Preliminary Design of Super-Orbital Earth Entry Flight Experiment Using VOLNA Launcher

Na, J.J.; Park, C.; Baek, Seung-Wook

doi:10.2514/6.2008-1129

Cited by 3 publications

(4 citation statements)

References 8 publications

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“…The limiting criterion (i.e., how much self-absorption is required that a line peak emits according to a blackbody) is exp−n l σ λ Δz < 0.1 (13) with the absorption cross section σ λ and a characteristic length Δz [21]. The characteristic length needed to fulfill this criterion is a fraction of a millimeter for strong lines, e.g., lines of the multiplets at 149.…”

Section: Blackbody Limitmentioning

confidence: 99%

“…As the reentry speed increases, radiative heating becomes more and more dominant [10][11][12]. It has previously been found that the vacuum ultraviolet (VUV) spectral region, which is the 100-200 nm wavelength interval, contributes a major part to the total radiative heat flux [5,[13][14][15][16][17]. Ablative materials interact with the flowfield, which can have a significant effect on the radiative heat flux encountered by the vehicle.…”

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confidence: 99%

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Characterization of a Reentry Plasma Wind-Tunnel Flow with Vacuum-Ultraviolet to Near-Infrared Spectroscopy

Hermann

Löhle

Zander

et al. 2016

Journal of Thermophysics and Heat Transfer

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This paper presents the analysis of optical emission spectroscopic measurements from vacuum ultraviolet (120 nm) to near infrared (960 nm) in a high-enthalpy air plasma flow corresponding to superorbital reentry conditions. The vacuum ultraviolet measurements have been realized with a new experimental setup allowing measurements through a bore hole in the sample. Using the commonly applied optical emission spectroscopy from the side, the radiation transport along the line of sight of the vacuum ultraviolet measurements has been assessed. This allowed the determination of the local ground state densities of atomic oxygen and atomic nitrogen from a branching ratio analysis and the blackbody limiting correction of the vacuum ultraviolet radiation. Through the analysis of the absorption in the borehole, the spectra have been corrected, resulting in a stagnation point radiative heat flux in the vacuum ultraviolet of 235 kW∕m 2 .= local mass-specific enthalpy, MJ∕kg I = arc current, A K = proportionality constant for air, W∕MJ∕kg·Pa 0.5 ·m 1.5 k = Boltzmann constant, J∕K k cal = calibration factor, W∕m 2 · nm · sr∕counts∕s L λ = spectral radiance, W∕m 2 · nm · sr L λ;Limit = blackbody limit spectral radiance, W∕m 2 · nm · sr M = magnification _ m = mass flow, g∕s n = number density, m −3 n i = excited state population density, m −3 n 0 = ground state population density, m −3 P = electric power, kW P k = spectral line shape, nm −1 p = pressure, hPa _ q = heat flux, kW∕m 2 R eff = effective nose radius, mm r = radial distance, mm S = raw signal, counts/s s = distance from the probe surface, mm s 0 = distance between object and focusing element, mm= vibrational quantum number x = axial distance from the nozzle, mm y = horizontal distance from the nozzle, mm z = vertical distance from the nozzle, mm α λ = absorption coefficient, m −1 δ = full width at half-maximum of line broadening, nm ε λ = emission coefficient, W∕m 3 · nm · sr ε = spectrally integrated emission coefficient, W∕m 3 · sr λ = wavelength, nm σ λ = absorption cross section, m 2 Subscripts BB = blackbody DL = deuterium lamp exc = electronic excitation IS = integrating sphere l = lower state rot = rotational tot = total trans = translational u = upper state vib = vibrational

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Section: Blackbody Limitmentioning

confidence: 99%

mentioning

confidence: 99%

Characterization of a Reentry Plasma Wind-Tunnel Flow with Vacuum-Ultraviolet to Near-Infrared Spectroscopy

Hermann

Löhle

Zander

et al. 2016

Journal of Thermophysics and Heat Transfer

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“…However, species from the heat shield can also act as strong absorbers thus reducing the radiative heat flux. Absorbed radiation is either re-emitted or transported downstream becoming an additional convective heat flux to the wall [10]. Both increases and decreases in radiative heating through ablation have been reported in numerical analyses [6,11,12].…”

mentioning

confidence: 91%

“…Both increases and decreases in radiative heating through ablation have been reported in numerical analyses [6,11,12]. In terms of total radiative heat flux encountered by the vehicle the vacuum ultraviolet (VUV) regime, i. e. 100 nm-200 nm, is considered the main source [9,10,[13][14][15][16]. However, experimental investigations of this wavelength regime are sparse [17][18][19][20][21][22].…”

mentioning

confidence: 99%

Influence of Ablation on Vacuum-Ultraviolet Radiation in a Plasma Wind Tunnel Flow

Hermann

Löhle

Fasoulas

et al. 2017

Journal of Thermophysics and Heat Transfer

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Plasma wind tunnel experiments have been performed simulating a Hayabusa reentry trajectory point at 78.8 km altitude with a velocity of 11.7 km/s corresponding to a local mass-specific enthalpy of 68.4 MJ/kg and a stagnation pressure of 2.44 kPa. Ablation-radiation coupling is investigated using a carbon preform sample, a lightweight carbon phenolic ablator sample and cooled copper. Optical emission spectroscopic measurements in the vacuum ultraviolet (VUV) regime (116 nm-197 nm) have been conducted through a bore hole in the stagnation point of the different samples. Optical emission spectroscopic measurements in the UV/VIS spectral range (320 nm-810 nm) have been conducted viewing the plasma from the side. The stagnation point VUV radiation to the carbon preform sample is strongest while it is weakest for the carbon phenolic sample. In the UV/VIS both carbon based material sama PhD student, High Enthalpy Flow Diagnostic Group, IRS, Member AIAA

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Preliminary Design of Superorbital Earth Entry Flight Experiment Using the Volna Launcher

Park

Chang

et al. 2008

Journal of Spacecraft and Rockets

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Preliminary Design of Super-Orbital Earth Entry Flight Experiment Using VOLNA Launcher

Cited by 3 publications

References 8 publications

Characterization of a Reentry Plasma Wind-Tunnel Flow with Vacuum-Ultraviolet to Near-Infrared Spectroscopy

Characterization of a Reentry Plasma Wind-Tunnel Flow with Vacuum-Ultraviolet to Near-Infrared Spectroscopy

Influence of Ablation on Vacuum-Ultraviolet Radiation in a Plasma Wind Tunnel Flow

Preliminary Design of Superorbital Earth Entry Flight Experiment Using the Volna Launcher

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