Time-dependent numerical simulation of ablation-controlled arcs

Gilligan, J.G.; Mohanti, R.

doi:10.1109/27.131019

Cited by 49 publications

(12 citation statements)

References 10 publications

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“…the energy transmission factor is a function of the heat of sublimation H sub , plasma internal energy U, plasma pressure P, and ρ is the plasma density [17][18][19][20][21][22], however, it has a manual entry into the code such that each code run can be at a selected transmission factor. The fraction of the energy absorbed by the vapor shield layer is stored as internal energy which causes expansion of the vapor layer against the incoming plasma flux due to the large pressure.…”

Section: Electrothermal Plasma Theory and Experimentsmentioning

confidence: 99%

“…The set of equations describes the balance of masses, momentum and energy from the formation of the plasma inside the plasma source and through its traveling along the entire length of the plasma source. Various 0-D and 1-D models were developed by several researchers [20,21,[23][24][25] and the details of the governing equations of the ETFLOW code and its developmental history can be found elsewhere [6,8,[17][18][19][20]. In this study, different values of the incident heat flux were incorporated in the electrothermal plasma code (ETFLOW code) through varying the values of the transmission factor f between a minimum of 0.2 meaning that 20% of the incident energy reaches the wall and 80% is absorbed in the vapor boundary layer, and its maximum of 1.0 meaning 100% of the energy is reaching the wall without any absorption in the vapor layer.…”

Section: The Etflow Codementioning

confidence: 99%

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Radiative Heat Transport through Vapor Plasma for Fusion Heat Flux Studies and Electrothermal Plasma Sources Applications

Bourham¹

2014

J Nucl Ene Sci Power Generat Technol

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High heat fluxes of up to 100 GW/m 2 and greater over a discharge period of 100 to 1000 µs can be generated from electrothermal (ET) plasma sources from the confined arc discharge. Sources with input energy of 10 kJ in a miniature capillary (4 mm radius and 9 cm length) are capable of producing 88.33 GW/m 2 heat flux inside the capillary, higher heat fluxes can be generated for higher input energies. Such high heat fluxes are adequate to simulate the energy deposition during hard disruptions in future fusion tokamak reactors, which result in erosion and thermal deformation of the surfaces of the critical internal components of the reactor. Calculation of the eroded mass due to intensive transient radiative heat transport to the surfaces is very critical in terms of the determination of the performance, durability and the life time of these components. Short intense high heat flux causes surface melting and vaporization. The vapor boundary layer absorbs a fraction of the incident heat flux which results in reducing the overall erosion. The transmitted fraction has a strong dependence on the energy input to the electrothermal source, which is used as a simulator for high heat flux deposition of plasma facing materials. The ETFLOW code models the plasma formation and calculates the plasma parameters for corresponding values of the transmission factor. Comparing experimental measurements to the computationally calculated mass erosion of the ET source material has verified the partial deposition of the incident heat flux. The energy transmission factor through the vapor boundary layer is found to be between 20% -60% for discharge current above 30 kA and between 60% -80% for less than 30 kA. The time of peak discharge current is set to be the time at which the transmission factor is evaluated.applications of such sources as mass accelerators, space minithrusters, propulsions and as high heat flux sources [1][2][3][4]. The heat fluxes generated in electrothermal sources can vary from as low as 5 GW/m 2 to as high as 100 GW/m 2 and greater, making such devices excellent simulators to study high heat flux erosion of plasma-facing components in fusion tokamak reactors [4,5].

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Section: Electrothermal Plasma Theory and Experimentsmentioning

confidence: 99%

Section: The Etflow Codementioning

confidence: 99%

Radiative Heat Transport through Vapor Plasma for Fusion Heat Flux Studies and Electrothermal Plasma Sources Applications

Bourham¹

2014

J Nucl Ene Sci Power Generat Technol

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“…Capillary discharges are efficient sources of high-density (5x10 25 -5x10 26 m -3 ), high-temperature (2-8 eV) pulsed plasmas which are being developed for a wide range of applications including optical guides for high power lasers 7 and x-ray sources 8 for low pressure capillary discharges and electro-thermal-chemical guns [9][10][11][12][13] for highpressure capillary discharges. Capillary discharges maintain a resistive arc through a narrow insulating capillary by the continual ablation of the capillary wall material or by injected mass.…”

Section: B Capillary Discharge and Coaxial Electrothermal Ppt Develomentioning

confidence: 99%

Capillary Discharge Based Pulsed Plasma Thrusters (Preprint)

Cambier¹,

Young²,

Pekker³

et al. 2007

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)Air Force Research Laboratory (AFMC) AFRL/PRS SPONSOR/MONITOR'S Pollux Drive NUMBER(S)Edwards AFB CA 93524-7048 AFRL-PR-ED-TP-2007-400 DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution unlimited (PA #07937A). SUPPLEMENTARY NOTESFor presentation ABSTRACTAlthough pulsed plasma thrusters have significant experimental heritage over a range of power levels, more recently they are often described as attractive low-power thrusters due to their small dimensions, simplicity, and ability to provide high specific impulses at low power levels. This paper, however, discusses research into the potential application of an electrothermal capillary discharge as a pulsed plasma generator useful in high-power spacecraft propulsion. A 0D transient physical model of the capillary discharge was constructed and used to characterize the operational envelope of the capillary discharge. Fundamental experimental investigations were also conducted to demonstrate the performance of the polyethylene capillary discharge over a range of energy/shot levels (500-1500J), capillary lengths (4cm-10cm), and LRC circuit inductances (10μH-40μH). The experimentally measured parameters (voltage difference, current, ablated mass, plasma temperature, and electron number density) typically agreed with the model predicted values to within 20%. Thruster relevant performance calculations were made using the validated model and showed that even without nozzle expansion the capillary discharge can operate as an efficient (30-40%) source of highpressure (>100 atm) plasma for use in spacecraft propulsion systems. Abstract: Although pulsed plasma thrusters have significant experimental heritage over a range of power levels, more recently they are often described as attractive low-power thrusters due to their small dimensions, simplicity, and ability to provide high specific impulses at low power levels. This paper, however, discusses research into the potential application of an electrothermal capillary discharge as a pulsed p...

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“…The ablative capillary discharges that have been previously studied as potential electro-thermal and electrothermo-chemical gun devices by various investigators since the mid-1980s see [1][2][3][4][5][6][7][8][9][10][11] and references therein, satisfy both of these conditions well. These studies investigated the dynamics of high-pressure ablative plasma discharges; they gave pressures in a range of 0.1-1 GPa and temperatures of the order of 1-3 eV.…”

Section: Introductionmentioning

confidence: 99%

“…In all theoretical models of ablative capillary discharges [1][2][3][4][5][6][7][10][11][12][13][14][15] zero-and one-dimensional, the thickness of the transition layer, Fig. 1, is assumed to be negligibly small compared to the inner capillary radius and the radial distributions of plasma parameters in the plasma core, Fig.…”

Section: Introductionmentioning

confidence: 99%