Development of equation-of-state and transport properties for molecular plasmas in pulsed plasma thrusters. II - A two-temperature equation of state for Teflon

Schmahl, C. S.; Turchi, P. J.; Mikellides, Pavlos G.; Mikellides, Ioannis G.

doi:10.2514/6.1998-3662

Cited by 7 publications

(7 citation statements)

References 3 publications

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“…Having calculated the plasma density and electron temperature (Eqs. 1-3) one can calculate the chemical plasma composition considering Local Thermodynamic Equilibrium (LTE) in the way described previously 18,19 . In the considered range of electron temperature (1-2 eV) and plasma density (10 24 -10 26 m -3 ) it is assumed that polyatomic molecules C 2 H 4 are fully dissociated and we will start our consideration from the point when we have a gas containing atoms of C and H. The distribution of the atoms, multiply ionized ions, and electrons obeys the corresponding Saha equation.…”

Section: The Ablation-controlled Discharge Modelmentioning

confidence: 99%

Ablation Study in a Capillary Sustained Discharge

et al. 2007

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Abstract-Electrothermal-chemical (ETC) ignitionsystems have been demonstrated in gun systems to provide desirable characteristics including reproducible shorter ignition delays. The optimum combination of capillary tube and fuse wire properties has not been identified yet. We present a combined theoretical and experimental study of the capillary discharge with an aim to develop a capillary plasma source with efficient energy conversion. The major emphasis in the present capillary discharge model is the ablation phenomenon. Consideration is given to different characteristic subregions near the ablated surface: namely, a space-charge sheath, a Knudsen layer, and a hydrodynamic layer. A kinetic approach is used to determine the parameters at the interface between the kinetic Knudsen layer and the hydrodynamic layer. Coupling the solution of the nonequilibrium Knudsen layer with the hydrodynamic layer provides a self-consistent solution for the ablation rate. According to the model predictions, the peak electron temperature is about 1.4 eV, the polyethylene surface temperature is about 700 K, and the pressure is about 10 MPa in the case of a 0.6 kJ discharge. In parallel, a parametric experimental study of the capillary ablation process is conducted. The ablation rates are measured for capillary tubes made of polyethylene and Teflon. Both experimental measurements and simulations indicate that the ablated mass increases with the peak discharge current and that a smaller diameter capillary yields a larger ablated mass. It is found that model predictions agree well with experimental measurements. Report Documentation PageForm Public reporting burden for the 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 the 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 Washington Headquarters Services, Directorate for Information Operations and Reports, 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 a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

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Section: The Ablation-controlled Discharge Modelmentioning

confidence: 99%

Ablation Study in a Capillary Sustained Discharge

et al. 2007

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“…The following equations are the (9) reactions considered in this model that constitute the reaction path, as shown in Table II. 17) Writing these reactions in terms of equilibrium relations for the partial pressures.…”

Section: Thermochemical Modelmentioning

confidence: 99%

Numerical investigation on plume expansion, components evolution and ionization of polytetrafluoroethylene (PTFE) irradiated by nanosecond laser

Zhang¹,

Wu²,

Ou³

et al. 2020

Jpn. J. Appl. Phys.

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To investigate the plume expansion, components evolution and ionization in the laser ablation pulsed plasma thruster, which is difficult to obtain from experiments, the non-Fourier heat conduction model, fluid dynamics model and thermochemical model are established. The non-Fourier heat conduction model is established to calculate the propellant ablation, taking into account temperature dependent material properties, phase transition, depolymerization of polytetrafluoroethylene propellant, the reflection of the laser beam at the surface of the propellant, and non-Fourier effect. The fluid dynamics model is established to calculate the plume expansion, taking into account plume absorption and shielding. The thermochemical model is established to calculate the components evolution and ionization, taking into account nine chemical and ionization reactions with 12 components. By coupling the three models, the thermochemical characteristics, plume expansion and ionization of polytetrafluoroethylene irradiated by a nanosecond laser are numercially calculated.

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“…Having calculated the plasma density and plasma temperature (Eqs. 1-3) one can calculate the chemical plasma composition considering Local Thermodynamic Equilibrium (LTE) in the way described previously 8,9,12,13 . We start our consideration from the point when we have a gas At the power density level of 10 10 Wm -2 realized in the micro-laser plasma thruster 1 , the main mechanism of plasma absorption and therefore electron heating is the inverse bremsstrahlung.…”

Section: Figure 2 Schematic Of the Model In T-mode (Not To Scale)mentioning

confidence: 99%

Plasma Generation and Plume Expansion for a Transmission-mode Micro-laser Ablation Thruster

Keidar

Boyd²,

Luke³

et al. 2003

39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit

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An end-to-end model is presented of the transient plume created by a micro laser-ablation plasma thruster. In this paper we describe a model of the plasma generation and expansion for a microlaser plasma thruster operated in transmission-mode (T-mode). The laser ablation and plasma formation processes are modeled using a kinetic ablation model. This procedure provides boundary conditions at the target surface for the plume model that is based on a particle computational approach. The present study considers a 2.5-8 W diode-based laser irradiating a poly-vinyl chloride target over a rectangular focal spot of 30 x 120 µm for a pulse length of 3-10 ms. The plume simulations reveal many details of the multi-component plasma expansion. The results are compared with experimentally obtained plume signatures. Generally good agreement between experimental and calculated flux profiles is found.

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Development of equation-of-state and transport properties for molecular plasmas in pulsed plasma thrusters. II - A two-temperature equation of state for Teflon

Cited by 7 publications

References 3 publications

Ablation Study in a Capillary Sustained Discharge

Ablation Study in a Capillary Sustained Discharge

Numerical investigation on plume expansion, components evolution and ionization of polytetrafluoroethylene (PTFE) irradiated by nanosecond laser

Plasma Generation and Plume Expansion for a Transmission-mode Micro-laser Ablation Thruster

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