Passages of Preceding Blade Wakes and Their Effects in the Rotor Passages of a Single Stage Axial-Flow Fan

Abstract

In this paper, three dimensional unsteady velocity were measured in the moving blade passage of a single stage axial-flow fan with a stationary blade in front of fan wheel. In order to measure three dimensional unsteady velocity distributions in the moving blade row, a specially designed hot wire traversing apparatus was used. A hot wire probe which was 45° inclined to the stem was used. In the moving blade passage, measurements were made in 6 axial positions, in 11 radial positions and in 20 circumferential positions. Rotational speeds were 600, 1500 and 2400 rpm and the opereating conditions were three points on the decreasing inclination zone on the pressure-discharge curve. Effects of secondary flow, leakage through the tip clearance on the unsteady flow phenomena in the rotor passage were discussed.