Computational Fluid Dynamics, Centrifugal Fan, Multiple Reference Frame, Cut-cell method, Automatic Mesh Refinement
Computational Fluid Dynamics (CFD) is a convenient and powerful tool for modeling and evaluating the performance of centrifugal compressors, fans, and pumps. Typically, the use of CFD requires significant labor in mesh generation and refinement. Moreover, for rotating transient simulations, a grid-to-grid interface is usually needed to incorporate the rotating impeller. In this work, a finite-volume-based Cartesian cut-cell method is employed to model a centrifugal fan. Both rotating transient simulations and steady steady multiple reference frame (MRF) simulations are analyzed. The cut-cell-based method automatically generates the Cartesian mesh on-the-fly based on the current location of the rotating boundaries, without requiring any grid-to-grid interface between the rotating part and the stationary part for the rotating transient cases. The grid is also dynamically refined based on the velocity field and y-plus values at the walls. These features greatly save the pre-processing time of the modeling and make it easy for performing global grid convergence studies. The flow is validated against experiment data for both point velocity measurements, and global measurements of mass flow rate and pressure rise. Key simulation parameters and model constants that can affect the global output and local flow details are discussed.