Numerical Simulation of Flowfields in a Stationary Two-Pass Duct with Staggered Rounded Ribs Skewed 45-deg to the Flow

摘要

Large-eddy simulation has been applied to study fluid flow in a stationary two-pass duct with 45-deg staggered ribs. A density-based solver based on a cell-centered finite-volume method in conjunction with the preconditioning method was used to solve the ensemble-averaged Navier-Stokes equations under a Reynolds number of 10000. The time-integration scheme employed a three point backward difference method. In the space discretization, the diffusion and convection term were respectively discretized by using the second order center flux-difference splitting and the AUSMDV. The flow properties on the two sides of the cell's interface were determined by the van Leer's Kappa scheme. A minmod limiter was used to prevent numerical oscillation and raise the spatial accuracy to second-order. It is found that the predicted centerline wall-pressure distributions on the leading and trailing walls agree well with measured results. The computed pressure contours are qualitatively similar to those reported by previous researchers although the duct geometry and parameter range are somewhat different between the two studies. In addition, the critical pitch index beyond which the examined flow attains fully developed flow condition is found to be practically independent of the pass inlet velocity profile. This observation is reported for the first time and believed to provide a useful reference for CFD in this area.