Investigation of Pyrolysis Gas Chemistry in an Inductively Coupled Plasma Facility

Tillson, Corey

doi:10.2514/6.2016-3235

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…In order to increase plasma conductivity and eliminate material surface evolution due to nitridation and oxidation and, thereby, improve ETC performance, argon gas is used as the working fluid. As such, the temperature of the plasma is taken from line-of-sight intensity calibrated emission measurements that are subsequently Abel-inverted to access spatially resolved profiles [29]. Torch and chamber conditions considered in this study are shown in Table 1.…”

Section: Plasma Torch Experimentsmentioning

confidence: 99%

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Evaluation of Computational Models for Electron Transpiration Cooling

et al. 2021

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Recent developments in the world of hypersonic flight have brought increased attention to the thermal response of materials exposed to high-enthalpy gases. One promising concept is electron transpiration cooling (ETC) that provides the prospect of a passive heat removal mechanism, rivaling and possibly outperforming that of radiative cooling. In this work, non-equilibrium CFD simulations are performed to evaluate the possible roles of this cooling mode under high-enthalpy conditions obtainable in plasma torch ground-test facilities capable of long flow times. The work focuses on the test case of argon gas being heated to achieve enthalpies equivalent to post-shock conditions experienced by a vehicle flying through the atmosphere at hypersonic speed. Simulations are performed at a range of conditions and are used to calibrate direct comparisons between torch operating conditions and resulting flow properties. These comparisons highlight important modeling considerations for simulating long-duration, hot chamber tests. Simulation results correspond well with the experimental measurements of gas temperature, material surface temperature as well as measured current generated in the test article. Theoretical methods taking into consideration space charge limitations are presented and applied to provide design suggestions to boost the ETC effect in future experiments.

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Section: Plasma Torch Experimentsmentioning

confidence: 99%

“…For future tests using the same torch settings as the results presented in this work, design points for ideal ETC performance can be estimated using Equations ( 28) and (29). Figure 13 shows the wall temperature distribution for the case 3 and 4 inlet conditions, under a range of surface emissivity values.…”

Section: Considerations For Future Experimentsmentioning

confidence: 99%

Evaluation of Computational Models for Electron Transpiration Cooling

et al. 2021

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“…In this configuration the image height h that is imaged onto 256 vertical pixels of the CCD is 9.4 mm. 4 The optical arraignment, including the collection beam path, and the vertical collection region can be seen below in Fig. 6.…”

Section: B Instrumentationmentioning

confidence: 99%

“…Investigation of pyrolysis gases has been undertaken in an extension of earlier work. 4 This investigation focuses on the interactions of PICA pyrolysis gases with different plasmas using emission spectroscopy to measure the characteristics of the pyrolysis chemistry. To better understand the interactions between the pyrolysis gases and plasma, a gas injection probe has been designed for use in the UVM 30 kW Inductively Coupled Plasma (ICP) Torch.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Pyrolyzing Ablators Using a Gas Injection Probe

Martin

Meyers

Fletcher

et al. 2017

55th AIAA Aerospace Sciences Meeting

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The pyrolysis mechanism of Phenolic Impregnated Carbon Ablator (PICA) makes it a viable candidate for thermal protection systems for spacecraft atmospheric entry. However, a better understanding of the pyrolysis mechanism and of the interaction of the pyrolysis gases with the plasma flow is needed to improve heat-shield designs. The present study extends previous work in the design, development, and testing of a gas-injection probe to simulate pyrolysis in the UVM 30kW Inductively Coupled Plasma (ICP) Torch Facility. A parallel effort in Computational Fluid Dynamics (CFD) modeling of the injection probe during plasma testing is also discussed. Measurements were obtained with the injection probe in the facility in an argon buffered nitrogen condition with carbon dioxide being injected into the flow through a FiberForm plug. Spatially resolved high-resolution emission data were acquired during this test. Spectral signatures of CN, OH, and NH bands were detected and their spatial locations determined using a spectrometer equipped with a CCD camera at the exit plane. At the same time the relative conditions in the facility were used to create a CFD model of the experiment. Comparisons between the measured, spatially resolved, emission spectra and the simulations calculated using a radiative transport model from the CFD results show reasonable agreement.

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