A centrifugal compressor stage with wide flow range vaned diffusers and different inlet configurations

Abstract In most cases, the diffuser system of a centrifugal compressor comes in the two general categories of a vaneless or a vaned diffuser. The vaned diffuser can generally be subdivided into two types depending on channel geometry (straight or curved channel) or depending on solidity. For the three different vaned diffusers of a centrifugal compressor stage, the design procedure is presented and experimental data are compared. The primary objective of the diffuser design was to achieve substantial improvement, compared with the stage currently used for the intended application, for the stable operating flow range as well as for the head rise from design to surge flow. The design goals also included achieving competitive efficiency levels, which required a significant efficiency improvement. Test results showed a much wider stable operating range than had been expected. This stage operated well beyond the expected vaned diffuser stall limit. The inlet configuration and inlet flow structure are known significantly to affect the compressor performance. Each of the three diffusers is tested for two different types of inlet configuration, and the relative performances are assessed.