Validation Process for Blowing and Transpiration-Cooling in DPLR

Martinelli, Scott K.; Ruffin, Stephen M.; McDaniel, Ryan; Brown, James L.; Wright, Michael J.; Hash, David

doi:10.2514/6.2007-4255

Cited by 19 publications

(15 citation statements)

References 6 publications

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“…However, considerable effort has been devoted in recent years towards the eventual development of a coupled prediction capability by implementing surface mass transfer boundary conditions into computational fluid dynamics (CFD) solvers. 9,10 The effects of surface blowing on boundary layer instability at supersonic Mach numbers have also been studied recently in the context of a self-similar a) Electronic mail: fei.li@nasa.gov…”

Section: Introductionmentioning

confidence: 99%

Effects of injection on the instability of boundary layers over hypersonic configurations

Choudhari

Chang

et al. 2013

Physics of Fluids

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A high-order numerical method to study hypersonic boundary-layer instability including high-temperature gas effects Phys. Fluids 23, 084108 (2011); 10.1063/1.3614526Direct numerical simulation of breakdown to turbulence in a Mach 6 boundary layer over a porous surface Phys. Fluids 22, 094105 (2010);Computations are performed to study the boundary layer instability mechanisms pertaining to hypersonic vehicles with significant ablative effects. The process of laminar-turbulent transition over vehicles with ablative heat shields can be influenced by both the out-gassing associated with surface pyrolysis and the resulting modification of surface geometry including the formation of micro-roughness. To isolate the effects of out-gassing, this paper examines the stability of canonical boundary layer flows over smooth surfaces in the presence of gas injection into the boundary layer, with an emphasis on the case of massive injection that is relevant to previous laboratory experiments. For a slender cone, the effects of strong out-gassing on the predominantly second mode instability are found to be weakly stabilizing. This new, somewhat surprising result is confirmed by computations carried out on a flat plate boundary layer at high Mach numbers. In contrast, for a blunt capsule flow dominated by first mode instability, the effect of out-gassing is shown to be strongly destabilizing, consistent with the well-known behavior of subsonic boundary layers. C 2013 AIP Publishing LLC. [http://dx.

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Section: Introductionmentioning

confidence: 99%

Effects of injection on the instability of boundary layers over hypersonic configurations

Choudhari

Chang

et al. 2013

Physics of Fluids

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“…This blowing boundary condition has been tested over a wide range of blowing rates, assuring the robustness of the implementation. Following the same methodology for the verification and validation of NASA Ames's DPLR code [36] and [37], the blowing boundary of LeMANS has also been verified and validated [7,38]. More details on these relations are provided in Ref.…”

Section: Lemans: Unstructured Three-dimensional Navier-stokes Somentioning

confidence: 99%

Modeling of Heat Transfer Attenuation by Ablative Gases During the Stardust Reentry

Martin

Boyd

2015

Journal of Thermophysics and Heat Transfer

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Modern space vehicles designed for planetary exploration use ablative materials to protect the payload against the high heating environment experienced during reentry. To properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. The present study aims to examine the effects of the blowing of ablation gas in the outer flow field. Using six points on the Stardust entry trajectory at the beginning of the continuum regime, from 81 to 69 km, the various components of the heat flux are compared to air-only solutions. Although an additional component of the heat flux is introduced by mass diffusion, this additional term is mainly balanced by the fact that the translational-rotational component of the heat flux, the main contributor, is greatly reduced. Although a displacement of the shock is observed, it is believed that the most prominent effects are caused by a modification of the chemical composition of the boundary layer, which reduces the gas-phase thermal conductivity. NomenclatureB 0 = nondimensional ablation rate C = vector of source terms D = mass diffusion coefficient, m 2 ∕s E = energy, J∕m 3 e = energy, J∕kg F = inviscid flux matrix F d = diffusive flux matrix h = species enthalpy vector, J∕kg I = identity matrix J = directional species diffusion, kg∕m 2 · s Kn = Knudsen number k = thermal conductivity, W∕m · K _ m 0 0 = mass flow rate, kg∕m 2 · s p = pressure, Pa Q = vector of conserved variables q = heat flux, W∕m 2 T = temperature, K U, v = velocity, m∕s _ w = mass source term, kg∕m 3 · s _ w v = vibrational energy relaxation source term, J∕m 3 · s Y = mass fraction, kg∕kg η = distance normal to the wall, m ρ = mass density, kg∕m 3 τ = viscous tensor, Pa Subscripts c = char g = gas blown nc = next to the wall s = species t = time tr = translational-rotational ve = vibrational-electron-electronic w = wall ∞ = freestream

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“…This blowing boundary condition has been tested over a wide range of blowing rates, assuring the robustness of the implementation. Following the methodology for the verification and validations of NASA Ames' DPLR code 21 and NASA Langley's LAURA code, 20 the blowing boundary of LeMANS has also been verified and validated. 5,6…”

Section: Iva Blowing Boundary Conditionsmentioning

confidence: 99%

Mesh Tailoring for Strongly Coupled Computation of Ablative Material in Nonequilibrium Hypersonic Flow

Martin

Boyd

2010

10th AIAA/ASME Joint Thermophysics and Heat Transfer Conference

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A one-dimensional material response implicit solver with surface ablation and pyrolysis is strongly coupled to LeMANS, a CFD code for the simulation of weakly ionized hypersonic flows in thermo-chemical non-equilibrium. Using blowing wall boundary conditions and a moving mesh algorithm, the results of a strongly coupled solution of a sample re-entry problem are presented. Because of the requirement of a coupling scheme, an Arbitrary Lagrangian-Eulerian (ALE) approach is used to compute the flux, allowing the mesh to move as the surface ablates. However, as the shape of the vehicle changes, the shock location and geometry are also modified. Using the moving mesh capabilities of the flow solver, a mesh tailoring algorithm is presented, and results obtained with this new functionality are compared to un-tailored mesh results.

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Validation Process for Blowing and Transpiration-Cooling in DPLR

Cited by 19 publications

References 6 publications

Effects of injection on the instability of boundary layers over hypersonic configurations

Effects of injection on the instability of boundary layers over hypersonic configurations

Modeling of Heat Transfer Attenuation by Ablative Gases During the Stardust Reentry

Mesh Tailoring for Strongly Coupled Computation of Ablative Material in Nonequilibrium Hypersonic Flow

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