ANALYSIS OF FLOW SEPARATION IN ANNULAR DIFFUSERS

Abstract

A diffuser is a device for converting the kinetic energy of an incoming fluid into pressure. Diffuser forms an important part in flow machinery and structures. The present study involves the CFD analysis for the prediction of effect of swirl on the flow separation. Swirling flows are very common in technical applications, especially in hydraulic machinery, and require sophisticated modeling. The annular diffuser considered in the present case has different cases i.e. parallel hub with diverging casing, both hub and casing diverging with equal angles, both the hub and casings diverging with unequal angles and hub converging but casing diverging with unequal angles. The pressure recovery coefficient at hub and casing side has also been worked out .The k-ε RNG turbulence models is studied in the present study. The analysis is done on all the four types of cases ie Straight Hub and Diverging Casing, Both hub and casing diverging with equal angles. Both hub and casing diverging with un...