PLASIMO, a general model: I. Applied to an argon cascaded arc plasma

Abstract

A non-LTE argon cascaded arc plasma is studied and modelled with the general plasma simulation program PLASIMO. The structure of PLASIMO is flexible and transparent, so that apart from the study given in the present paper several other multicomponent stationary plasmas in a wide pressure range (10 −3 to 1 bar), from local thermal equilibrium (LTE) to non-LTE, and with different energy coupling mechanisms can be simulated as well. The modular structure is divided into three main parts: the transport part which forms the heart of the model, the plasma configuration part, and the composition part. The latter two parts define the input parameters for the transport part and are controlled by the PLASIMO user. The three parts are again divided into separate modules. The strong modularity makes PLASIMO easy to handle and easy to adjust or expand. Results of PLASIMO applied on the cascaded arc are compared with experimental data and show reasonable agreement. The influence of the boundary conditions on the simulation results is discussed.

Mach numbers for gases and plasmas in a convergent-divergent cascaded arc

“…However, we did not have to state the outlet Mach condition very accurately, since for supersonic outlet flows the outlet Mach number does not influence the upstream flow. 7,19 For subsonic flows an outlet Mach number of 0.9 has been used at first, as in case of straight arcs. 19 Unfortunately, the outlet Mach number had to be chosen more precisely for subsonic flows, as demonstrated by taking the outlet Mach number equal to 0.2 in Fig.…”

“…This heat is transported by the plasma and lost by cooling at the wall and at the arc channel outlet. [1][2][3][4]7,19 Cooling at the walls can be influenced by changing the wall temperature, which in fact changes the temperature gradient near the wall and, therefore, changes the heat conduction towards the wall. Note that by choosing the cooling at the wall (ϪdQ) equal to…”

“…To verify this statement, we will model gases and plasmas flowing through a convergentdivergent cascaded arc plasma source with a twodimensional model called PLASIMO. 19 The PLASIMO simulation model uses the control volume concept with conservation of fluxes to make the transport equations discrete. In the quasi one-dimensional model, as used in previous sections, the volumes cover the whole cross section.…”

Numerical simulation of a cascaded arc source with different Ar–H2 mixtures of nonlocal thermal equilibrium plasmas

“…The PLASIMO code used provides us a steady state twodimensional ͑2D͒ hydrodynamical model, based upon the following equations: [10][11][12] ͑1͒ the particle balance equations for heavy species ͑ions and neutrals͒; ͑2͒ the continuity equation for the bulk plasma; ͑3͒ the momentum balance equation for the mixture; This set of equations is solved with a finite volume approach. For the details we refer to Refs.…”

“…8,9 Chemistry and flow forms a complex system and create hinders in the optimization of the arc. To obtain a better understanding and to assist in optimization, previously, we have modeled the cascaded arc of Pilot-PSI using the PLASIMO code 10,11 and studied its properties for pure argon and hydrogen gases. 12 That study was mainly focused on the effect of axial magnetic field and geometry on the ion yield.…”