Effects of Reynolds Number and free-stream Turbulence on Boundary Layer Transition in a Compressor Cascade

An experimental and analytical study has been performed on the effect of Reynolds number and free-stream turbulence on boundary layer transition location on the suction surface of a controlled diffusion airfoil (CDA). The experiments were conducted in a rectilinear cascade facility at Reynolds numbers between 0.7 and 3.0 310 6 and turbulence intensities from about 0.7 to 4 percent. An oil streak technique and liquid crystal coatings were used to visualize the boundary layer state. For small turbulence levels and all Reynolds numbers tested, the accelerated front portion of the blade is laminar and transition occurs within a laminar separation bubble shortly after the maximum velocity near 35‐40 percent of chord. For high turbulence levels (Tu .3 percent) and high Reynolds numbers, the transition region moves upstream into the accelerated front portion of the CDA blade. For those conditions, the sensitivity to surface roughness increases considerably; at Tu54 percent, bypass transition is observed near 7 ‐10 percent of chord. Experimental results are compared to theoretical predictions using the transition model, which is implemented in the MISES code of Youngren and Drela. Overall, the results indicate that early bypass transition at high turbulence levels must alter the profile velocity distribution for compressor blades that are designed and optimized for high Reynolds numbers. @DOI: 10.1115/1.1413471#

[1]  Mark Drela,et al.  Viscous/inviscid method for preliminary design of transonic cascades , 1991 .

[2]  R. E. Mayle,et al.  The 1991 IGTI Scholar Lecture: The Role of Laminar-Turbulent Transition in Gas Turbine Engines , 1991 .

[3]  H. Starken,et al.  Off-Design Transition and Separation Behavior of a CDA Cascade , 1996 .

[4]  Nicholas A. Cumpsty,et al.  Compressor Blade Boundary Layers: Part 2—Measurements With Incident Wakes , 1990 .

[5]  H. E. Gallus,et al.  Experimental Investigation of a Single Stage Axial Flow Compressor With Controlled Diffusion Airfoils , 1996 .

[6]  Howard P. Hodson,et al.  Boundary Layer Development in Axial Compressors and Turbines: Part 3 of 4— LP Turbines , 1997 .

[7]  Gregory J. Walker,et al.  OBSERVATIONS OF WAKE-INDUCED TRANSITION ON AN AXIAL COMPRESSOR BLADE , 1995 .

[8]  Reinhard Mönig,et al.  1999 Turbomachinery Committee Best Paper Award: Development of Advanced Compressor Airfoils for Heavy-Duty Gas Turbines— Part II: Experimental and Theoretical Analysis , 2000 .

[9]  B. J. Abu-Ghannam,et al.  Natural Transition of Boundary Layers—The Effects of Turbulence, Pressure Gradient, and Flow History , 1980 .

[10]  A. Schäffler.  Experimental and Analytical Investigation of the Effects of Reynolds Number and Blade Surface Roughness on Multistage Axial Flow Compressors , 1980 .

[11]  Reinhard Mönig,et al.  1999 Turbomachinery Committee Best Paper Award: Development of Advanced Compressor Airfoils for Heavy-Duty Gas Turbines— Part I: Design and Optimization , 2000 .

[12]  Y. Dong,et al.  Compressor Blade Boundary Layers in the Presence of Wakes , 1995 .

[13]  J. P. Gostelow,et al.  Investigations of Boundary Layer Transition in an Adverse Pressure Gradient , 1988 .

[14]  M. F. Blair.  Influence of free-stream turbulence on boundary layer transition in favorable pressure gradients , 1982 .

[15]  Reinhard Mönig,et al.  Development of Advanced Compressor Airfoils for Heavy-Duty Gas Turbines: Part I — Design and Optimization , 1999 .

[16]  J. P. Gostelow,et al.  Closure to “Discussion of ‘Investigations of Boundary Layer Transition in an Adverse Pressure Gradient’” (1989, ASME J. Turbomach., 111, p. 374) , 1989 .

[17]  D. C. Wisler,et al.  Loss Reduction in Axial-Flow Compressors Through Low-Speed Model Testing , 1985 .

[18]  Andre Mignosi,et al.  Transition analysis by surface temperature mapping using liquid crystals , 1998 .

[19]  Howard P. Hodson,et al.  Boundary Layer Development in Axial Compressors and Turbines: Part 1 of 4—Composite Picture , 1997 .