Flow Behavior in a Dump Diffuser With Distorted Flow at the Inlet

Abstract

The cold flow experiments are made in a two-dimensional dump diffuser. Behavior of an impinging jet over a flame dome head and its reattachment to the casing wall is presented, when a symmetric or distorted flow is provided at the diffuser inlet. A hot-wire anemometer and laser doppler velocimeter are used. Diffuser performances of the pressure recovery and total pressure loss on three types of pre-diffuser geometry and four cases of dump gap between pre-diffuser exit and flame dome head are tested. Both pre-diffuser geometry and dump gap are dominant parameters affecting pressure recovery and total pressure loss. A small dump gap causes insufficient pressure recovery in the pre-diffuser, resulting in a loss of total pressure in the diffuser. Distribution of the flow rate to the branched channels is relatively insensitive to the inlet velocity profile with distortion, as the shift of the jet stream occurs just upstream of the flame dome head.