Numerical Investigation of Hybrid-Stabilized Argon-Water Electric Arc Used for Biomass Gasification

Jenista, Jiri; Takana, Hidemasa; Nishiyama, Hideya; Bartlova, Milada; Aubrecht, V.; Křenek, Petr; Hrabovský, Milan; Kavka, T.; Sember, V.; Mašláni, A.

doi:10.5772/19267

Cited by 1 publication

(5 citation statements)

References 23 publications

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“…Two radiation models have been employed in our former calculations, the net emission coefficient and partial characteristics methods [51][52][53][54][55], as well as the large-eddy-simulation (LES) turbulent model [56][57][58] to check possible deviations from the laminar flow assumption. The results of the simulations confirmed, apart from the other results, a negligible effect of the tangential motion of plasma on the overall arc performance [59,60], existence of transition to supersonic flow regime at the plasma jet near the outlet nozzle orifice for currents higher than 400 A [61][62][63][64], and a quasi-laminar plasma flow structure in the discharge chamber and near the exit nozzle [57,58,65]. Comparison with available experimental data showed very good agreement for the radial temperature profiles and satisfactory agreement for the radial velocity profiles [63,64].…”

Section: Introductionsupporting

confidence: 57%

“…The results of the simulations confirmed, apart from the other results, a negligible effect of the tangential motion of plasma on the overall arc performance [59,60], existence of transition to supersonic flow regime at the plasma jet near the outlet nozzle orifice for currents higher than 400 A [61][62][63][64], and a quasi-laminar plasma flow structure in the discharge chamber and near the exit nozzle [57,58,65]. Comparison with available experimental data showed very good agreement for the radial temperature profiles and satisfactory agreement for the radial velocity profiles [63,64]. Evaluation of the Mach number from the experimental data for 500 and 600 A confirmed the existence of the supersonic flow regime [63,64].…”

Section: Introductionsupporting

confidence: 57%

“…Comparison with available experimental data showed very good agreement for the radial temperature profiles and satisfactory agreement for the radial velocity profiles [63,64]. Evaluation of the Mach number from the experimental data for 500 and 600 A confirmed the existence of the supersonic flow regime [63,64].…”

Section: Introductionsupporting

confidence: 53%

“…due to the gradients of mass density, temperature, pressure, and an electric potential. The results are compared with our former model neglecting species mixing [63,64] and with available experiments.…”

Section: Introductionmentioning

confidence: 99%

“…We begin the paper with an extended description of the physical model in section 2, boundary conditions in section 3, and present the most important findings in section 4, including a comparison with our former results [63,64] and available experiments. Our conclusions are given in section 5.…”

Section: Introductionmentioning

confidence: 99%

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Modeling of inhomogeneous mixing of plasma species in argon–steam arc discharge

Jenista

Takana

Uehara

et al. 2018

J. Phys. D: Appl. Phys.

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This paper presents numerical simulation of mixing of argon- and water-plasma species in an argon–steam arc discharge generated in a thermal plasma generator with the combined stabilization of arc by axial gas flow (argon) and water vortex. The diffusion of plasma species itself is described by the combined diffusion coefficients method in which the coefficients describe the diffusion of argon ‘gas,’ with respect to water vapor ‘gas.’ Diffusion processes due to the gradients of mass density, temperature, pressure, and an electric field have been considered in the model. Calculations for currents 150–400 A with 15–22.5 standard liters per minute (slm) of argon reveal inhomogeneous mixing of argon and oxygen–hydrogen species with the argon species prevailing near the arc axis. All the combined diffusion coefficients exhibit highly nonlinear distribution of their values within the discharge, depending on the temperature, pressure, and argon mass fraction of the plasma. The argon diffusion mass flux is driven mainly by the concentration and temperature space gradients. Diffusions due to pressure gradients and due to the electric field are of about 1 order lower. Comparison with our former calculations based on the homogeneous mixing assumption shows differences in temperature, enthalpy, radiation losses, arc efficiency, and velocity at 400 A. Comparison with available experiments exhibits very good qualitative and quantitative agreement for the radial temperature and velocity profiles 2 mm downstream of the exit nozzle.

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