OPTIMIZATION OF INLET SWIRL FOR PRESSURE RECOVERY COEFFICIENT

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 pressure recovery of the diffuser. 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 both the hub and casings are diverging with casing angle keep constant as 25°. It is coded as diffuser D type. The characteristic quantities such as static pressure distribution at hub and casing walls, velocity profiles at various sections and flow patterns have been presented for studying. k-􀄰 RNG turbulence models is studied in the present study. The result indicates that pressure recovery increases with increases in area ratio. Results also shows that pressure recovery by the diffuser increases with swirl up to a limit and then it start decreasing. This optimum limit was found out to be 12° swirl intensity