Effect of swirl flow on the performance of parallel hub axial annular diffuser
In the present work, the performance characteristics of the parallel hub axial flow annular diffuser with divergent casing varying between equivalent cone angle (10°, 15°, and 20°) with area ratio 3 has been evaluated computationally as well as experimentally. The performance of three diffusers were tested at different inlet swirl angles (from 0° to 25°) for swirling and non-swirling flow. Simulations have been carried out on a fully developed flow at Reynolds number 2.5×105. The results were analyzed based on the velocity profile, static pressure recovery coefficient, and the total pressure loss coefficient. The result analysis shows that the inlet swirl flow improves the recovery of pressure and also delays the flow separation on the casing. The results show that better performance is observed in the case of parallel hub diverging casing with equivalent cone angle 10° and inlet swirl angle of 7.5° in comparison to other diffusers.