressure loss and discharge coefficient for a flow through a square-edged orifice in a round pipe at a Reynolds number equal to 25000. The computations simulate an experimental set-up with detailed particle image velocimetry (PIV) .Sensitivity studies are carried out using different mesh refinements and Reynolds averaged Navier-Stokes (RANS) turbulence models. The grid convergence index (GCI) is used to estimate the spatial discretisation error for global values, while the turbulent models are compared to the ISO 5167-2 standards. Eddy viscosity models and Reynolds stress models with near-wall modelling show significant sensitivity to the mesh refinement with standard two velocity scales wall functions. However, the elliptic blending Reynolds stress model (EB-RSM) with a resolution down to the wall exhibits less sensitivity to the mesh refinement.