EFFECT OF TURBULENCE INTENSITY ON FLOW CHARACTERISTICS

Abstract

Annular diffusers are often used in conjunction with turbo machines to increase the static pressure and reduce the velocity of the discharge flow. The present work involves systematic analysis of a parallel hub and diverging outer wall annular diffusers with varying values of turbulence intensity, using FLUENT CFD tool. Diffuser is tested for the inlet flow velocity of 25, 50 & 75 m/s to provide a comprehensive basis. The values of turbulence intensity are varied from 2% to 10% in each case. Flow in diffuser is observed and analyzed for changes in velocity profile, change in velocity magnitude and static pressure at casing wall and hub wall. It is observed that the static pressure does not change significantly with turbulence intensity but the velocity near casing wall increases with increase in turbulence intensity, this will cause the reduction in chances of separation