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Pulsed Plasma Acceleration Modeling in Detonation and Deflagration ModesGas-fed electromagnetic pulsed plasma accelerators discharge electrical energy into a gas to ionize and electromagnetically accelerate propellant in the domain. Efforts to model pulsed accelerators have either assumed that the discharge is short and completely tran- sient, accelerating the gas by entraining it in a moving current sheet, or that the discharge is relatively long, establishing a stable quasi-steady current distribution pattern that accel- erates a plasma flowing through it. There have been pulsed plasma accelerator tests that appear to fit somewhere between these two bounds, exhibiting some properties that are associated with the purely transient devices while also showing others that are associated with quasi-steady-state plasma acceleration. A model is presented based upon the premise that all pulsed plasma accelerators first form an accelerating current sheet (detonation mode accelerator). Depending upon the pulse length and the gas conditions in the dis- charge channel, the plasma sheet may reach the end of the accelerator before the discharge has completed a full half-cycle, wherein the proposed model transitions to a quasi-steady description of the acceleration process (deflagration mode accelerator). A review of the entire model is presented, highlighting improvements and upgrades implemented to aid in the stability of the numerical scheme used to model the gas flow in the channel and an im- proved treatment of current sheet mass shedding, which adds gas to the wake of the sheet. The assumptions employed to model the transition from detonation to deflagration mode are presented and used to generate solutions to the governing equations. The modeling of the deflagration-mode under the present assumptions results in very low deflagration im- pulse bits relative to those obtained at the end of the detonation mode, implying that the present assumptions and modeling of the deflagration mode may not represent a fruitful approach.

Document ID
20190032429
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Polzin, Kurt A.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Greve, Christine M.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Sankaran, Kamesh
(Whitworth Univ. Spokane, WA, United States)
Date Acquired
October 31, 2019
Publication Date
September 15, 2019
Subject Category
Plasma Physics
Report/Patent Number
M19-7645-2
IEPC-2019-A893
Meeting Information
Meeting: International Electric Propulsion Conference
Location: Vienna
Country: Austria
Start Date: September 16, 2019
End Date: September 20, 2019
Sponsors: Electric Rocket Propulsion Society
Distribution Limits
Public
Copyright
Public Use Permitted.
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