The design and optimization of a multistage radial compressor vaneless diffuser, cross-over and return channel is presented. An analytical design procedure for 3D blades with prescribed load distribution is first described and illustrated by the design of a 3D return channel vane with leading edge upstream of the cross-over. The analysis by means of a 3D Navier–Stokes solver shows a substantial improvement of the return channel performance in comparison with a classical 2D channel. Most of the flow separation inside and downstream of the cross-over could be avoided in this new design. The geometry is further improved by means of a 3D inverse design method to smooth the Mach number distribution along the vanes at hub and shroud. The Navier–Stokes analysis shows a rather modest impact on performance but the calculated velocity distribution indicates a more uniform flow and hence a larger operating range can be expected. The impact of vane lean on secondary flows is investigated and further performance improvements have been obtained with negative lean.

Thygesen, R., 2000, “Optimization of Return Channel Blades for Radial Compressors,” von Karman Institute PR 2000–21, Sint-Genesius-Rode, Belgium.
Meng, S. Y., and Jackson, E. D., 1983, “The continuous Diffusion Crossover System Design,” ASME FED-Vol. 3, Return Passages of Multistage Turbomachinery.
Casey M., and Wintergerste T., 2000, “Best Practice Guidelines,” Ercoftac Special Interest Group on “Quality and Trust in Industrial CFD,” Ercoftac.
Sorokes, J., and Kopko, J., 2001, “Analytical and Test Experiences Using a Rib Diffuser in a High Flow Centrifugal Compressor Stage,” ASME 2001-GT-0320.
Ardizzon, G., and Pavesi, G., 2003, “Influence of the Stator/Rotor Interaction on Reverse Flow at Off-design Operation,” Proceedings of 5th European Conference on “Turbomachinery Fluid Dynamics and Thermodynamics,” Prague, pp. 619–628.
Lenke, L. J., and Simon, H., 1998, “Numerical simulation of the flow through the return channel of Mutltistage Centrifugal Compressors,” ASME 98-GT-255.
Lakhsminayarana, B., 1996, “Fluid Dynamics and Heat Transfer of Turbomachinery,” Wiley, New York.
Van den Braembussche, R. A., 1990, “Design and Optimization of Centrifugal Compressor,” von Karman Institute CN 141, Sint-Genesius-Rode, Belgium.
Rothstein, E., 1984, “Experimentelle und Theoretische Untersuchung der Stro¨mungsvorga¨nge in Ru¨ckfu¨rkana¨len von Radialverdichterstufen insbesondere solchen mit geringen Kanalbreite,” Ph.D. thesis, RWTH Aachen, Germany.
Simon, H., and Rothstein, E., 1983, “On the Development of Return Passages of Multistage Centrifugal Compressors,” ASME FED-Vol. 3, Return Passages of Multistage Turbomachinery.
Demeulenaere, A., 1997, “Conception et development d’une methode inverse pour la generation d’aubes de turbomachines,” von Karman Institute, Ph.D thesis, Sint-Genesius-Rode, Belgium.
, and
Van den Braembussche
R. A.
, “
Three-dimensional Inverse Method for Turbomachinery Blading Design
ASME J. Turbomach.
, pp.
Veress, A., 2001, “Inverse Design on Return Flow Channel for Multistage Radial Compressor,” von Karman Institute PR 2001–27, Sint-Genesius-Rode, Belgium.
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