Measuring the Concentration of Freestream Species on a Hypersonic Transpiration-Cooled Stagnation Point

Rocher, Marc Ewenz; Hermann, Tobias; McGilvray, Matthew; Grossman, Madeleine; Vandeperre, Luc

doi:10.2514/1.a35283

Cited by 3 publications

(2 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This diffusion is strongly dependent on the material microstructure. By not accounting for the adverse pressure gradient, the model will overpredict oxidation for the blowing cases [11]. It thus provides a conservative estimate of the oxidation protection provided by mass injection.…”

Section: Oxidation Modelmentioning

confidence: 99%

See 1 more Smart Citation

Oxidation Response of Transpiration-Cooled ZrB2 on a Hypersonic Stagnation Point

Rocher

Hermann

McGilvray

2022

Journal of Spacecraft and Rockets

Self Cite

View full text Add to dashboard Cite

This work presents the oxidation response of a transpiration cooled hypersonic stagnation point made of porous ZrB 2 . Low order models are used to calculate the surface temperature and oxygen concentration for a given flight condition. An analytical material oxidation model computes the surface recession and oxide layer thickness. A 500 s steady state trajectory at 44 km altitude and 3.6 km/s velocity is found to lead to 2.2 mm recession of the 3 mm nose radius. A constant mass injection at a blowing parameter of 0.6 reduces the recession to just 0.21 mm. The displacement of freestream oxygen by transpiration cooling has a significant effect on oxidation. Not accounting for the displacement of oxygen at the surface would increase the recession by up to 197%. The recession along the transient trajectory of an envisioned

show abstract

Section: Oxidation Modelmentioning

confidence: 99%

“…Upon exiting, the coolant forms a protective film that reduces part of the aerothermal heating [9] and catalytic heating [10]. Additionally, the film reduces the mole fraction of freestream oxygen at the surface [11].…”

Section: Introductionmentioning

confidence: 99%

Oxidation Response of Transpiration-Cooled ZrB2 on a Hypersonic Stagnation Point

Rocher

Hermann

McGilvray

2022

Journal of Spacecraft and Rockets

Self Cite

View full text Add to dashboard Cite

show abstract

Heat Transfer Measurements of a Transpiration-Cooled Stagnation Point in Transient Hypersonic Flow

Naved¹,

Hermann²,

McGilvray³

et al. 2023

Journal of Thermophysics and Heat Transfer

Self Cite

View full text Add to dashboard Cite

This paper presents a novelexperimental technique where infra-red thermography is employed to directly measure the surface heat transfer of a transpiration cooled porous material in transient hypersonic flow. Experiments were conducted in the Oxford High Density Tunnel on a flat faced hemispherical probe at a single Mach 7 free-stream condition (𝑅𝑒 𝑢 = 3.84•10 6 1/m) with Nitrogen, Air, Argon, Krypton and Helium injection gases and mass flow rates ranging from 0.01-0.235 kg s −1 m −2 . Surface heat transfer measurements were extracted by imaging directly on the porous material using a FLIR A6751 high-speed long-wave infra-red camera. Porous alumina was chosen due to its favourable thermal properties for infra-red analysis and its very small pore sizes (≈ 2 𝜇m) enabling a uniform outflow. It was found that the Stanton number reduction matched to within 10% of both CFD results and correlations. Nomenclature 𝐵 ℎ Blowing parameter 𝑐 𝑝 Specific heat capacity, J kg −1 K −1 CFD Computational fluid dynamics 𝐼 Radiant intensity, W m −2 sr −1 GIS Gas injection system 𝐻 Enthalpy, J ℎ Planck's constant, m 2 kg s −1

show abstract

Numerical Simulation of Transpiration Cooling on Stagnation Line in Thermochemical Non-Equilibrium

Brody,

Lau,

Clarke

et al. 2024

AIAA SCITECH 2024 Forum

View full text Add to dashboard Cite

Sharp leading edges offer drag and maneuverability advantages for hypersonic applications such as powered flight and some gliding trajectories. The reduction in standoff distance resulting from the adoption of sharp edges, however, results in increased surface convective heating that needs to be managed. Ablative layers are unfeasible as a cooling strategy for sharp edges, because they lead to a change in surface curvature radius and render systems non-reusable. Among possible strategies, transpiration cooling has been presented as an attractive option in terms of cooling effectiveness and system complexity. In this study, a method is presented for the numerical simulation of transpiration cooling in proximity of the stagnation point of sharp leading edges or tips. The method is suited to both equilibrium and non-equilibrium flight regimes and is based on stagnation line theory presented by Cheng. Transport properties are determined through rigorous Chapman-Enskog theory. Non-equilibrium cases are handled with Park's two temperature model. The solver explicitly represents coolant flow through a porous medium. Detailed temperature profiles and mole fractions in the shock layer and within the porous medium can be evaluated, with variations in in these profiles computed as functions of flight altitude, speed, leading edge radius, and coolant flow rate and composition. Argon, helium, and nitrogen are tested for their efficacy. The ability of different coolant mixtures to limit the transport of catalytic species to the surface is studied.

show abstract

Measuring the Concentration of Freestream Species on a Hypersonic Transpiration-Cooled Stagnation Point

Cited by 3 publications

References 16 publications

Oxidation Response of Transpiration-Cooled ZrB2 on a Hypersonic Stagnation Point

Oxidation Response of Transpiration-Cooled ZrB2 on a Hypersonic Stagnation Point

Heat Transfer Measurements of a Transpiration-Cooled Stagnation Point in Transient Hypersonic Flow

Numerical Simulation of Transpiration Cooling on Stagnation Line in Thermochemical Non-Equilibrium

Contact Info

Product

Resources

About