Numerical Study on the Application of Overset Mesh Method for Rotating Impellers Using OpenFOAM

Abstract

Intermeshing rotors exist in various applications, such as kneaders and extruders, and their performance could be assessed using computational fluid dynamics simulations. It is essential to evaluate the robustness and accuracy of such simulations. Here, we apply the overset mesh method to simulate intermeshing rotors using a Newtonian fluid to assess the suitability of the method. First, the simulations of concentric cylinders were used to evaluate the effect of three numerical approaches. Second, the simulations of a rotating impeller were applied to study five different mesh topologies. Finally, two intermeshing impellers were simulated to demonstrate the functionality of the overset mesh method, and the conservation of transported scalar was evaluated. All cases were simulated using the OpenFOAM open-source software. The general observations were: 1) The simulated velocity fields were in good accordance with the reference cases and the passive scalar was conserved in the simulation case of intermeshing impellers despite the inherent mass conservation errors. 2) However, fluctuations in power number were detected for conformal meshes in the two impeller case.