Navier-Stokes Simulations of Hypersonic Flows with Coupled Graphite Ablation

Bianchi, Daniele; Nasuti, Francesco; Martelli, Emanuele

doi:10.2514/1.47995

Cited by 65 publications

(29 citation statements)

References 16 publications

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“…Preliminary simulations were carried out for case 1 with fast acoustic waves, over a small domain (grid size 360 × 150) with streamwise length equal to 10 nose radii, and geometry presented in figure 1, in order to check the linearity of the pressure response along the wall, with disturbance amplitudes ranging from 10 −1 to 10 −4 . As shown in figure 1, the computational domain is made in such a way to be well adapted to both the body and the shock shape, based on the grid generation method by Bianchi et al [22]. The imposed single frequency in the preliminary simulations is high enough to provide a wavelength comparable with the size of the domain.…”

Section: Flow Conditions For the Six Cases And Preliminary Resultsmentioning

confidence: 99%

Acoustic Leading-Edge Receptivity for Supersonic/Hypersonic Flows over a Blunt Wedge

Cerminara

Sandham

2017

AIAA Journal

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Section: Flow Conditions For the Six Cases And Preliminary Resultsmentioning

confidence: 99%

Acoustic Leading-Edge Receptivity for Supersonic/Hypersonic Flows over a Blunt Wedge

Cerminara

Sandham

2017

AIAA Journal

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“…To obtain a better evaluation of the ablating flowfield, the mass and energy exchange mechanisms must be carefully modeled using the information from the Navier-Stokes solver; this has been performed integrating the numerical solver with a computational surface thermochemistry technique. 11,14,15 …”

Section: Theoretical Modelingmentioning

confidence: 98%

“…The first approach has been extensively described in Ref. [11] and is based on the hypothesis that local chemical equilibrium is established at the solid-gas interface and hence the erosion process is assumed to be diffusion-limited. The finite-rate model described herein is more general and includes the diffusion-limited condition.…”

Section: Iic2 Heterogeneous Reaction Kineticsmentioning

confidence: 99%

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Aerothermodynamic Analysis of Reentry Flows with Coupled Ablation

Bianchi¹,

Nasuti

Onofri

2011

17th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

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A study of graphite ablation in reentry flows is carried out by a fully-coupled surface ablation approach integrated with a two-dimensional axisymmetric Navier-Stokes solver. The gas-surface interaction model is based on both chemical equilibrium and finite-rate ablation modeling and can account for both surface oxidation and sublimation. The surface temperature is obtained from the steady-state ablation approximation. This numerical procedure can predict aerothermal heating, chemical species concentrations, and carbon material ablation rate over the heat-shield surface of reentry vehicles. Two dimensional axi-symmetric simulations have been performed to numerically reproduce the ablation of a graphite sphere-cone for which literature data are available from testing performed in the Interaction Heating Facility at the NASA Ames Research Center. The freestream conditions of the selected test case are typical for Earth reentry from a planetary mission. The predicted ablation rate and surface temperature assuming frozen chemistry in the flow show a good agreement with the available experimental data. The agreement is further improved by the use of finite-rate ablation modeling. Nomenclature A = cross section area, m 2 D im = effective diffusion coefficient, m 2 /s h = enthalpy, J/kg j = diffusional mass flux, kg/m 2 · s k = thermal conductivity, W/m · K m = mass blowing rate per unit area, kg/m 2 · s N c = number of species p = pressure, N/m 2 q = heat flux per unit area, W/m 2 r = distance from surface, ṁ s = recession rate, m/s T = temperature, K t = time, s u = streamwise velocity, m/s v = mass motion of the mixture, m/s v = velocity component normal to surface, m/s W = molecular weight, kg/kmole y = species mass fractionSubscripts i = species s = solid (graphite) properties at gas/solid interface s i = solid (graphite) properties at initial conditions w = gas properties at gas/solid interface Symbols ∆H abl = heat of ablation, J/kg ǫ = surface emissivity η = outward coordinate normal to surface µ = viscosity, kg/m · s ρ = density, kg/m 3 σ = Stefan-Boltzmann constanṫ ω = species source term, kg/m 2 · s

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“…The purpose of the present study is to extend a CFD approach validated for the study of carbonbased pyrolyzing and non-pyrolyzing materials [8][9][10][11][12][13] to the case of silica-based materials and to perform a comprehensive analysis of TPS materials behavior in oxygen/methane thruster environment. After the description of the theoretical and numerical models, the first part of the analysis is dedicated to the validation, by means of comparison with experimental data, of the newly developed boundary condition and gassurface interaction model for silica-based materials.…”

Section: Introductionmentioning

confidence: 99%

Ablative Material Behavior in Oxygen/Methane Thruster Environment

Turchi

Bianchi

Nasuti

et al. 2012

43rd AIAA Thermophysics Conference

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Ablative materials represent a low cost and reliable means to insulate rocket engine components from high-temperature, corrosive combustion product environments. Besides their diffuse application in solid rocket nozzles, their use also emerges as a valid alternative in liquid rocket engines. Together with the growing interest in oxygen/methane liquid rocket engines, these materials have gained attention as possible insulator for small upperstage engines or in-space thrusters. In this framework, a validated approach for the study of carbon-based pyrolyzing and non-pyrolyzing materials, together with a novel boundary condition developed to analyze the silica-based material behavior, has been used to numerically reproduce the material response in the highly oxidizing environment generated by the combustion of oxygen and methane. At first, the validation against experimental data of the silica-based material erosion model is presented. Subsequently, the behavior and the response of different ablators in a oxygen/methane environment is numerically investigated for a wide range of operating conditions. Commonly made assumptions in the simulation of the material response are thoroughly analyzed and a critical overview of the results is presented. Nomenclaturebinary diffusion coefficient, m 2 /s h = enthalpy, J/kg k = thermal conductivity, W/m · K N c = number of specieṡ m = mass blowing rate per unit area, kg/m 2 · s p = pressure, N/m 2 q radout = wall radiative heat flux, W/m 2 s = erosion rate, m/s T = temperature, K t = time, s v = flow velocity, m/s v = velocity component normal to surface, m/s * Ph.D. Student, Dipartimento di Ingegneria Meccanica e Aerospaziale, Via Eudossiana 18. AIAA Student Member. alessandro.turchi@uniroma1.it. ẇ i = species source term in control volume, kg/m 3 · s x = mole fraction y = mass fraction y + = dimensionless wall distance Subscripts c = charred state f = failed material g = pyrolysis gas i = species s = solid state v = virgin state w = gas properties at gas/solid interface Symbols η = outward coordinate normal to surface Γ m = mass resin fraction Γ V = volume resin fraction µ = viscosity, kg/m · s µ t = turbulent viscosity, kg/m · s ρ = density, kg/m 3 ρ A = primary resin component density, kg/m 3 ρ B = secondary resin component density, kg/m 3 ρ R = reinforcing material density, kg/m 3

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Navier-Stokes Simulations of Hypersonic Flows with Coupled Graphite Ablation

Cited by 65 publications

References 16 publications

Acoustic Leading-Edge Receptivity for Supersonic/Hypersonic Flows over a Blunt Wedge

Acoustic Leading-Edge Receptivity for Supersonic/Hypersonic Flows over a Blunt Wedge

Aerothermodynamic Analysis of Reentry Flows with Coupled Ablation

Ablative Material Behavior in Oxygen/Methane Thruster Environment

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