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The effects of a three-dimensional tapered diffuser vane on the flow field and noise radiated from a centrifugalcompressor are investigated by both CFD analyses and experiments.Tapered diffuser vanes are very useful notonly for the reduction of the interaction tone noise but also for the improvement of the pressure recovery charac-teristics within the diffuser passage.By using tapered diffuser vanes,the interaction area between the impel-ler-discharge flow and diffuser vanes becomes small,and then the noise level of the discrete tone can be reducedremarkably as a result.Furthermore,by utilizing the visualization technique of vortical structures based on theCFD results,the scale of vortex shedding leaving from the leading edge of the diffuser vanes is found to be con-tracted and a tendency for the turbulence level to decrease is observed.This may be the cause of the attenuation ofbroadband noise components.The secondary flow,which is considered to be an obstruction of diffuser pressurerecovery,can also be suppressed by the tapered diffuser vanes,and the pressure decrease observed in the throatpart of the diffuser passage is further reducible.
The effects of a three-dimensional tapered diffuser vane on the flow field and noise radiated from a centrifugal compressor are investigated by both CFD analyzes and experiments. Peptide diffuser vanes are very useful not simply for the reduction of the interaction tone noise but also for the improvement of the pressure recovery charac-teristics within the diffuser passage. By using diff diffuser vanes, the interaction area between the impel-ler-discharge flow and diffuser vanes becomes small, and then the noise level of the discrete tone can be reduced remarkably as a result. Furthermore, by utilizing the visualization technique of vortical structures based on the CFD results, the scale of vortex shedding leaving from the leading edge of the diffuser vanes is found to be con-tracted and a tendency for the turbulence level to decrease is observed. This may be the cause of the attenuation of broadband noise components. the secondary flow, which is considered to be an obstruction of diffuser pressurer ecovery, can also be suppressed by the tapered diffuser vanes, and the pressure decrease observed in the throat part of the diffuser passage is further reducible.