High energy pulsed inductive thruster modeling operating with ammonia propellant

Abstract

Numerical modeling of the pulsed inductive thruster operating with ammonia propellant at high energy levels, utilized a time-dependent, two-dimensional, and axisymmetric magnetohydrodynamics code to provide bilateral validation of experiment and theory and offer performance insights for improved designs. The power circuit model was augmented by a plasma voltage algorithm that accounts for the propellant’s time-dependent resistance and inductance to properly account for plasma dynamics and was verified using available analytic solutions of two idealized plasma problems. Comparisons of the predicted current waveforms to experimental data exhibited excellent agreement for the initial half-period, essentially capturing the dominant acceleration phase. Further validation proceeded by comparisons of the impulse for three different energy levels, 2592, 4050, and 4608J and a wide range of propellant mass values. Predicted impulse captured both trends and magnitudes measured experimentally for nominal operation. Interpretation of the modeling results in conjunction to experimental observations further confirm the critical mass phenomenon beyond which efficiency degrades due to elevated internal energy mode deposition and anomalous operation.

2D Magnetohydrodynamics simulations of induced plasma dynamics in the near-core region of a galaxy cluster

“…to maintain its divergence at an acceptably small level (solenoidal condition) uses a successive over-relaxation solver to iterate on the in-plane components towards ∇ · B = 0 by solving for the scalar potential φ (elliptic correction since a Poisson's equation is solved), and is based on the method proposed by Brackbill & Barnes (1980). In the last three decades, MACH2 has been employed to study a variety of plasma problems some of which include plasma opening switches (Buff et al 1987;Degnan et al 1987), gas and solid density z-pinch implosion physics (Degnan et al 1995;Shumlak, Hussey & Peterkin 1995), very high power plasma source designs (Mikellides, Turchi & Mikellides 2002b), magnetic nozzles (Mikellides et al 2002a) and a variety of plasma thrusters (Mikellides, Turchi & Roderick 2000;Turchi et al 2000;Mikellides & Villarreal 2007).…”

Numerical simulation on the operational characteristics of the pulsed inductive acceleration

“…The simulation results here were obtained using the ideal excitation current curve, varying in a sinusoidal form, which is capable of predicting the flow characteristics in the first half cycle, while in the second half cycle the excitation current is strongly affected by the plasma load, and the curve deviates from the sinusoidal form apparently, as illustrated in ref. []. The incorporation of the self‐consistent circuit model considering the plasma resistance into the MHD model to simulate the flow is our future aim.…”

“…These two occurrences influence the design of inductive coil, especially the coil size, as the radius of the PIT increased from 0.1 m in the initial design to 0.5 m in the latest prototype to obtain a lager decoupling distance. Meanwhile, to give insights into the field structures and predict the performance with varying pulsed energy, which are difficult to measure in experiments, the MACH2 MHD code, using a semi‐empirical thermodynamic theory and the classical transport model, was employed by Mikellides et al, and special attention was paid to MarK V and Mart Va prototypes. The performances of monatomic gases Ar and He and the polyatomic gas NH 3 were evaluated, and the model was validated by experimental results at different initial mass and energy levels.…”

State-of-the-Art and Advancement Paths for Inductive Pulsed Plasma Thrusters

“…Mikellides et al [65][66][67] performed 2-D axisymmetric modeling using the multiblock arbitrary coordinate hydromagnetic (MACH) code. This was the first major time-dependent simulation of the plasma evolution using an MHD solver, though a pair of upgrades had to be implemented during the course of the research to improve the results.…”

“…This was the first major time-dependent simulation of the plasma evolution using an MHD solver, though a pair of upgrades had to be implemented during the course of the research to improve the results. In the most recent simulations, at each timestep the computed magnetic field and plasma resistivity were integrated over the solution domain and used to insert the effects of time-varying resistive and inductive plasma circuit voltage losses into the model governing the solution for the time-dependent external circuit current [67]. Also, a new non-equilibrium equation of state model for ammonia was developed and included to more accurately model the MK Va data [68].…”