An Initial Approach to the Design of Very Wide Angle Axisymmetric Diffusers With Gauzes to Achieve Uniform Outlet Velocity Profiles

Abstract

A method is presented of designing very wide angle axisymmetric diffusing ducts which achieve uniform outlet velocity profiles. The aim was to concentrate the major part of the diffuser pressure rise on a small portion of the duct boundary with zero or favorable pressure gradients on the remainder of the boundary. With an optimum location and design of gauze the diffusers are capable of giving a very uniform outlet velocity profile in a short overall length, when working with thin inlet boundary layers and some, although recognizably moderate, pressure recovery. One diffuser tested (diffuser C) produced uniform outlet velocity profiles in approximately 1.5 inlet diameters compared with the 10 diameters required for a sudden enlargement having comparable performance.