Ablation of Carbonaceous Materials in a Hydrogen-Helium Arcjet Flow

Park, Chul; Lundell, J. H.; Green, M. J.; Winovich, W.; Covington, Michael A.

doi:10.2514/3.48589

Cited by 27 publications

(5 citation statements)

References 6 publications

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“…For Galileo e.g. conditions at heat flux levels around 200 MW/m 2 at impact pressures of 0.3 MPa were achieved [20]. Unfortunately, this facility was dismounted.…”

Section: With V•dv•sin( )/Dy = -Dv/dt Assuming H >> H Ref and Integrmentioning

confidence: 99%

Experimental Simulation of High Enthalpy Planetary Entries

Herdrich¹,

Fertig²,

Löhle³

2009

TOPPJ

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For the current exploration programs high enthalpy landing missions are foreseen. It is rather difficult to simulate the corresponding enthalpies with steady state facilities. For the case of sample return missions such as Genesis, STARDUST or Hayabusa hyperbolic entries require maximum enthalpies of about 80 MJ/kg. Atmospheric entry parameters of relevance were derived with the model of Allan and Eggers which was developed for ballistic capsules. The model was then extended by validated engineering equations for both convective and radiation heat flux. In addition, the integral for the total convective heat load and the upper Gamma function integrals for the integral radiation heat load were derived and solved. This provides the potential to assess parameters relevant within the test philosophy such as e.g. the test duration while having a material sample exposed e.g. under maximum heat flux conditions to the plasma. In this context it is shown that the high specific enthalpies can be reproduced using e.g. magnetoplasmadynamically driven plasma wind tunnels. Atmospheric entry missions at the planets, however, are accompanied by initial kinetic energies for the spacecraft that are at least in the order of half of the second power of the first cosmic velocity of the related planet. Corresponding specific enthalpies e.g. for the Jovian entry are by a factor of almost 8 higher than the enthalpies experienced within a hyperbolic Earth entry. The paper discusses potential facilities that can be used for the investigation of these entry missions.

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“…For Galileo e.g. conditions at heat flux levels around 200 MW/m 2 at impact pressures of 0.3 MPa were achieved [20]. Unfortunately, this facility was dismounted.…”

Section: With V•dv•sin( )/Dy = -Dv/dt Assuming H >> H Ref and Integrmentioning

confidence: 99%

Experimental Simulation of High Enthalpy Planetary Entries

Herdrich¹,

Fertig²,

Löhle³

2009

TOPPJ

View full text Add to dashboard Cite

show abstract

“…Alternative methods have been employed such as directing acetylene torches [7], rocket exhaust streams and other high temperature gas jets in an attempt to reproduce re-entry conditions [8]. Plasma arc jets have been used extensively for testing TPSs in ionising environments at very high temperatures and pressures [9]. These arc jets consist of an intensely heated gas or gas mixture being expanded through a convergent-divergent nozzle into a vacuum chamber with the test material located in the path of the plasma jet.…”

Section: Graphical Abstract Introductionmentioning

confidence: 99%

Simulating the complete pyrolysis and charring process of phenol–formaldehyde resins using reactive molecular dynamics

et al. 2022

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We examine the mechanism of pyrolysis and charring of large (> 10,000 atom) phenol–formaldehyde resin structures produced using pseudo-reaction curing techniques with formaldehyde/phenol ratios of 1.0, 1.5 and 2.0. We utilise Reactive Molecular Dynamics (RMD) with a hydrocarbon oxidation parameter set to simulate the high-temperature thermal decomposition of these resins at 1500, 2500 and 3500 K. Our results demonstrate that the periodic removal of volatile pyrolysis gasses from the simulation box allows us to achieve near complete carbonisation after only 2 ns of simulation time. The RMD simulations show that ring openings play a significantly larger role in thermal decomposition than has previously been reported. We also identify the major phases of phenolic pyrolysis and elucidate some of the possible mechanisms of fragment formation and graphitisation from the RMD trajectories and compute the thermal and mechanical properties of the final pyrolysed structures. Graphical abstract

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“…Historically, the majority of gas giant entry research was either performed for the design of the Galileo probe, [1][2][3][4] or to analyse issues associated with it 5,6 after it flew and the heat shield recession was different to what had been expected. 7 Recently, there has been renewed interest in future gas giant entry probe missions.…”

Section: Introductionmentioning

confidence: 99%

Generating High Speed Earth Re-entry Test Conditions in an Expansion Tube for Interplanetary Return Missions

James¹,

Lewis²,

Gildfind³

et al. 2019

Proceedings of the 32nd International Symposium on Shock Waves (ISSW32 2019)

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In 2010, planetary entry probe missions to Uranus and Saturn were proposed. This paper details an investigation exploring the operating limits of the X2 superorbital expansion tube at the University of Queensland for the simulation of test conditions related to these proposed entries. Theoretical calculations showed that X2 could recreate the stagnation enthalpy of the proposed 22.3 km/s Uranus entry but not the stagnation enthalpy of the proposed 26.9 km/s Saturn entry. Experiments were able to confirm the theoretical performance calculations. However, losses caused some of the experimental shock speeds to be up to 10% slower than predicted, and due to the high velocity nature of the experiments, the shock speed errors were large making it difficult to properly quantify the test conditions. Further theoretical analysis investigated the possibility of using a more powerful free piston driver to simulate the Saturn entry conditions, and the analysis showed that with a slightly more powerful driver than X2's current most powerful configuration, the stagnation enthalpy of the proposed Saturn entry or other slightly faster entries proposed in the literature could be simulated. However, a very powerful driver would be required to recreate the stagnation enthalpies of these entries with the excess enthalpy needed to perform binary scaled experiments for an X2 sized facility.

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Ablation of Carbonaceous Materials in a Hydrogen-Helium Arcjet Flow

Cited by 27 publications

References 6 publications

Experimental Simulation of High Enthalpy Planetary Entries

Experimental Simulation of High Enthalpy Planetary Entries

Simulating the complete pyrolysis and charring process of phenol–formaldehyde resins using reactive molecular dynamics

Generating High Speed Earth Re-entry Test Conditions in an Expansion Tube for Interplanetary Return Missions

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