Modares Mechanical Engineering

Modares Mechanical Engineering

Experimental Investigation of Film Cooling Effectiveness Applying a Novel Integrated Compound Jets Design for the Jet Holes

Authors
Mahdi Ramezanizadeh 1
Younes Pouladrang 2
1 Aerospace Engineering Department, Shahid Sattari Aeronautical University of Science and Technology
2 Graduate Center, Shahid sattari Aeronautical University of Science and Technology, Tehran, I.R. Iran
Abstract
Several factors such as shape of the jet hole, blowing ratio, density ratio, mainstream turbulence intensity, and …, affect the film cooling effectiveness. Among the above mentioned factors, the film cooling effectiveness is strongly influenced by the shape of the jet hole. This geometry should be designed in such a way to minimize the jet's vertical momentum and produce more surface coverage. In this research, cooling performance of a novel integrated compound (earring) jets design is investigated experimentally, using an infrared thermography method. Steady state heat transfer experiments at the jet Reynolds number of 10,000 (based on the jet diameter) are performed over the test plate. The jets injection angle into the mainflow are considered to be 30 degrees relative to the surface. The measurements are carried out at the mainstream speed of 27 m/s and at four different blowing ratios of 0.4, 0.5, 0.7, and 0.8. The obtained results show that at constant jets cross section, the earing jets geometry leads to higher film cooling effectiveness, compared to the cylindrical hole geometry. Optimum blowing ratio is 0.8 and the lowest effectiveness is obtained on the surface at the blowing ratio of 0.4. The flow structures which are introduced by this novel geometry, reduces the flow mixing between the mainstream and the cooling jets. Therefore, enhances the film cooling effectiveness and the coolant fluid more uniformly distributes over the surface laterally.
Keywords
Film cooling effectiveness
Novel jet hole geometry
Integrated compound (Earring) jets
experimental test
infrared thermography
[1] M. Vajargah, N. H. Salimi, M. Taeibi-Rahni, Numerical simulation of film cooling around a gas turbine blade via partially averaged navier-stokes approach (PANS), Amirkabir Journal Mechanical Engineering, Vol. 48, No. 3, pp. 267–280, 2016. (in Persian فارسی(
[2] M. J. F. Bazdidi-Tehrani, S. M. Mousavi, Investigation of film cooling on model turbine blade leading edge using DES and LES approaches, Modares Mechanical Engineeering, Vol. 15, No. 8, pp. 260–270, 2015. (in (فارسی Persian
[3] K. Lee, K. Kim, Shape optimization of a fan-shaped hole to enhance filmcooling effectiveness, International Journal of Heat and Mass Transfer, Vol. 53, No. 15, pp. 2996–3005, 2010.
[4] F. Bazdidi-Tehrani, N. Bohlooli, M. Jadidi, Influence of film cooling jet inlet boundary condition on large eddy simulation of model turbine blade leading edge, Computational Fluid Dynamics, Vol. 15, No. 4, pp. 214–227, 2015.
[5] R. S. Bunker, A Review of shaped hole turbine film cooling technology, Journal of Heat Transfer, Vol. 127, No. 4, pp. 441–453, 2005.
[6] M. G. Ghorab, Film cooling effectiveness and heat transfer analysis of a hybrid scheme with different outlet configurations, Applied Thermal Engineering, Vol. 63, No. 1, pp. 200–217, 2014.
[7] S. Ramesh, D. Gomez, S. V Ekkad, M. Anne, Analysis of film cooling performance of advanced tripod hole geometries with and without manufacturing features, International Journal of Heat and Mass Transfer, Vol. 94, No. 3, pp. 9–19, 2016.
[8] J. C. Han, Recent studies in turbine blade cooling, International Journal of Rotating Machinary, Vol. 10, No. 6, pp. 443–457, 2004.
[9] S. Baldauf, A. Schulz, S. Wittig, High-resolution measurements of local heat transfer coefficients from discrete hole, Journal of Turbomachinary, Vol. 123, No. 4, pp. 749–757, 2001.
[10] R. Farhadi-Azar, M. Ramezanizadeh, M. Taeibi-Rahni, M. Salimi, Compound triple jets film cooling improvements via velocity and density ratios: large eddy simulation, Journal of Fluids Engineering, Vol. 133, No. 3, pp. 31202/1-31202/13, 2011.
[11] M. R. Salimi, M. Ramezanizadeh, M. Taeibi-Rahni, R. Farhadi-Azar, Film cooling effectiveness enhancement applying another jet in the upstream neighbor of the main jet-using LES approach, Journal of Applied Fluid Mechanics, Vol. 9, No. 1, pp. 33–42, 2016.
[12] J. D. Heidmann, S. Ekkad, A Novel antivortex turbine film-cooling hole concept, Journal of Turbomachinary, Vol. 130, No. 3, pp. 31020/1-31020/9, 2008.
[13] A. Dhungel, Y. Lu, W. Phillips, E. Srinath V, H. James, Film cooling from a row of holes supplemented with antivortex holes, Journal of Turbomachinary, Vol. 131, No. 2, pp. 21007/1-21007/10, 2009.
[14] C. Leblanc, D. P. Narzary, Film cooling performance of antivortex hole on a flat plate, Journal of Turbomachinary, Vol. 135, No. 6, pp. 61009/1- 61009/11, 2013.
[15] R. J. Moffat, Describing the uncertainties in experimental results, Experimental Thermal Fluid Science, Vol. 1, No. 1, pp. 3–17, 1988.
[16] S. A. Lawson, K. A. Thole, Effects of simulated particle deposition on film cooling, ASME, Vol. 133, No. 2, pp. 21009/1-21009/9, 2011.
[17] M. Kunze, S. Preibisch, K. Landis, A New test rig for film cooling experiments on turbine endwalls, ASME, Turbo Expo 2008: Power for Land, Sea, and Air, American Society of Mechanical Engineers, Fairfield, NJ, pp. 989–998, 2008.
[18] B. Johnson, W. Tian, K. Zhang, H. Hu, An experimental study of density ratio effects on the film cooling injection from discrete holes by using PIV and PSP techniques, International Jounal of Heat and Mass Transfer, Vol. 76, pp. 337–349, 2014.
[19] B. T. An, J. J. Liu, C. Zhang, S. J. Zhou, Film cooling of cylindrical hole with a downstream short crescent-shaped block, Journal of Heat Transfer, Vol. 135, No. 3, pp. 31702/1-31702/9, 2013.
[20] A. K. Sinha, D. G. Bogard, M. E. Crawford, Film cooling effectiveness downstream of a single row of holes with variable density ratio, Journal of ASME Turbomachinary, Vol. 113, No. 3, pp. 442–449, 1991.
[21] A. P. Rallabandi, J. Grizzle, J. Han, Effect of upstream step on flat plate film cooling effectiveness using PSP, Journal of ASME Turbomachinary, Vol. 133, No. 4, pp. 41024/1-41024/8, 2011.
[22] M. Ramezanizadeh, Large eddy simulation of film cooling using different subgrid scale models, PhD Thesis, Department of Mechanical Engineering, Sharif University of Technology,Tehran, 2007. (in Persian فارسی(
Modares Mechanical Engineering
Volume 18, Issue 3
May 2018
Pages 302-310