Influence of blade geometry on secondary flow development in a transonic centrifugal compressor

• Published in: Journal of the Global Power and Propulsion Society Vol. 2; no. 1; p. I1
• Main Authors: Mosdzien, Moritz, Enneking, Martin, Hehn, Alexander, Grates, Daniel, Jeschke, Peter
• Format: Journal Article
• Language: English
• Published: Global Power and Propulsion Society 27.09.2018
• Subjects: centrifugal compressor; loss reduction; measurement; numerical optimization; secondary flow; vortex development
• ISSN: 2515-3080; 2515-3080
• DOI: 10.22261/JGPPS.I1RSJ3

Due to the increasing demand for higher efficiencies of centrifugal compressors, numerical optimization methods are becoming more and more relevant in the design process. To identify the beneficial features of a numerical optimized compressor design, this paper analyses the influence of arbitrary blade surfaces on the loss generation in a transonic centrifugal compressor. The paper therefore focuses on an analysis of the secondary flow development within the impeller blade passages. To do this, steady simulations were performed on both a baseline and an optimized blade design. Two distinct design features of the optimized compressor stage were identified, which lead to a more homogenous impeller exit flow and thus to an increase in total-to-static efficiency of 1.76% points: the positive lean in the near-tip region and the positive blade curvature in the rear part of the optimized impeller. Furthermore, through extensive experimental investigations conducted on a large scale test rig it has been possible to prove the particular impeller outflow characteristics of the baseline compressor stage.