Modeling of argon–steam thermal plasma flow for abatement of fluorinated compounds

Abstract

This study presents a numerical model of the hybrid–stabilized argon–steam thermal DC plasma torch of a new design for generating an argon–steam plasma suitable for efficient abatement of persistent perfluorinated compounds (PFCs). The model includes the discharge region and the plasma jet flowing to the surrounding steam atmosphere contained in a plasma-chemical chamber. Compared to previous studies, the torch had a smaller nozzle diameter (5.3 mm) and a reduced input power (20-40 kW) and arc current (120-220 A). The outlet region for the plasma jet extends to 20 cm downstream of the exit nozzle. Fluid dynamic and thermal characteristics together with diffusion of argon, hydrogen and oxygen species, and distribution of plasma species in the discharge and the plasma jet are obtained for currents from 120 to 220 A. The results of the calculations show that the plasma jet exhibits high spatiotemporal fluctuations in the shear layer between the plasma jet and colder steam atmosphere. The most abundant species in the plasma jet are hydrogen and oxygen atoms near the jet center, and molecules of H2, O2 and OH in colder surrounding regions. Satisfactory agreement is obtained with measurements of the radial temperature and electron number density profiles near the jet center close to the nozzle exit.

Research progress on numerical simulation of arc discharge plasma process

“…The results exhibited that the length of arc decreased and the arc radius increased as working current increases, resulting in the increase of plasma velocity and temperature, the results are in good consistent with the measured ones. Jenista et al [14] simulated Ar-H 2 O plasma mixing in Ar vapor arc discharge of plasma generator by using H 2 O vortex and Ar to stabilize the arc together. In this model, the diffusion of plasma species was described by combining diffusion coefficients, and the results exhibited that Ar gas was mainly distributed near the arc axis and the mixture of Ar and hydrogen and oxygen is uneven when the calculated current was 150-400 A and Ar was 15-21.5 slpm.…”

“…Therefore, these physicochemical characteristics put forward the severe challenge to the computational model and simulation of arc discharge. In addition, the process parameters often affect the performance of ADP technology applied in the practical processing, including external magnetic field [10,11], working current [12,13], external airflow [14,15], electrode gap [16,17], etc. Moreover, the instantaneous physical state parameters, the position of the material, the distance between electrodes have changed with space and time after each discharge period, which will have a great impact on the next discharge process.…”

Transforming a Computational Model from a Research Tool to a Software Product: A Case Study from Arc Welding Research

“…Many researchers have developed plasma modelling codes, for example, for thermal plasma processes [9], including nanoparticle production [10][11][12], plasma jet formation [13], and waste destruction [14], as well as low-pressure plasma processes for applications such as semiconductor etching [15,16], deposition [16], and lighting [17].…”