A computational flow analysis of an ideal vortex-controlled diffuser (VCD) was carried out. The simulation model used is the compressible Reynolds averaged Navier-Stokes equations(RANS), with the application of the RNG based k-ε turbulence model. The effects of important parameters like static pressure recovery, bleed fraction, position of bleed slot, have been studied and comparisons were made with respect to VCD without the bleed configuration and the following features were revealed: radial profiles of velocity at the inlet, mid-planes and exit planes, including diffuser effectiveness (i.e. static pressure recovery), diffuser efficiency, reattachment length and diffuser total pressure loss. Results obtained by applying the RNG turbulence model show an instantaneous improvement in the diffuser efficiency that happens at reasonably minimal suction rates. From the calculations, it has been verified and shown in the analysis that the effect of the bleed positioning offers advantages in relation to where it is located.
Adkins RC, Matharu DS, Yost JO. The hybrid diffuser. ASME Technical Paper 1980;80-GT-136.
Adkins RC. A short diffuser with low pressure loss. J Fluids Eng.1975;97(3):297-302.
ANSYS CFX solver theory guide. Release 14. ANSYS Inc. Canonsburg 2011.
Chakrabarti S, Rao S, Mandal DK. Numerical simulation of the performance of a sudden expansion with fence viewed as a diffuser in low Reynolds number regime. J Eng Gas Turbines Power. 2010;132(11):114502.
Cockrell DJ, Markland E. A review of incompressible diffuser flow: a reappraisal of an article by G. N. Patterson entitled ‘Modern diffuser design’ which was published in this journal twenty‐five years ago. Aircr Eng Aerosp Tec. 1963;35(10):286-292.
Ghose P, Datta A, Mukhopadhyay A. Effect of prediffuser angle on static pressure recovery in flow through casing-liner annulus of a gas turbine combustor at various swirl levels. J Thermal Sci Eng. Appl. 2016;8(1):1-7.
Gorla RSR, Khan AA, Turbomachinery: Design and theory. 1st ed. CRC Press, Taylor and Francis Group. Boca Raton 2003.
Heskestad G. A suction scheme applied to flow through sudden enlargement. J Basic Eng. 1968;90(4):541-552.
Heskestad G. An edge suction effect. AIAA J. 1965;3(10):1958-1961.
Heskestad G. Further experiments with suction at a sudden enlargement in a pipe. J Basic Eng. 1970;92(3):437-447.
Klein A. Characteristics of combustor diffusers. Prog Aerosp Sci. 1995;31(3):171-271.
Lefebvre AH, Ballal DR. Gas turbine combustion. Alternative fuels and emissions. 3rd ed. CRC Press, Taylor and Francis Group. New York 2010.
Mandal DK, Bandyopadhyay, Chakrabarti S. A numerical study on the flow through a plane symmetric sudden expansion with a fence viewed as a diffuser. Int J Eng Sci Tech. 2011;3(8):210-233.
Mandal DK, Manna NK, Bandyopadhyay S, Biswas BP, Chakrabarti S. A numerical study on the performance of a sudden expansion with multisteps as a diffuser. Int J Appl Mech. 2011;3(4):779-802.
Schäfer F, Breuer M, Durst F. The dynamics of the transitional flow over a backward-facing step. J Fluid Mech. 2009; 6233:85-119.
Versteeg HK, Malalasekera W. An introduction to computational fluid dynamics. 2nd ed. Pearson. Prentice Hall, Glasgow 1995.
White FM. Viscous fluid flow. 3rd ed. McGraw Hill. New York 1974.
Wilcox DC. Turbulence modelling for CFD. 3rd ed. DCW Industries. California 2006.
Xing F, Su H, Chan S, Xu L, Yu X. Optimization study of the dump diffuser in gas turbine to reduce pressure loss. Int J Aerospace Eng. 2018;1-14.