Radiation transport in ionizing gas flow within the quasi-steady plasma accelerator

Numerical study of the hydrogen ionization process in the channel of the quasi-stationary plasma accelerator is presented. Calculations of pulsating and stationary flows of ionizing hydrogen were carried out within the framework of two-dimensional MHD model in the approximation of local thermodynamic equilibrium, taking into account the radiation transport and under the condition of uniform gas supply at the channel inlet. As a result of a series of calculations, the empirical condition for the stationarity of axisymmetric flows of ionizing hydrogen was determined.

Download Full-text

Untersuchung quasistationärer Lichtbögen hoher Leistung bei starker axialer Gasströmung / High Power Quasistationary Arcs in Strong Axial Gasflow

Zeitschrift für Naturforschung A ◽

10.1515/zna-1972-1009 ◽

1972 ◽

Vol 27 (10) ◽

pp. 1433-1439 ◽

Cited By ~ 5

Author(s):

W. Bötticher ◽

U. Kogelschatz ◽

E. Schade

Keyword(s):

High Power ◽

Gas Flow ◽

Discharge Chamber ◽

Radiation Transport ◽

Gas Flows ◽

Radial Temperature ◽

Divergent Flow ◽

Rectangular Distribution ◽

Stable Part ◽

Cool Region

Abstract A new discharge chamber for pulsed arcs of high power (U=1000V, 1-2 . . . 5 kA) burning quasistationary in strong axial gas flows is described. The axial pressure drop of about 25 at in the convergent-divergent nozzle results in a mass flow of ca. 600 g/s. The pulse duration is 5 ms. In front of the nozzle one can produce a very stable arc column under certain conditions. In the divergent flow field the arc generates strong turbulence. The radial temperature distribution in the stable part is measured by schlieren-and emission spectroscopic methods. Due to radiation transport in the arc column proper and radial gas flow in the cool region the temperature profile is almost a rectangular distribution.

Download Full-text

Hydrodynamically-Enhanced Light Intensity Distribution in an Externally-Irradiated Novel Aerated Photoreactor: CFD Simulation and Experimental Studies

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.1703 ◽

2008 ◽

Vol 6 (1) ◽

Cited By ~ 3

Author(s):

Francisco J Trujillo ◽

Ivy A-L Lee ◽

Chen-Han Hsu ◽

Tomasz Safinski ◽

Adesoji A Adesina

Keyword(s):

Transport Equation ◽

Gas Flow ◽

Cfd Simulation ◽

Liquid Mixture ◽

Radiation Transport ◽

Specular Reflection ◽

Fluid Dynamic ◽

Experimental Studies ◽

Incident Radiation ◽

Radiation Transport Equation

The enhancement of the surface incident radiation on the walls of an externally-irradiated bubble tank photoreactor was studied and modeled by solving the radiation transport equation (RTE) in conjunction with the continuity, momentum and k-e turbulence equations. Computational fluid dynamic (CFD) simulation results were complemented with actinometric runs to determine the effect of the gas flow rate on the radiation loss by reflection at the surface of the gas-liquid mixture due to bursting of the bubbles. The model assumed that the gas-liquid mixture is a semitransparent medium where the light is scattered as a result of specular reflection and refraction when the light rays impinge on the air bubbles. The superficial reflectivity at the top of the gas-liquid mixture was linearly correlated with the superficial gas velocity. In particular, the simultaneous solution of the hydrodynamics and radiation transport equation using CFD allowed us to establish the relationship between the light scattering coefficient and the bubble size and the gas hold-up. The excellent agreement obtained between the experimental data and the CFD model validates the proposed model.

Download Full-text

Influence of Ionizing Gas Flow on Structural Homogeneity of Type IV Silica Glass

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.726.409 ◽

2017 ◽

Vol 726 ◽

pp. 409-413 ◽

Cited By ~ 1

Author(s):

Yuan Cheng Sun ◽

Xue Fu Song ◽

Xiu Rong Du ◽

Xiao Qiang Zhang ◽

Hui Wang ◽

...

Keyword(s):

Temperature Field ◽

Silica Glass ◽

Gas Flow ◽

Uniform Temperature ◽

Fictive Temperature ◽

Structural Homogeneity ◽

Type Iv ◽

Structural Network ◽

Uniform Temperature Field ◽

Ionizing Gas

Type IV silica glass is the key material in inertial navigation and optical field due to its high purity and unbroken structural network. Structural homogeneity of type IV silica glass, which is mainly affected by producing process, is one of the most important properties and determines its usability. The influence of ionizing gas flow of plasma was studied in this paper. Flow rate of working gas and protecting gas was changed and the depositing temperature field was measured. Structural homogeneity of deposited silica glass was discussed by optical homogeneity, fictive temperature and stress birefringence. Results show that more uniform temperature field can be obtained with higher working gas flow and lower protecting gas flow, and the structural homogeneity of type IV silica glass is better. But the proportion of working gas and protecting gas should not be larger than 2. When the working gas and protecting gas are 5 m3/h and 2.5 m3/h respectively, the structural homogeneity of type IV silica glass is the best.

Download Full-text

The study of helium ionization process stability in the channel of plasma accelerator

Keldysh Institute Preprints ◽

10.20948/prepr-2021-108 ◽

2021 ◽

pp. 1-24

Author(s):

Venyamin Sergeevich Konovalov

Keyword(s):

Numerical Study ◽

Plasma Accelerator ◽

Mhd Equations ◽

Ionization Process ◽

Gas Flows ◽

Process Stability ◽

Multiply Charged ◽

Integral Characteristics ◽

The Stability ◽

Ionizing Gas

Numerical study of the ionization process stability in a flow of ionizing helium in the channel of the quasi-stationary plasma accelerator is presented. The model of two-dimensional axisymmetric flows is based on the modified MHD equations for the multicomponent medium consisting of atoms, electrons, and multiply charged ions with different ionization multiplicity. The numerical model takes into account the electrical conductivity and thermal conductivity. Results of modeling of the ionizing gas flows and the integral characteristics of the radiation are presented. As a result of a series of calculations, the empirical condition for the stability of ionizing helium flows was obtained in terms of the experimentally measured parameters.

Download Full-text