Abstract
This paper investigates the effects of flow-interaction between a rotor and a high-resistance medium (HRM) on both rotor and system performance within the 2D cascade limit using computational fluid dynamics (CFD). Two configurations were studied: the Rotor/HRM configuration, where the HRM is located downstream of the rotor, and the HRM/Rotor configuration, where the HRM is located upstream of the rotor. The results indicate that fan performance increases from the interaction effect, along with an extension of the stall margin. However, the pressure drop across the HRM is increased due to an increase in velocity magnitude and non-uniformity, which can lower system overall performance. In the HRM/Rotor configuration, the presence of an upstream close-coupled HRM induces a high-velocity jet around the blade which is more significant on the suction surface and appears to delay flow separation, resulting in an extension of the stall margin. In the Rotor/HRM configuration, the boundary-layer thickness on the blade surfaces is reduced, resulting in delaying stall. In both cases, flow non-uniformity and the presence of swirl velocity in the HRM increases the pressure loss across it.
