Transpiration Cooling at Hypersonic Flight - AKTiV on SHEFEX II

Böhrk, Hannah

doi:10.2514/6.2014-2676

Cited by 22 publications

(14 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As an approach, the velocity of the film is set to u F 0.1 × u ∞ , and the temperature of the film outside the boundary layer is determined, for example, by calculating the heat exchange during transpiration. A sensitivity study concerning this value was carried out in [19].…”

Section: B Surface Blockingmentioning

confidence: 99%

Transpiration-Cooled Hypersonic Flight Experiment: Setup, Flight Measurement, and Reconstruction

Böhrk

2015

Journal of Spacecraft and Rockets

View full text Add to dashboard Cite

The present paper presents the in-flight measurement of the transpiration cooling experiment Aktive Kühlung durch Transpiration im Versuch (often referred to as AKTiV) flown on the suborbital reentry configuration Sharp Edge Flight Experiment II (often referred to as SHEFEX II). Thermal response of the structure is measured just upand downstream of a cooled sample with a noncooled reference setup on the opposite side of the vehicle. The measurement shows that the heat flux is reduced upon coolant exhaust. The maximum temperature reduction with 87 K is observed on the porous sample, while downstream the sample, the temperature is reduced by 75 K by film cooling. This corresponds to cooling efficiencies of 58 and 42% on the sample and downstream, respectively. The evaluation is supported by the semi-analytical tool HEATS, based on a transient heat balance at the surface. Comparison of the results with HEATS shows that the heat flux predicted with HEATS is in good concurrence with the measured temperatures on the cooled sample, as well as upstream and downstream with a maximum deviation by 14%. The analysis suggests that the flow condition around the sharp-edged, faceted vehicle remained laminar longer than expected. Nomenclaturem M = Mach number, -_ m = mass flow rate, kg∕s Nu = Nusselt number, -Pr = Prandtl number p = pressure, Pa R = gas constant, J∕kg · K Re = Reynolds number, -r = recovery factor, -_ q = heat flux, W∕m 2 St = Stanton number, -T = temperature, K t = time, s u = velocity, m∕s α A = heat transfer coefficient, W∕m 2 · K α V = heat transfer coefficient, W∕m 3 · K ϵ = emissivity, -η = cooling efficiency, -κ = isentropic coefficient, -λ = thermal conductivity, W∕m · K μ = dynamic viscosity, Pa · s ρ = density, kg∕m 3 σ = Stefan-Boltzmann constant, W∕m 2 · K 4 ϕ = porosity, -Subscripts C = at panel C c = coolant cond = heat conduction conv = heat convection F = film HG = hot gas p = at constant pressure r = recovery rad = radiation res = reservoir S = surface x, y = coordinates W = wall 0 = plenum ∞ = ambient

show abstract

Section: B Surface Blockingmentioning

confidence: 99%

Transpiration-Cooled Hypersonic Flight Experiment: Setup, Flight Measurement, and Reconstruction

Böhrk

2015

Journal of Spacecraft and Rockets

View full text Add to dashboard Cite

show abstract

“…There has been increasing interest in applying the transpiration cooling to more challenging conditions of high speed flow among many researchers, and they have been successful in showing the effectiveness of the technique experimentally both with and without phase change involved [25][26][27][28][29]. The flow conditions and geometries involved vary widely, and the research involves mostly experimental work.…”

Section: Numerical Simulation Of Transpiration Cooling For Re-entry Ementioning

confidence: 99%

Modelling and Simulation of Transpiration Cooling Systems for Atmospheric Re-Entry

Bandivadekar

Minisci

2020

Aerospace

View full text Add to dashboard Cite

Aerothermodynamic heating is one of the primary challenges faced in progressing towards reliable hypersonic transportation. In the present study, the transpiration cooling method applied to the thermal protection system of re-entry vehicles is investigated. The complexity in analysing the incoming heat flux for re-entry lies not only in the extreme conditions of the flow but also in the fact that the coolant flow through the porous medium needs to be treated appropriately. While the re-entering spacecraft passes through various flow regimes, the peak conditions are faced only near continuum regime. Focusing on these conditions, traditional computational fluid dynamics techniques are used to model transpiration cooling for re-entry vehicles. In the current work, the open source CFD framework OpenFOAM is used to couple two different solvers iteratively and then analyse the thermal response for flow speed conditions typical of re-entry vehicles. Independent computations are performed using the explicit, loosely coupled procedure for high speed argon flow over a 2D axi-symmetrical cylindrical vehicle. The results presented indicate distinct heat flux drop along the surface of the cylindrical vehicle as a function of parameters such as coolant pressure and wall temperature.

show abstract

“…Cooling is achieved by both convection energy within the wall while the coolant passes through the porous medium as well as a coolant film that insulates the wall from the hot gas flow [3]. Some applications nowadays considered for transpiration cooling include scramjet combustion chambers [4], rocket thrust chambers [5], turbine blades [6] and others [1,7]. Even so it has been invented in the 1950's [8], due to both advances made in manufacturing and the need for greater cooling efficiency, recently transpiration cooling has come back into the focus of research and has been intensively studied experimentally, analytically and numerically [5,9,10,11,12,13,14].…”

Section: Introductionmentioning

confidence: 99%

Probabilistic Constrained Bayesion Inversion for Transpiration Cooling

Steins¹,

Bui-Thanh²,

Herty³

et al. 2022

Preprint

View full text Add to dashboard Cite

To enable safe operations in applications such as rocket combustion chambers, the materials require cooling to avoid material damage. Here, transpiration cooling is a promising cooling technique. Numerous studies investigate possibilities to simulate and evaluate the complex cooling mechanism. One naturally arising question is the amount of coolant required to ensure a safe operation. To study this, we introduce an approach that determines the posterior probability distribution of the Reynolds number using an inverse problem and constraining the maximum temperature of the system under parameter uncertainties. Mathematically, this chance inequality constraint is dealt with by a generalized Polynomial Chaos expansion of the system. The posterior distribution will be evaluated by different Markov Chain Monte Carlo based methods. A novel method for the constrained case is proposed and tested among others on two-dimensional transpiration cooling models.

show abstract

Transpiration Cooling at Hypersonic Flight - AKTiV on SHEFEX II

Cited by 22 publications

References 15 publications

Transpiration-Cooled Hypersonic Flight Experiment: Setup, Flight Measurement, and Reconstruction

Transpiration-Cooled Hypersonic Flight Experiment: Setup, Flight Measurement, and Reconstruction

Modelling and Simulation of Transpiration Cooling Systems for Atmospheric Re-Entry

Probabilistic Constrained Bayesion Inversion for Transpiration Cooling

Contact Info

Product

Resources

About