Numerical Simulation of Coolant Variation in Laminar Supersonic Film Cooling

Windisch, Christian; Reinartz, Birgit; Mueller, Siegfried

doi:10.2514/6.2012-949

Cited by 8 publications

(6 citation statements)

References 9 publications

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“…Film cooling in a laminar supersonic boundary-layer flow with foreign-gas injection has been investigated experimentally by Hombsch and Olivier [12] and numerically by Windisch et al [5]. A comparison of these results with our NS3D results for air, carbon dioxide, argon, and helium injection is shown in Fig.…”

Section: Comparison Of Foreign Cooling-gas Injection With Experimementioning

confidence: 63%

“…The experiments are conducted for various blowing rates in the range 0.010 ≤ F ≤ 0.120 at an inclination angle of α 45 deg. The numerical investigations by Windisch et al [5] are performed at F 0.05 and α 45 deg. The figure shows that the numerical results are in very good agreement.…”

Section: Comparison Of Foreign Cooling-gas Injection With Experimementioning

confidence: 99%

“…The consequence is a larger blowing momentum that scales linearly with v for constant ρv. Note that the numerical investigations by Windisch et al [5] were obtained by the finitevolume solver QUADFLOW, neglecting thermal diffusion. The latter becomes important for gas pairings with strongly differing gas properties such as helium and air; see Sec.…”

Section: Comparison Of Foreign Cooling-gas Injection With Experimementioning

confidence: 99%

“…The first procedure is simply known as film cooling. Here, the coolant is injected through a single spanwise slit or row of holes, either by blowing in the (inclined) wall-normal direction (see, e.g., [2][3][4][5][6]) or by wall-parallel blowing through a backward-facing step (see, e.g., [7][8][9][10][11]). When blowing through multiple, uniformly distributed, discrete holes or slits, this is labeled effusion cooling; see, e.g., [12][13][14].…”

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confidence: 99%

“…In addition, foreign-gas transpiration cooling at subsonic [15,18], supersonic [17], and hypersonic [16] flow conditions gives similar results. The good cooling performance of helium or hydrogen is commonly explained by their high heat capacity [7,[17][18][19] and low density (or low molar mass) [5,15,16], with the latter resulting in a thicker and thus more protective cooling film at a constant given blowing rate [5,10]. Alternatively, their high viscosity and diffusion coefficient and low molar mass are held responsible [12].…”

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confidence: 99%

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Influence of Cooling-Gas Properties on Film-Cooling Effectiveness in Supersonic Flow

Keller

Kloker

Olivier

2015

Journal of Spacecraft and Rockets

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Film cooling is considered a prerequisite for the safe operation of future high-performance rocket engines. Wallnormal or inclined cooling-gas injection into a laminar boundary-layer airflow at Mach 2.6 through a single infinite spanwise slit with various cooling gases using direct numerical simulations and experiments are investigated. Among the investigated gases, helium and hydrogen perform best with respect to cooling effectiveness and skin friction decrease. An arbitrary variation of various cooling-gas parameters shows that the diffusion coefficient has virtually no influence on the cooling effectiveness, whereas low cooling-gas viscosity, low thermal conductivity, high heat capacity, low molar mass, and low density are highly beneficial. In light of this large number of parameters, an extension of the single-species cooling-effectiveness correlation to binary gas-mixture flows is challenging, if possible at all. Nomenclature C = Chapman-Rubesin factor c = mass fraction c f = skin friction coefficient c p = heat capacity at constant pressure c v = heat capacity at constant volume D = ordinary diffusion coefficient D T = thermal diffusion coefficient e = internal energy F = blowing rate I = identity matrix j = diffusion mass-flux vector k = Boltzmann constant L = characteristic length M = molar mass Ma = Mach number Pr = Prandtl number p = pressure q = heat-flux vector R = gas constant Re u = unit Reynolds number Re ∞ = global Reynolds number Sc = Schmidt number T = temperature t = time v = velocity vector X = mole fraction x s = slit position x, y, z = streamwise, spanwise, and wall-normal directions α = blowing angle or thermal diffusion rate η = cooling effectiveness ϑ = thermal conductivity κ = specific heat ratio μ = dynamic viscosity ξ = correlation parameter ϵ = second Lennard-Jones parameter ρ = density σ = first Lennard-Jones parameter Ω = transport collision integral Subscripts c = cooling-gas values (species 2) i = species i is = isothermal uc = uncooled w = values at wall ∞ = freestream values (species 1) Superscripts = Eckert values ⋆ = dimensional values

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Section: Comparison Of Foreign Cooling-gas Injection With Experimementioning

confidence: 63%

Section: Comparison Of Foreign Cooling-gas Injection With Experimementioning

confidence: 99%

Section: Comparison Of Foreign Cooling-gas Injection With Experimementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Influence of Cooling-Gas Properties on Film-Cooling Effectiveness in Supersonic Flow

Keller

Kloker

Olivier

2015

Journal of Spacecraft and Rockets

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Numerical simulation of transpiration cooling through porous material

Dahmen

Gotzen

Müller

et al. 2014

Numerical Methods in Fluids

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SUMMARYTranspiration cooling using ceramic matrix composite materials is an innovative concept for cooling rocket thrust chambers. The coolant (air) is driven through the porous material by a pressure difference between the coolant reservoir and the turbulent hot gas flow. The effectiveness of such cooling strategies relies on a proper choice of the involved process parameters such as injection pressure, blowing ratios, and material structure parameters, to name only a few. In view of the limited experimental access to the subtle processes occurring at the interface between hot gas flow and porous medium, reliable and accurate simulations become an increasingly important design tool. In order to facilitate such numerical simulations for a carbon/carbon material mounted in the side wall of a hot gas channel that are able to capture a spatially varying interplay between the hot gas flow and the coolant at the interface, we formulate a model for the porous medium flow of Darcy–Forchheimer type. A finite‐element solver for the corresponding porous medium flow is presented and coupled with a finite‐volume solver for the compressible Reynolds‐averaged Navier–Stokes equations. The two‐dimensional and three‐dimensional results at Mach number Ma = 0.5 and hot gas temperature THG=540 K for different blowing ratios are compared with experimental data. Copyright © 2014 John Wiley & Sons, Ltd.

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