Cross-Injection Film Cooling on a Curved Surface with or without a Vortical Flow in the Mainstream

Abstract:

Liquid crystal thermography with steady-state experimental method is used to investigate the effectiveness of two-row, cross-injection film cooling on a concave or convex surface. One leg of vortices of a delta wing is used to realize the interaction mechanism between the vortex generated by the cross-injection coolant and the secondary vortex of the main flow. The secondary flow generated by the delta-wing vortex generator produces upwash or downwash motion when sweeping over the film injection holes. In the experiments, the cooling hole diameter, hole-to-hole distances, and an included angle of 120 degrees are fixed, while the main flow Reynolds number, sense of mainstream vortex, and the coolant-to-main flow blowing ratio are varied. Because the cross-injection coolant generates a counter-clockwise vortex (viewed from upstream), results show that when the mainstream vortex has a sense of rotation opposite to that of the cross-injection vortex (i.e. an upwash mainstream vortex), the effectiveness is increased. On the other hand, same sense of rotation in both vortices (i.e. a downwash mainstream vortex) decreases the effectiveness. Both the convex and concave curvatures hamper the attachment of cross-injection coolant to the surface, resulting in a reduction in film cooling effectiveness. The effect is more influential for the concave surface.

• Periodical: Defect and Diffusion Forum (Volume 336)
• Pages: 39-45
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.336.39
• Online since: March 2013
• Authors: Pey Shey Wu, Kun Yu Chen, Yi Hung Lin
• Keywords: Curved Surface, Film Cooling, Liquid Crystal Thermography, Vortex Generator

References

[1] C.A. Hale, M.W. Plesniak, and S. Ramadhyani: J. Turbomachinery Vol. 122 (2000), pp.553-557.

[2] L.S. Langston: ASME J. Engineering for Power Vol. 102 (1980), pp.866-874.

[3] O.P. Sharma and T.L. Butler: J. Turbomachinery Vol. 109 (1987), pp.229-236.

[4] R.A. Graziani, M.F. Blair, J.R. Taylor, and R.E. Mayle: ASME J. Eng. for Power Vol. 102 (1980), pp.257-267.

[5] R.J. Goldstein and R.A. Spores: J. Heat Transfer Vol. 110 (1988), pp.862-869.

[6] R.J. Goldstein and P.H. Chen: J. Eng. for Gas Turbines and Power Vol. 107 (1985), pp.117-122.

[7] R.J. Goldstein and P.H. Chen: J. Turbomachinery Vol. 109 (1987), pp.588-593.

[8] T.W. Simon and J.D. Piggush: AIAA J. Propulsion and Power Vol. 22 (2) (2006), pp.301-312.

[9] R.J. Moffat: Experimental Thermal and Fluid Science Vol. 1 (1988), pp.3-7.