Numerical Simulation and Validation of Dilute Gas-Particle Flow Over a Backward-Facing Step

摘要

The physical characteristics of dilute gas-particle flows over a backward-facing step geometry are investigated.An investigation is performed to assess the performance of two computational approaches-the Lagrangian particle-tracking model and Eule-rian two-fluid model-to predict the particle phase flow parameters under the influence of different particle inertia.Particles with corresponding diameters of 1 /xm(small-size particles)and 70 mum(large-size particles)are simulated under the flow condition of two Reynolds numbers(based on the step height):Re = 15000 and Re = 64000,for which the model predictions are compared against benchmark experimental measurements.Among the various turbulence models evaluated,the RNG kappa-epsilon and realizable kappa-epsilon models provided better agreement with the experimental data for the range of particles considered.The Eulerian approach used in this study combines an overlapped technique with a particle-wall collision model to better present the particle-wall momentum transfer than traditional Eulerian models.In comparing to the Lagrangian and Eulerian approaches for particle flow predictions,the latter was shown to yield closer agreement with the measured values.