Wall Catalytic Recombination and Boundary Conditions in Nonequilibrium Hypersonic Flows - with Applications

Scott, Clayton

doi:10.1007/978-1-4612-0369-8_6

Cited by 20 publications

(23 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…a binary interaction model with full energy accommodation, 13,14 is implemented in LeMANS. It is implemented by balancing the mass flux of the relevant species taking the consumption/production at the wall into account.…”

Section: Boundary Condition Descriptionmentioning

confidence: 99%

Computation of Surface Catalysis for Graphite Exposed to High-Enthalpy Nitrogen Flow

Anna

Boyd

2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

View full text Add to dashboard Cite

The high temperatures on a hypersonic vehicle surface caused by heat loads encountered during (re-)entry through a planetary atmosphere require a reliable Thermal Protection System (TPS) that makes a good understanding of the physical and chemical processes essential for its design. Surface catalysis is a crucial chemical process that directly impacts aerothermal heating of the vehicle TPS. To study the effects of this process, a binary catalytic atom recombination model is implemented in a computational fluid dynamics (CFD) code. The study examines the effects of surface catalysis for graphite exposed to high enthalpy nitrogen flow. As expected, surface catalysis strongly affects the boundary layer gradients of temperature and species concentration, and heat transfer to the surface. A fully catalytic surface causes the heat flux to increase by a factor of approximately 3.5. The physical accuracy of the model is assessed using data from experimental tests conducted in the Inductively Coupled Plasma (ICP) Torch Facility at the University of Vermont. Comparisons are presented of computed results with measured experimental data for translational temperature and relative nitrogen atom number density in the flow in front of the test article. NomenclatureD 12 binary diffusion coefficient between species 1 and 2 [m 2 /s] J sp species diffusion flux [kg/m 2 /s] M mass flux [kg/m 2 /s] N sp number of species in the mixture [dimensionless number] T translational-rotational temperature [K] Y mass fraction [dimensionless number] h sp species enthalpy [J/kg] k B Boltzmann constant k w wall catalytic speed [m/s] m particle mass [kg] q total heat flux [W/m 2 ] q conv convective heat flux [W/m 2 ] q dif f diffusive heat flux [W/m 2 ] γ wall catalytic efficiency [dimensionless number] κ thermal conductivity [W/m/K] ρ density [kg/m 3 ] subscripts w wall value tr translational-rotational energy mode ve vibrational-electronic energy mode ∞ reference freestream conditions sp species value * Graduate Student, Student Member AIAA. † James E. Knott Professor, Fellow AIAA.

show abstract

Section: Boundary Condition Descriptionmentioning

confidence: 99%

Computation of Surface Catalysis for Graphite Exposed to High-Enthalpy Nitrogen Flow

Anna

Boyd

2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

View full text Add to dashboard Cite

show abstract

“…23 Early analyses used a catalytic recombination speed, k w , on the order of 700 cm/sec for both oxygen and nitrogen recombination at the surface. However, later studies generated separate recombination rates for oxygen and nitrogen recombination based on experimental data.…”

Section: Catalytic Recombination Coefficientsmentioning

confidence: 99%

“…The chemical heating rate is computed from a combination of unequal thermal and multicomponent diffusion coefficients and species concentration gradients. 23 If thermal diffusion is neglected, Equation (14) can be rewritten…”

Section: A Lower Fuselage Centerline Regionmentioning

confidence: 99%

BLIMPK/Streamline Surface Catalytic Heating Predictions on the Space Shuttle Orbiter

Marichalar

Rochelle

Kirk

et al. 2006

44th AIAA Aerospace Sciences Meeting and Exhibit

View full text Add to dashboard Cite

“…The recombination rates at the wall can be derived from the normal mass flux term in the Navier-Stokes equations for a gas in chemical nonequilibrium [22]. Early analyses [8] used a catalytic recombination speed, k w , on the order of 700 cm=s for both oxygen and nitrogen recombination at the surface.…”

Section: Catalytic Recombination Coefficientsmentioning

confidence: 99%

“…The conductive heating rate is the product of the thermal conductivity of the material and the temperature gradient at the surface. The chemical heating rate is computed from a combination of unequal thermal and multicomponent diffusion coefficients and species concentration gradients [22]. If thermal diffusion is neglected, Eq.…”

Section: B Nose Cap/chin Panel Regionmentioning

confidence: 99%

Boundary Layer/Streamline Surface Catalytic Heating Predictions on Space Shuttle Orbiter

Marichalar¹,

Rochelle²,

Kirk³

et al. 2006

Journal of Spacecraft and Rockets

View full text Add to dashboard Cite

This paper describes the analysis of localized catalytic heating effects to the U.S. Space Shuttle Orbiter thermal protection system. The analysis applies to the high-temperature reusable surface insulation on the lower fuselage and wing acreage, as well as the reinforced carbon-carbon on the nose cap, chin panel, and wing leading edge. The objective was to use a modified two-layer approach to predict the catalytic heating effects on the Orbiter windward thermal protection system assuming localized highly catalytic or fully catalytic surfaces. The method incorporated the boundary layer integral matrix procedure-kinetic code with streamline inputs from viscous Navier-Stokes solutions to produce heating rates for localized fully catalytic and highly catalytic surfaces as well as for nominal partially catalytic surfaces (either reinforced carbon-carbon or reaction cured glass) with temperature-dependent recombination coefficients. The highly catalytic heating results showed very good correlation with Orbiter experiments STS-2, -3, and -5 centerline and STS-5 wing flight data. Recommended catalytic heating factors were generated for use in future shuttle missions to perform quick-time atmospheric reentry analysis of damaged or repaired thermal protection system areas. The catalytic factors are presented along streamlines and as a function of stagnation enthalpy for use with arbitrary shuttle trajectories. Nomenclature b= bump factor equal to ratio of local catalytic to nominal heating rate C i = mass fraction of ith species D ij = multicomponent diffusion coefficient ê ;ê ;ê = streamline coordinate-aligned unit vectors H cl = arcjet nozzle centerline enthalpy, J=kg H w = wall enthalpy, J=kg h 0 = enthalpy of formation, J=kg h arc = heating parameter î;ĵ;k = Cartesian-aligned unit vectors L = Orbiter reference length, m M i = normal mass flux of ith species, kg=m 2 s P meas = measured test article surface pressure, N=m 2 q = heat flux per unit area, W=m 2 r = position vector, m T = temperature, K t = time, s u; v; w = Cartesian velocity components, m=s V = velocity vector, m=s Xo; Yo; Zo = axial, lateral, and vertical shuttle coordinates, m x = Orbiter axial distance from apex, m x; y; z = Orbiter Cartesian axis system, m = chemical energy accommodation coefficient = catalytic recombination rate coefficient = emissivity = thermal conductivity, W=m 2 K ; ; = streamline coordinate system = density, kg=m 3 = Stefan-Boltzmann constant (5:67 10 8 W=m 2 K 4 )

show abstract

Wall Catalytic Recombination and Boundary Conditions in Nonequilibrium Hypersonic Flows - with Applications

Cited by 20 publications

References 55 publications

Computation of Surface Catalysis for Graphite Exposed to High-Enthalpy Nitrogen Flow

Computation of Surface Catalysis for Graphite Exposed to High-Enthalpy Nitrogen Flow

BLIMPK/Streamline Surface Catalytic Heating Predictions on the Space Shuttle Orbiter

Boundary Layer/Streamline Surface Catalytic Heating Predictions on Space Shuttle Orbiter

Contact Info

Product

Resources

About