The influence of compressor outlet conditions on the performance of annular diffusers

Experiments have been carried out on an Optimum (C •) Diffuser (Area Ratio- 2:1) to investigate the way in which compressor exit conditions influence the performance and boundary layer growth within the diffuser. Three sets of conditions simulated by 0°, 15° and 30° Radially Tilted O.G.V. (outlet guide vanes) have been studied. Compressor delivery conditions were simulated by a single Rotor row just upstream of the O.G.V. The Rotor/O.G.V. constituted a single compressor stage and was sited 0.125 blade chord lengths upstream of diffuser inlet. The diffuser static pressure recovery, total pressure loss and flow stability were, in all cases, better than that achieved with fully developed flow at inlet to the diffuser. The 30o O.G.V. configuration being the most superior [continued]…