In this thesis, a numerical investigation of the flow through a return channel of a multistage, single shaft centrifugal compressor stage is presented. The simulations were conducted in advance to a measurement campaign, carried out at the Institute of Jet Propulsion and Turbomachinery. The objective of this thesis is a detailed analysis of the flow phenomena occurring in the return channel and their contribution to the total pressure losses. The compressor stage has a high range flow coefficient with accordingly wide channels. This encourages the formation of three-dimensional flow phenomena, which will be investigated in this thesis. Especially, the mixing processes of inhomogeneous flow fields within the meridional channel curvatures cause great losses. Thereby, the curvature induced turbulent effects dominate the generation of total pressure losses. Additionally, the flow profiles and the potential effects caused by the channel curvatures distinctly influence the flow through the deswirl vanes. By successively imprinting the channel curvatures on the flow filed within the deswirl vane's passage it is emphasized that both, the turning of the flow and the loss characteristic are changed significantly. The strong interactions between the different parts of the return channel make it impossible to design the parts independently from each other. A treatment of the whole return channel system is unavoidable. Furthermore, the flow field at the outlet of the diffuser has a distinct influence on the losses within the return channel.

Zugl.: Aachen, Techn. Hochsch., Diss., 2015; Aachen VII, 157 S. : Ill., graph. Darst. (2015). = Zugl.: Aachen, Techn. Hochsch., Diss., 2015

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