Progress Towards an End-to-End Model of an Electrothermal Chemical Gun

Abstract

Much progress has been made in the last few years toward the development of an end-to-end computer model of an electrothermal chemical gun. Phenomena that must be considered in an electrothermal chemical gun model include the initial capillary plasma properties, the plasma-air interaction, plasma sheath effects, and the plasma-propellant interaction itself. This paper presents an overview of recent progress made modeling these various phenomena. Also discussed are methods under consideration to incorporate surface chemistry effects into the plasma-propellant interaction model.

Electrothermal tapered capillary hyper jet focused-injection plasma source concept

“…6 and 7, respectively. P exit peak ( MPa) = 222.83 e − 0.07 θ , R 2 = 0.95778 (6) v exit peak ( km/ s) = 6.22 e − 0.01 θ , R 2 = 0.99859 (7) The peak exit temperature and total number density are shown in Fig. 5, where the trend is again similar showing a decrease in the parameters with increased taper angle.…”

“…Elecrothermal capillary discharges used in most ETC experiments were cylindrical with an average length of 9-15cm and average diameter 4-10mm, and either operating in the ablation-controlled confined arc regime or fused with a thin aluminum wire as an exploding fuse to initiate the discharge [2], [3], [5], [8]- [11]. Pulse length varies between 0.1-1.0ms with discharge currents in the range of few kA to 100s kA, and can provide plasma pressure of several 100MPa, exit plasma velocities of up to 5km/s and greater, and plasma temperature in the range of 10,000-40,000 o K [3][4][5][6][7][8][9][10][11][12][13]. Modeling of these capillaries was either in 0-D or 1-D based on the assumption that the plasma temperature distribution is constant along the radius of the capillary [4]- [15].…”

“…Electrothermal capillary plasma discharges have been studied for various applications in launch technology from pure electrothermal mass accelerators (ETA) to hybrid electrothermalelectromagnetic launchers (ET-EM) and electrothermal-chemical (ETC) guns [1][2][3][4][5][6][7]. Electrothermal capillary plasma sources in the ETC guns were utilized as an igniter to the bulk-loaded propellant and as an augmentation mechanism to the burn rates of solid propellant [8]- [11].…”

Numerical Study of Plasma-Assisted Aerodynamic Control for Hypersonic Vehicles

“…The simulations are performed using second-order accurate spatial discretization and carrying double precision arithmetic throughout. LeMANS produces steadystate flow-field solutions using a first-order accurate time advancement scheme, thus small time steps and an appropriate CFL number ensure accuracy [63]. Time advancement is performed using either explicit, point implicit, or a line implicit advancement.…”

Study of the expansion characteristics of a pulsed plasma jet in air

“…When considering the chemical reaction of plasma air, a computational fluid dynamics simulation with 26 species and 60 reactions of an expanding capillary plasma jet for ETC gun application can be found in [23]. It also shows the importance of the plasmaair interaction in actual ETC implementation [24].…”