Lightweight High-Pressure Ratio Centrifugal Compressor for Vehicles-Investigation of Pipe Diffuser Designs by Means of CFD

Authors: Eleni Ioannou, Pascal Nucara, Keith Pullen

Abstract:

The subject of this paper is the investigation of the best efficiency design of a compressor diffuser applied in new lightweight, ultra efficient micro-gas turbine engines for vehicles. The Computational Fluid Dynamics (CFD) results are obtained utilizing steady state simulations for a wedge and an ”oval” type pipe diffuser in an effort to identify the beneficial effects of the pipe diffuser design. The basic flow features are presented with particular focus on the optimization of the pipe diffuser leading to higher efficiencies for the compressor stage. The optimised pipe diffuser is designed to exploit the 3D freedom enabled by Selective Laser Melting, hence purposely involves an investigation of geometric characteristics that do not follow the traditional diffuser concept.

Keywords: CFD, centrifugal compressor, micro-gas turbine, pipe diffuser, SLM, wedge diffuser.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1123701

References:

[1] D. Japikse, Centrifugal Compressor Design and Performance, Concepts ETI Inc. 452 p., Vermont, USA, 1996.
[2] D. Kenny, Supersonic Radial Diffusers, AGARD Lecture Series, Vol. 39 VKI, Brussels, Belgium, 1970.
[3] P. M. Came, The Current State of Research and Design in High Pressure Ratio Centrifugal Compressors, Procurement Executive, Ministry of Defence, Aeronautical Research Council, C. P. No. 1363, 1977.
[4] D. R. Grates, P. Jeschke, R. Niehuis, Numerical Investigation of the Unsteady Flow Inside a Centrifugal Compressor Stage with Pipe Diffuser, Journal of Turbomachinery, Vol. 136, pp. 031012-1-13, 2014.
[5] D. S. Krige, Performance Evaluation of a Micro Gas Turbine Centrifugal Compressor Diffuser, Master Thesis, Stellenbosch University, March 2013.
[6] G. Pavesi, Impeller Volute and Diffuser Interaction, Design and Analysis of High Speed Pumps, Science and Technology Organisation, RTO-EN-AVT-143, pp. 6-1- 6-28, 2006.
[7] J. Schiff, A Preliminary Design Tool for Radial Compressors, Master Thesis, Lund University, Sweden, June 2013.
[8] M. Casey, D. Rusch, The Matching of a Vaned Diffuser with a Radial Compressor Impeller and Its Effect on the Stage Performance, Proceedings of ASME Turbo Expo, GT2014-25003, Dusseldorf, Germany, June 16-20, 2014.
[9] W. W. Clements, D. W. Artt, The Influence of Diffuser Vane Leading Edge Geometry on the Performance of a Centrifugal Compressor, ASME Gas Turbine and Aeroengine Congress and Exposition, 89-GT-163, Toronto, Ontario, Canada, June 4-8, 1989.
[10] R. H. Aungier, Centrifugal Compressors: A Strategy for Aerodynamic Design and Analysis, ASME Press 328 p., ISBN: 9780791800935, 2000.
[11] T. Jiang, T. T. Yang, Improved Vane-Island Diffusers at High Swirl, ASME, 82-GT-68, 1982.
[12] E. Benini, A. Toffolo, A. Lazzaretto, Experimental and Numerical Analyses to Enhance the Performance of a Microturbine Diffuser, Experimental Thermal and Fluid Science, Vol.30 (5), pp. 427-440, 2006.
[13] M. Olivero, Evolution of a Centrifugal Compressor, from Turbocharger to Micro Gas Turbine Applications, Doctoral Thesis, Technical University of Delft, Netherlands, 2012.
[14] G. Han, X. Lu, Sh. Zhao, Ch. Yang, J. Zhu Parametric Studies of Pipe Diffuser on Performance of a Highly Loaded Centrifugal Compressor, Journal of Engineering for Gas Turbines and Power, Vol.136 (12), 122604-1-10, 2014.
[15] G. B. Reeves, Design and Performance of Selected Pipe-Type Diffusers, ASME, 77-GT-104, 1977.
[16] I. Bennett, A. ourlidakis, R. L. Elder The Design and Analysis of Pipe Diffusers for Centrifugal Compressors, Proceedings of the Institution of Mechanical Engineers, Vol.214 (1), pp. 87-96, 2000.
[17] V. G. Filipenco, S. Deniz, J. M. Johnston, E. M. Greitzer, N. A. Cumpsty Effects of inlet flow field conditions on the performance of centrifugal compressor diffusers: Part 1Discrete-passage diffuser, Journal of Turbomachinery, Vol.122 (1), pp. 1-10, 2000.
[18] M. Inoue, N. A. Cumpsty Experimental Study of Centrifugal Impeller Discharge Flow in Vaneless and Vaned Diffusers, Journal of Engineering for Gas Turbines and Power, Vol.106 (2), pp. 455-467, 2009.
[19] N. N. Mansour, J. Kim, P. Moin Near-Wall k−ε Turbulence Modeling, AIAA Journal, Vol.27 (8), pp. 1068-1073, 1989.