OpenFOAM Based Numerical Simulation of Flow Field in Rotating Curved Duct

The behavior of fluid flow in a centrifugal turbomachinery impeller is strongly influenced by the centrifugal force caused by the curvature of the impeller passage and the Coriolis force induced by rotation. Consequently,secondary flow is generated by the combined effects of centrifugal and Coriolis forces and it may induce separation of the boundary layers. Therefore,secondary flow gives an adverse impact on the performance of centrifugal turbomachinery. The application of an open-source CFD codes package OpenFOAM to the prediction of the flow field within a rotating 90°bend duct is presented. At the same time,the effects of Coriolis and centrifugal forces on the velocity,pressure and the development of secondary flow are analyzed according to the numerical results. The analysis result shows that the profile of secondary flow becomes asymmetric due to Coriolis force caused by rotation which is different to the static situation and vortex structures within the duct become more complex. In particular,the direction of the secondary flow may be reversed at higher rotational strengths.