Special Topic: Reducing the Secondary Flow Losses By Endwall Contouring
The HP-turbine, in contrast to LP-turbine, has a relatively small aspect ratio which causes major secondary flow regions close to the hub and tip. As a result, the secondary flow caused by a system of hub and tip vortices that induce drag forces resulting in an increase of secondary flow losses, as extensively discussed in . Focusing on the secondary flow loss mechanisms, the fluid particles within the endwall boundary layers are exposed to a pitchwise pressure gradient in the blade channel. The particles move from the pressure side to the suction side and generate a system of vortices. These vortices induce drag forces that are the cause of the secondary flow losses. In addition, their interaction with the main flow causes angle deviation inside and outside the blade channel resulting in additional losses due to angle deviation. The nature of different flow losses is comprehensively treated in Chapter 6.
Unable to display preview. Download preview PDF.
- Schobeiri, M. T., Turbomachinery Flow Physics and Dynamic Performance, Second and Enhanced Edition, 725 pages with 433 Figures, Springer-Verlag, New York, Berlin, Heidelberg, ISBN 978-3-642-24675-3, library of congress 2012935425 published 2012Google Scholar
- Schobeiri, M. T., J. Gilarranz, and E. Johansen, ”Final Report on: Efficiency, Performance, and Interstage Flow Field Measurement of Siemens-Westinghouse HP-Turbine Blade Series 9600 and 5600,” September, 1999.Google Scholar
- Schobeiri, M. T. and K. Lu, 2013, ”Endwall Contouring Using Continuous Diffusion, a New Method and Its Application to a Three-Stage High Pressure Turbine,” ASME Transaction, Journal of Turbomachinery, also ASME GT GT2012-69069.Google Scholar
- Brennan G., N. W. Harvey, M. G. Rose, N. Fomison and M. D. Taylor, 2001, ”Improving The Efficiency of The Trent 500 HP Turbine Using Non-Axisymmetric End Walls: Part 1 Turbine Design,” Proceedings of ASME Turbo Expo 2001, 2001-GT-0444.Google Scholar
- Harvey, N. W., M. G. Rose, G. Brennan and D. A. Newman, 2002, ”Improving Turbine Efficiency Using Non-Axisymmetric End Walls: Validation in The Multi-Row Environment and with Low Aspect Ratio Blading,” Proceedings of ASME Turbo Expo 2002, GT-2002- 30337.Google Scholar
- Germain, T., M. Nagel, I. Raab, P. Schuepbach, R. S. Abhari and M. Rose, 2008, ”Improving Efficiency of a High Work Turbine Using Non-Axisymmetric End Walls Part I: Endwall Design and Performance,” Proceedings of ASME Turbo Expo 2008, GT2008-50469.Google Scholar
- Snedden, G., D. Dunn, G. Ingram and D. Gregory-Smith, 2009, ”The Application of Non-Axisymmetric Endwall Contouring in a Single Stage, Rotating Turbine,” Proceedings of ASME Turbo Expo 2009, GT2009-59169.Google Scholar
- Schobeiri, M. T., 2010, Fluid Mechanics for Engineers, Graduate Textbook, Springer-Verlag, New York, Berlin, Heidelberg, ISBN 978-642-1193-6.Google Scholar
- Schobeiri, M. T., 2014,Engineering Applied Fluid Mechanics, Graduate Textbook, McGraw Hill, January 15, 2014.Google Scholar