Coupled radiative, flow and temperature-field analysis of a free-burning arc

Abstract

A computer simulation of a thermal plasma that utilizes a detailed line-by-line radiative analysis coupled to a flow and temperature-field analysis has been written. The radiative transport portion of the model uses the S-N discrete ordinates method and the required spectral radiative properties are calculated from basic atomic data. The flow and temperature-field portion of the calculation is handled using the finite-volume method. The thermal plasma configuration studied using this coupled model is a two-dimensional, axisymmetric, 200 A, 1 cm long, free-burning arc located in a one-atmosphere argon environment. Results from this analysis are compared with those from an uncoupled, line-by-line radiative analysis of this same arc and from a flow and temperature-field analysis that utilizes net emission coefficients to model the radiative source term. As thought, noticeable differences are found between results from the coupled and uncoupled analyses. This work proves that it is feasible to conduct two-dimensional, coupled, line-by-line calculations in a thermal plasma, but the computational times are large.

Formation of self-organized anode patterns in arc discharge simulations

“…This fact has motivated the use of a time-dependent and three-dimensional NLTE model in the present work. As stated in Section 1, the NLTE model is based on the chemical equilibrium assumption and uses relatively simple boundary conditions over the anode surface, and does not include the modeling of the bulk electrodes, electrode sheath models, or anode material evaporation effects [62][63][64][65][66][67][68][69]. nodes; therefore, the fine mesh has approximately 2 times the resolution and size of the base mesh.…”

“…Table 6 shows the values of J qmax and r cath for the values of I tot simulated (i.e., from 100 to 300 [A] in intervals of 25 [A]). A value of n cath = 4 has been used for all J qcath profiles, whereas a value of n cath = 1 has been traditionally used for sharply conical cathodes or truncated two-dimensional computational domains (e.g., [29,68,76] varies approximately linearly with I tot ; this functional dependency produces the expected behavior of the cathode jet [28], as described in the following section. T from Hsu and Pfender [29] (left).…”

“…The NLTE model describes the evolution and interaction of the heavy-species and electron temperatures using different energy conservation equations for the heavy-species and electrons, respectively. The model relies on the chemical equilibrium assumption, uses relatively simple boundary conditions over the anode surface (e.g., non-slip flow, convective heat transfer and constant electric potential), and does not include electrode sheath models, charge separation, modeling of the bulk electrodes, ambipolar diffusion effects, detailed radiative heat transfer, or anode material evaporation effects [62][63][64][65][66][67][68][69]76].…”

Numerical Modeling Of GMAW ARC

“…Many models have been developed to model the heat transfer and fluid flow in the arc plasma for both GTAW [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] and GMAW [19][20][21][22][23][24]. Mckelliget and Szekely [1], Choo et al [2] and Goodarzi et al [3] have simulated the arc column by assuming the current density distribution at the cathode surface in GTAW.…”

“…The simplified models [7][8] reduced the computation time to 1% of the original unified model and gave fair results in agreement with experimental results when 0.005-0.01 cm mesh size was chosen around the cathode tip. These simplified models have been used and further developed by many researchers [9][10][11][12][13][14][15][16][17][18] to calculate the heat transfer and fluid flow in the arc column.…”