With the ever-expanding demand for high-altitude reconnaissance aircraft, there has been recent increased interest in the low Reynolds number performance of turbine blading for jet engines. Several Air Force studies have focussed on boundary layer transition and separation, and overall flow characteristics and losses, at high turbulence intensity over the wide range of Reynolds numbers encountered in achieving high-altitude flight (BBBR1995, BBVB2001, VSKBBR2002). There are however experimental difficulties at ultra low Reynolds numbers and it is helpful to perform computational analysis in support of the experimental and design studies. This web page presents results of computations for the Langston turbine cascade (LNH1977, GBTM1980) over a wide range of conditions, including those considered in the Air Force studies. The calculations use the newly developed MARV Reynolds stress turbulence model (MM2006). The results show a range of flow separation characteristics in the form presented by Hourmouziadis (H1989), together with loss coefficients and deviation angles, for blade Reynolds numbers (inlet velocity and axial chord) from 3000 to 709,000, at an inlet turbulence intensity of 9%, in the form shown by Sharma et al. (SNT1994) and Rivir (R1996).
References (in chronological order)
Langston, L.S., Nice, M.L., and Hooper, R.M., 1977, "Three-Dimensional Flow Within a Turbine Cascade Passage," Journal of Engineering for Power, Vol. 99, pp. 21-28.
Graziani, R.A., Blair, M.F., Taylor, J.R., and Mayle, R.E., 1980, "An Experimental Study of Endwall and Airfoil Surface Heat Transfer in a Large Scale Turbine Blade Cascade," Journal of Engineering for Power, Vol. 102, pp. 257-267.
Hourmouziadis, J., 1989, "Aerodynamic Design of Low Pressure Turbines," AGARD Lecture Series No. 167, Blading Design for Axial Turbomachines.
Sharma, O.P., Ni, R.H., and Tanrikut, S., 1994, "Unsteady Flows in Turbines - Impact on Design Procedure," AGARD Lecture Series No. 195, Turbomachinery Design Using CFD.
Baughn, J.W., Butler, R.J., Byerley, A.R., and Rivir, R.B., 1995, "An Experimental Investigation of Heat Transfer, Transition and Separation on Turbine Blades at Low Reynolds Number and High Turbulence Intensity," ASME Paper No, 95-WA/HT-25.
Rivir, R.B., 1996, "Transition on Turbine Blades and Cascades at Low Reynolds Numbers," AIAA Paper No. 96-2079.
Butler, R.J., Byerley, A.R., Van Treuren, K., and Baughn, J.W., 2001, "The Effect of Turbulence Intensity and Length Scale on Low-Pressure Turbine Blade Aerodynamics," International Journal of Heat and Fluid Flow, Vol. 22, pp. 123-133.
Van Treuren, K., Simon, T., von Koller, M., Byerley, A.R., Baughn, J.W., and Rivir, R.B., 2002, "Measurements in a Turbine Cascade Flow Under Ultra Low Reynolds Number Conditions," Journal of Turbomachinery, Vol. 124, pp. 100-106.
Moore, J.G., and Moore, J., 2006, Functional Reynolds Stress Modeling , Pocahontas Press, Blacksburg, Virginia.
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