Effect of swirl flow on characteristics of the annular diffuser

Abstract

Abstract The current work deals with the axial flow annular diffuser’s performance characteristics with divergent casing angle 9° with an area ratio of 3. We performed the numerical simulation to examine the inlet swirl’s effect on the annular diffusers. The velocity profiles were measured along the span of diffusers at a number of locations. Analysis of the results shows that the inlet swirl improves the stability at outlet flow, gains the recovery of pressure, and delays the flow separation on the casing. It is found that static pressure recovery increases by 5% with swirl flow. The results prove that the best performance is observed in the unequal hub and diverging casing diffuser with an equivalent cone angle of 15° and the inlet swirl angle of 12°.