Abstract：Within Collaborative Research Center (SFB) 561 “Thermally Highly Loaded, Porous and Cooled Multi-Layer Systems for Combined Cycle Power Plants” at RWTH Aachen University, an effusion-cooled multi-layer plate configuration is investigated numerically by the application of a three-dimensional in-house fluid flow and heat transfer solver, CHTflow. CHTflow is a conjugate code, which yields information on the temperature distribution in the solid body. This enables a detailed discussion of the effects of a change in materials. The geometrical set-up and the fluid flow conditions derive from modern gas turbine combustion chambers and bladings. Within the SFB, two different multi-layer systems, one consisting of substrate made of CMSX-4 (a single-crystal super-alloy), an MCrAlY-bondoat and a ZrO2 thermal barrier coating (TBC), and the other consisting of a NiAl-alloy and a graded bondcoat/TBC, have been investigated. The grading will increase the life-span of the TBC as it can better compensate the different thermal expansion coefficients of different materials. The main focus in this study is on the different substrate materials, because the thermal conductivity of the NiAl is considerably higher than that of CMSX-4, which leads to different temperature profiles in the components. The numerical grid for the simulations contains the coolant supply (plenum), the solid body for the conjugate calculations, and the main flow area on the plate. The effusion-cooling is realized by finest drilled shaped holes with a diameter of 0.2mm. The investigation is concentrated on a cooling hole geometry with a laterally widened fan-shaped outlet, contoured throughout, and one without lateral widening that is only shaped in the TBC-region of the system. Two blowing ratios, M=0.28 and M=0.48, are investigated, both for a hot gas Mach number of 0.25. The results for the lower blowing ratio and the fully contoured hole are discussed as well as those of the higher blowing ratio and the non-laterally widened hole. These represent two characteristic cases.
. Numerical investigation of the effectiveness
of effusion cooling for plane multi-layer systems with different base-materials[J]. Front. Energy, 2009, 3(4): 406-413.
Dieter BOHN, Robert KREWINKEL. Numerical investigation of the effectiveness
of effusion cooling for plane multi-layer systems with different base-materials. Front. Energy, 2009, 3(4): 406-413.
Kercher D M. A film-cooling CFD bibliography: 1971―1996. International Journal of Rotating Machinery, 1998, 4(1): 61―72 doi: 10.1155/S1023621X98000062
Bunker R S. A review of shaped hole turbine film-cooling technology. Journal of Heat Transfer, 2005, 127(4): 441―453 doi: 10.1115/1.1860562
Bergeles G, Gosman A D, Launder B E. The prediction of three-dimensional discrete-hole coolingprocesses. Journal of Heat Transfer, 1976, 98: 379―386
McGovern K T, Leylek J H. A detailed analysis of filmcooling physics, Part III: Streamwise injection with shaped holes. ASME 97-GT-271, 1997
Garg V K. Heat transfer on a film-cooled rotating blade. ASME 99-GT-44, 1999
Heidmann J D, Rigby D L, Ameri A A. A 3D coupled internal/external simulation of a film-cooledgas turbine. ASME 99-GT-186, 1999
Fottner L, Ganzert W. Aerodynamische Optimierungder Kühlluft-Ausblasekonfigurationen fortschrittlicher Turbinenbeschaufelungen. Informations-tagung der FVV, Frankfurt a M, 2000
Kasagi N, Hirata M, Kumada M. Studies of full-coverage film cooling, Part 1: Coolingeffectiveness of thermally conductive wall. ASME 81-GT-37, 1981
Kumada M, Hirata M, Kasagi N. Studies of full-coverage film cooling, Part 2: Measurementof local heat transfer coefficient. ASME 81-GT-38, 1981
Bazdidi-Tehrani F, Andrews G E. Full-coverage discrete holefilm cooling, investigation of the effect of variable density ratio. Journal of Engineering for Gas Turbines and Power, 1994, 116(3): 587―596 doi: 10.1115/1.2906860
Scrittore J J, Thole K A, Burd S W. Investigation of velocity profiles for effusion coolingof a combustor liner. ASME GT-2006-90532, 2006
Arcangeli L, Surace M, Tarchi L, et al. Correlative analysis of effusion cooling systems. ASME GT-2006-90405, 2006
Bohn D, Bonhoff B, Schönenborn H, et al. Validation of a numerical modelfor the coupled simulation of fluid flow and diabatic walls with applicationto film-cooled turbine blades. VDI-Berichte, 1995, 1186: 259―272
Bohn D, Schönenborn H, Bonhoff B, et al. Prediction of the film-coolingeffectiveness in gas turbine blades using a numerical model for thecoupled simulation of fluid flow and diabatic walls. ISABE95―7105, 1995
Bohn D, Moritz N. Numerical study on innerhole shaping of full coverage cooled multi-layer plates. ISROMAC-10-2004-143, 2004
Bohn D, Ren J, Kusterer K. Conjugate heat transfer analysis for film cooling configurationswith different hole geometries. ASME GT-2003-38369, 2003
Heidmann J D, Kassab A J, Divo E A, et al. Conjugate heat transfer effects on a realisticfilm-cooled turbine vane. ASME GT-2003-38553, 2003
York W D, Leylek J H. Three-dimensional conjugateheat transfer simulation of an internally-cooled gas turbine vane. ASME GT-2003-38551, 2003
Bohn D, Moritz N. Influence of hole shapingof staggered multi-hole configurations on cooling film development. AIAA-Paper 2000―2579, 2000
Schmatz M A. Three-dimensional Viscous Flow Simulations Using an Implicit RelaxationScheme. Notes on Numerical Fluid-Mechanics(NNFM), Brunswick: Vieweg, 1988, 22: 226―242
Eberle A, Schmatz M A, Bissinger N. Generalized Flux vectors for hypersonic shock-capturing. AIAA-Paper 90―0390, 1990
Baldwin B S, Lomax H. Thin layer approximationand algebraic model for separated turbulent flows. AIAA-paper78―257, 1978
Bohn D, Moritz N. Numerical parametric studyon full coverage cooled multi-layer plates. IGTC2003-TokyoTS-084, 2003
Bohn D, Krewinkel R. Effects of concave and convexcurvature on the cooling effectiveness of effusion cooled multi-layerplates. In: Papailiou K D, Martelli F, MannaM, eds. Proceedings of the 7th EuropeanTurbomachinery Conference, Athens. 2007, 967―977
Bohn D, Krewinkel R, Rakut C. Proposing a novel approach in power plant design: Thecombined calculation of power plant processes and component stress. ISROMAC12-2008-20008, 2008
