Modeling of the cathode jet of a high-power transferred arc

Abstract

A physical model of two zones (constricted arc' and cathode jet) of a I-MW transferred arc in air is presented. It is based on the solution of consert,ation equations by a.finite-difference method. Turbulence is treated with Prandtl's approximation, whereas radiatit,e tran.sJ-er is solved considering a nonhomogeneous nlediunl, with the hypothesis of gray spectral bands. The inlluence of radiatit, e transler on the temperatare field is illustrated using two-band and lbur-band radiation models.We also show the ir~[luence t~f set,eral parameters on plasma .jet properties: current intensity between 500 and 1500 A: gas rnass flow rate between l O and 90 g/s; vortex injection. The arc characteristics are analyzed in accordance with physical mechanisms such as heat conduction, radiation, turbulence, confection, and mixing qf cold gas.

Swirling flow and its influence on dc arcs in a duo-flow hybrid circuit breaker

“…A comparative study of the two most often used turbulence models (the K-ε model and the Prandtl mixing length model) by Yan et al [21] indicates that the Prandtl mixing length model is sufficiently accurate to describe the turbulent arc plasmas in strong gas flow. Following Lilley [22] and others [2][3][4], we assume isotropic turbulence in the swirling arc flow. The turbulent viscosity is given by…”

“…Swirl is used extensively in combustion chambers and industrial arc furnaces as a means of controlling the size, shape and stability of a flame [1] or arc column [2][3][4]. The swirling flow in these devices is usually induced by injecting gas in the azimuthal direction of an axisymmetric chamber.…”

“…Although the fundamental governing equations are similar, the electric arc burning in a hybrid circuit breaker has several distinctive features when compared with the cases studied in [2][3][4]. The most important difference lies in the mechanism that generates the swirling flow.…”

“…As a consequence, a swirling flow is developed in the electrically conducting column. Whereas in the latter cases, swirling is maintained by continuously injecting gas in the azimuthal direction from an inlet near the wall [1][2][3][4]. A fundamental difference therefore needs to be recognized: swirling is initiated in the low density, high temperature column in the switching arc case by a body force while it is maintained by an azimuthal directed mass source of cold gas in the other cases studied in [1][2][3][4].…”

Two-dimensional turbulent heat and fluid flow model to study effect of working gas and other process parameters on heat transfer in plasma furnace

“…Some of the models assume the flow to be laminar, 1,2 while others assumed it to be turbulent. [3][4][5][6][7][8][9][10] Langerman and Lemmon 11 calculated the velocity and temperature profile of the inner portion of a non-transferred torch. Some of the models assume that the arc is stationary.…”