Effect of Change in the Curvature of Flow and Performance Characteristics of Straight and S-shaped Diffuser

Abstract

The effect of the change in the curvature of the stream and the execution attributes of straight walled and S-shaped rectangular diffusers having a center-length of 500 mm and an area ratio of 1.5 is studied in this paper. Straight and S-shaped diffusers with a square inlet and a rectangular outlet have been fabricated using an alternate turn angle. The cross-flow velocity, static pressure and total pressure variation along the length, at different sections of the diffusers, are measured using pressure tapings and normal three-hole probe. The low performance is due to the generation of secondary flows as a result of the geometrical curvature and the additional losses are due to the surface roughness of the diffusers. The total pressure loss coefficient for all the diffusers is nearly identical and seems to be independent of the angle of turn. In this paper, results were shown in the form of pressure recovery coefficient, coefficient of total pressure loss, average cross-flow velocity and flow deviation. Furthermore, pressure and velocity contours were developed for the entire study of all four designs of the diffuser.