Structure of hydrogen compression plasma flows in a magnetoplasma compressor

Abstract

Introduction. This paper is a continuation of [1-5], which dealt with the dynamics of compression plasma flows (CPFs) in magnetoplasma compressors (MPCs). Air CPFs were considered in [i, 3]. A two-dimensional model was proposed for describing the dynamics and structure of partially ionized radiating CPFs. The model was based on the coarse-particle method, introducing a magnetic field [6] and taking energy transfer by radiation into account within the framework of the two-flow multigroup approximation [7]. Calculations with this model determined the dynamics and structure of discharge in air and its principal radiative characteristics. Inclusion of the radiation has been shown to have a substantial effect on the plasma parameters in the compression region, considerably increasing the degree of plasma compression and lowering its temperature. In [2, 4, 5] this approach was used to describe the dynamics and structure of hydrogen CPFs. The work on the computational modeling of CPFs was started by Brushlinskii and Morozov [8]; the first studies considered hydrogen plasma (fully ionized). Those studies determined the qualitative features of the behavior of a CPF in an MPC. The dynamics of hydrogen CPFs with allowance for ionization was studied in [8-10]. This was done by using the approximation of discontinuous complete ionization of a plasma upon passage through a certain temperature T* [8, 9] or the modeling was done with detailed calculation of ionization from the Saha equation, but in the quasi-one-dimensional approximation [I0]. The radiation of the plasma was not taken into account. The first calculations from two-dimensional models of hydrogen CPFs with allowance for the partial ionization and energy transfer by radiation were described in [2, 4, 5]. The dynamics and structure of hydrogen CPFs, generated by MPCs at low (20-100 kA) currents were calculated in [4]. The effect of boundary conditions on the results of computational modeling were considered in [5], where good agreement between theoretical and experimental results was demonstrated. Here we have studied the dynamics and structure of a CPF in the general case (without restrictions on the current) for the operation of an MPC under various conditions. Fairly extensive experimental data have been accumulated to date on the processes in an MPC. The most complete experimental results on hydrogen CPFs were published in series of studies [11-14], [2, 15-17], and [18, 25]. The results of computational modeling for the conditions of [2, 15-17] were described in [2, 4, 5] and this paper considered the modes and conditions under which the first experiments [11-14] were carried out and which are characterized by high discharge currents. A more detailed exposition of the development of work on computational modeling of gas as CPFs and references to studies on the calculations of erosion plasma flows can be found in the reviews [8, 19, 20] and in [3-5].