Effect of area ratio on flow separation in annular diffuser

Abstract

Annular diffusers are integral component of the axial flow compressor, combustion chambers and inlet portion of jet engine. In present study flow behavior inside the parallel hub and diverging casing annular diffuser having area ratio 2 to 4 with help of FLUENT has been predicted. The effect of different inlet swirl angles 0°, 7.5°, 12°, 17° and 25° has been studied to predict the reversal of flow and separation of flow from the wall. The result analysis shows that swirl enhances the pressure recovery up to a particular swirl angle and falls thereafter. It also helps in suppressing the flow separation. The effect of inlet swirl on the pressure recovery coefficient has also been figured out.