MACH2 simulations of cablegun and PPT-4 geometries

Summary form only given. The computational code MACH2 was used to simulate the plasma flow in cableguns and a pulsed plasma thruster (PPT-4, developed at the University of Illinois at Urbana-Champaign) and the computed results were compared to the experimental operation of the devices. The capabilities of MACH2 were extended by incorporating a new radiation model as well as new thermodynamic equation of state tables for plasmas containing either Teflon or a mixture of 39% Teflon and 61% copper (by mass). In developing the tables, the thermodynamic variables at low temperatures were calculated using the NASA Equilibrium Code (CEA). The high temperature calculations were performed by iterating the multi-component Saha equation. Cubic polynomials were then used to blend the high and low temperature calculations together over the intermediate temperature regions. The Saha-calculated specific heats contained large numerical fluctuations and were filtered using a (1,1)-fold trimmed mean filter. The data was also smoothed over suitable temperature intervals using cubic polynomials. Using spectroscopic data gathered in the cablegun experiments at UTSI, a preliminary analysis was performed to obtain a rough estimate of plasma temperature.