Experimental Study of Flow Inside a Centrifugal Fan Using Magnetic Resonance Velocimetry

Abstract

Three-dimensional (3D), three-component time-averaged velocity fields have been measured within a low-speed centrifugal fan with forward curved (FC) blades. The model investigated is representative of fans commonly used in automotive applications. The flow was analyzed at two Reynolds numbers for the same ratio of blade rotational speed to outlet flow velocity. The flow patterns inside the volute were found to have weak sensitivity to Reynolds number. A pair of counter-rotating vortices evolves circumferentially within the volute with positive and negative helicity in the upper and lower regions, respectively. Measurements have been further extended to capture phase-resolved flow features by synchronizing the data acquisition with the blade passing frequency. The mean flow field through each blade passage is presented including the jet-wake structure extending from the blade and the separation zone on the suction side of the blade leading edge.