Performance of Gas Turbine Film Cooling with Backward Injection

X. C. Li, G. Subbuswamy, J. Zhou

Department of Mechanical Engineering, Lamar University, Beaumont, Texas, USA.

DOI: 10.4236/epe.2013.54B025                

Abstract

Gas turbines have been widely used in power generation and aircraft propulsion. To improve the gas turbine performance, the turbine inlet temperature is usually elevated higher than the metal melting point. Therefore, cooling of gas turbines becomes very critical for engines’ safety and lifetime. One of the effective methods is film cooling, in which the coolant air from the discrete holes blankets the surface from the hot gas flow. The major issues related to film cooling are its poor coverage, aerodynamic loss, and increase of heat transfer coefficient due to strong flow mixing. To improve the cooling performance, this paper examined film cooling with backward injection. It is observed that film cooling with backward injection can produce much more uniform cooling coverage under different conditions, which include cases on flat surface with low or high pressure and temperature. The backward injection also performs better in the presence of blade curvature. The effect of other parameters on the film cooling is also reported. The numerical results are validated by simple experimental test in this study.

Keywords

Film Cooling; Cooling Effectiveness; Backward Injection

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	R. J. Goldstein, “Film Cooling,” Advances in Heat Transfer, Vol. 7, 1971, pp. 321-379. doi:10.1016/S0065-2717(08)70020-0
[2]	R. J. Goldstein, E. R. G. Eckert and F. Burggraf, “Effects of Hole Geometry and Density on Three-dimensional Film Cooling,” International Journal of Heat and Mass Transfer, Vol. 17, No. 5, 1974, pp. 595-607. doi:10.1016/0017-9310(74)90007-6
[3]	M. Gritsch, W. Colban and K. Dobbeling, “Effect of Hole Geometry on the Thermal Performance of Fan- Shaped Film Cooling Holes,” ASME Journal Turbomachinery, Vol. 127, No. 4, 2005, pp. 718-725. doi:10.1115/1.2019315
[4]	H. H. Cho, D. H. Rhee and B. G. Kim, “Enhancement of Film Cooling Performance Using a Shaped Film Cooling Hole with Compound Angle Injection,” JSME International Journal, Ser B, Vol. 44, 2001, pp. 99-107.
[5]	R. A. Brittingham and J. H. Leylek, “A Detailed Analysis of Film Cooling Physics: Part IV - Compound-Angle Injection with Shaped Holes,” ASME Journal Turbomachinery, Vol. 122, No. 1, 2000, pp.133-145. doi:10.1115/1.555419
[6]	V. L. Eriksen and R. J. Goldstein, “Heat Transfer and Film Cooling Following Injection through Inclined Circular Tubes,” ASME Journal of Heat Transfer, Vol. 96, No. 2, 1974, pp. 239-245. doi:10.1115/1.3450171
[7]	R. Jia, B. Sunden, P. Miron and B. Leger, “Numerical and Experimental Investigation of the Slot Film Cooling Jet with Various Angles,” Journal Turbomachinery, Vol. 127, No. 3, 2005, pp. 635-645. doi:10.1115/1.1929821
[8]	R. E. Mayle, F. C. Kopper, M. F. Blair and D. A. Bailey, “Effect of Stream-line Curvature on Film Cooling,” ASME Journal of Engineering for Power, Vol. 99, No. 1, 1977, pp. 77-82. doi:10.1115/1.3446255
[9]	S. Na and T. I-P. Shih, “Increasing Adiabatic Film- Cooling Effectiveness by Using an Upstream Ramp,” ASME Jounal of Heat Transfer, Vol. 129, No. 4, 2007, pp. 464-471. doi:10.1115/1.2709965
[10]	Y. Lu, A. Dhungel, S. V. Ekkad and R. S. Bunker, “Effect of Trench Width and Depth on Film Cooling from Cylindrical Holes Embedded in Trenches,” Journal of Turbomachinery, Vol. 131, 2009, pp. 011003- 011113.
[11]	X. Li and T. Wang, “Simulation of Film Cooling Enhancement with Mist Injection,” ASME Journal of Heat Transfer, Vol. 128, No.6, 2006, pp. 509-519. doi:10.1115/1.2171695
[12]	X. Li and T. Wang, “Computational Analysis of Surface Curvature Effect on Mist Film Cooling Performance,” Journal Heat Transfer, Vol. 130, 2008, pp. 121901-1219 10.
[13]	X. Li, “Numerical Simulation on Fluid Flow and Heat Transfer of Film Cooling with Backward Injection,” Proceedings of 14th Internatinal Heat Transfer Conference, Washington DC, 2010, pp. 257-265.