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Газодинамика импульсной электрической дуги во внешнем магнитном поле
Докладчик(и): Моралев И.А. Дата, время проведения: 07 февраля 2019, 11:00 Адрес: Ижорская ул., 13 стр.2. корп.Л1 к.224 Electric arc in the magnetic field is widely used in the applications of the flow heating and mixing in plasma torches, plasmachemical reactorsm e.t.c. The latter research considers constricated arc filament as a possible element for flow control in aerodynmic aplications, i.e. for boundary layer separation control. The flow in the vicinity of the channel is governed by the Ampere body force and heat release terms present inside the conductive arc channel that are balanced by the heat and momentum exchange on the pouter part of the arc. Resulting flowfield consists of the pair of vortices inside the conductive region separated from the external flowfield by the separatrix. The paper focuses on the details of the process in the case when the arc is driven with a current pulse of a limited duration. It is shown that in this case the process can be divided into the several stages, namely conductive channel formation and primary expansion, arc movement in the magnetic field, relaxation of the flow after current termination and flow evolution after the pulse. It is shown that during the pulse the flow in some vicinity of the arc is not significantly different from the stationary case. During this stage, high gas velocity can be attained in the cold gas (up to 100m/s), nearly equal to the arc displacement speed. After the termination or reduction of driving current, relaxation of the flow occurs via the rarefaction wave travelling through the gas. This rarefaction wave reduces the gas velocity down to tens of m/s. The flow pattern left in the interaction region constitutes a system of vortices on the border of the heated cavern of the arc. The study is performed both experimentally, using PIV methods, electric and otical measurements of arc properties and numerically via investigation of the problem in the MHD formulation. The paper includes the parametric study of the process with arc current, magnetic field and sort of the gas used as a parameters. The applicability of the arc in the transversal field for the momentum and mass transfer in boundary layer flows is discussed. |