Effect of aspect ratio and curvature on characteristics of S-shaped diffusers

Performance characteristics of S-shaped rectangular diffusers have been inv estigated using CFD. The characteristics have been obtained for 15 degrees /15 degrees, 22.5 degrees /22.5 degrees, 30 degrees /30 degrees, 45 degrees /45 degrees and 90 degrees /90 degrees diffusers for constant circular cen ter line length of 600 mm having an aspect ratio of 2, 4 and 6 at inlet. It is observed that as the curvature increases, the uniformity of flow at the outlet reduces, the cross flow velocities at the outlet increase and the c oefficient of pressure recovery decreases. The effect of aspect ratio on th e performance characteristics of these diffusers is also similar, i.e. redu ction in aspect ratio reduces flow uniformity and pressure recovery.