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In this video, Kiran Dellimore introduces his research paper entitled 'Influence of a Streamwise Pressure Gradient on Film-Cooling Effectiveness' published in the JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER,Vol. 23, No. 1, January-March 2009. His co-authors are Carlos Cruz, Andre W. Marshall, and Christopher P. Cadou all from the University of Maryland, College Park, Maryland 20742. Film cooling is widely used in conventional gas turbine and rocket engines to minimize thermal loading of engine structures and to manage heat transfer between hot, reacting gases and cooler structural components. Previous experimental work has shown that streamwise pressure gradients strongly influence the performance of the film.This paper extends semi-empirical modeling ideas for wall-jet film cooling to include the effects of adverse and favorable pressure gradients. The extended model shows that a pressure gradient’s effect on cooling performance depends on whether the velocity of the film is greater than the core flow (a wall-jet film) or less than the core (a coredriven film). In wall-jet films, a favorable pressure gradient improves cooling performance by increasing the thickness and persistence of the film. Conversely, in core-driven films, a favorable pressure gradient reduces the persistence and thickness of the film leading to reduced cooling performance. Under isobaric conditions, the extended model results match experimental measurements within 2.5% in the near-slot region. When pressure gradients are present, the extended model matches experimental data to within 15% in the near-slot region and correctly predicts experimentally observed trends
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Posted by: kdellimo
25-07-11
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Film cooling references: [1] Schuchkin, V., Osipov, M., Shyy, W., and Thakur, S., “Mixing and Film Cooling in Supersonic Duct Flows,” International Journal of Heat and Mass Transfer, Vol. 45, 2002, pp. 4451–4461. [2] Bogard, D. G., and Thole, K. A., “Gas Turbine Film Cooling,” Journal of Propulsion and Power, Vol. 22, No. 2, 2006, pp. 249–270. [3] Mayhew, J., Baughn, J., and Byerly, A., “The Effect of Freestream Turbulence on Film Cooling Adiabatic Effectiveness,” International Journal of Heat and Fluid Flow, Vol. 24, 2003, pp. 669–679. [4] Pietryzk, J. R., Bogard, D. G., and Crawford, M. E., “Effects of Density Ratio on the Hydrodynamics of Film Cooling,” Journal of Turbomachinery, Vol. 112, No. 3, 1990, pp. 437–450. 259 [5] Jones, T., V., “Theory for the Use of Foreign Gas in Simulating Film Cooling,” International Journal of Heat and Fluid Flow, Vol. 20, 1999, pp. 349–354. [6] Pedersen, D., Eckert, E. and Goldstein, R., “Film Cooling with Large Density Differences between the Mainstream and the Secondary Fluid Measured by the Heat- Mass Transfer Analogy,” ASME Journal of Heat Transfer, Vol. 99, 1977, pp. 620– 627. [7] Lucas, J. G., and Golladay, R. L., “An Experimental Investigation of Gaseous Film Cooling of a Rocket Motor,” NASA TN D-1988, October 1963. [8] Hansmann, T., Wilhelmi, H. and Bohn, D., “An Experimental Investigation of the Film-Cooling Process at High Temperatures and Velocities,” AIAA Paper 93- 5062, November 1993. [9] Bons, J., Rivir, R., MacArthur, C., and Pestian, D., “The Effect of Unsteadiness on Film Cooling Effectiveness,” AIAA Paper 95-0306, January 1995. [10] Seo, H. J., Lee, J. S., and Ligrani, P. M., “The Effect Injection Hole Length on Film Cooling with Bulk Flow Pulsations,” International Journal of Heat and Mass Transfer, Vol. 41, No. 22, 1998, pp. 3515–3528. [11] Simon, F., “Jet Model for Slot Film Cooling with Effect of Free-stream and Coolant Turbulence,” NASA TP-2655, October 1986.
Posted by: kdellimo
25-07-11
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Hi Amardip, I will post some film cooling references shortly. My apologies for not responding to this sooner.
Posted by: smenon
11-10-10
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Nice video!!
Posted by: A Ghosh
02-09-10
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Nice to see you discussing your paper. If you could upload your doctoral dissertation as well that would be of great use. Could you point me to some resources in the film cooling area ? NTRS ? AIAA Electronic library ?
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