The effect of geometry of a two-chamber electrode on gas dynamics in an arc plasmatron duct
I.D. Grishko1,2, S.P. Vashchenko1, D.Yu. Batomunkuev1, O.B. Kovalev1
1Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: plasmatron, vortex flow, turbulence, two-chamber electrode, CFD-simulation
Abstract
Methods of 3D numerical simulation were applied for evaluating the flow dynamics in the internal electrode of a plasmatron with a two-chamber design while a “cold” blowout through the electrode. This study presents spatial distributions for the gas flow velocity, turbulence kinetic energy and the pressure inside the two-chamber electrode equipped with two swirlers (they provide tangential input for plasma-forming air flow). Variations in the gas velocity for transversal cross-sections of the arc chamber are in agreement with previously published data for the case of “cold” smoke-based blowout of the two-chamber plasmatron equipped with a cylindrical electrode. It was established that the cylinder-conical shape of the internal electrode might result in a shorter initial laminar column in the electric arc; this happens due to expansion of the turbulent interval at a fixed length of the arc. Experiments in a plasmatron with an inter-electrode insert demonstrated that the cylinder-and-cone shape of the electrode causes a higher (by 30-35 %) voltage on the plasmatron as compared with the cylinder-only shape of the electrode. This is a qualitative confirmation for calculated results about a higher kinetic turbulence energy and a wider turbulent zone of the electric arc occurring in a two-chamber design plasmatron.
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