Numerical Investigations Of Flows in Axial and Radial Fans Using OpenFOAM

Abstract

In this investigation OpenFOAM is used for numerical computations of complex flows in axial and radial fans. Because of the low Mach number and small pressure differences, air is considered as incompressible. Turbulence is modeled using RANS approach, where performance of several turbulence models are tested. Both steady and unsteady computations are performed. For steady computations frozen rotor approach is used, with GGI interpolation[2] on the stator-rotor interfaces. In this case, in order to save compu- tational time, the computational domain of the rotor is one segment (blade passage) of the complete fan. At lateral boundaries, cyclic boundary condition is used. The process of determination of the characteristic curve, starting from CAD geometry of the fan, is completely automated with Python scripts. Numerical results of characteristic curve are compared with experimental measurements. For block-structured, hexahedral grid generation commercial software ICEM CFD was used. Also, OpenFOAM results are compared with results obtained with ANSYS-CFX software. For unsteady computations, complete flow domain was modeled, with relative mesh motion (i.e. rotation) in rotor domain.