Numerical and experimental investigations on thermal interaction between thermal plasma and solid polymer powders using induction thermal plasma technique

Abstract

Abstract. Interaction between thermal plasma and polymer solid powders was investigated using inductively coupled thermal plasma (ICTP) technique. Interaction between thermal plasmas and polymers is extremely important, for example, for design of down-sized circuit breakers, because it fundamentally affects the interruption capability of the circuit breakers. The ICTP technique was used in the present work because it presents the advantages of no contamination and good repeatability. The polytetrafluoroethylene (PTFE), polymethylmethacrylate (PMMA), polyethylene (PE), and polyoxymethylene (POM) were treated as polymer materials. Numerical modelling for injection of polymer solid powders into Ar thermal plasma was also made including thermal interactions between thermal plasmas and polymer powders. Results showed that PMMA-ablated vapour has a higher plasma-quenching efficiency than others; the polymer solid properties affect the plasma-quenching ability indirectly. Comparison of the calculated results to experimental results, showed good agreement from the viewpoints of the spatial distribution of ablated vapour concentration and the average solid particle velocity.

Numerical Simulation of Solid Particle Ablation in Thermal Plasmas using CIP‐VOF Method

“…Transport properties of 100%Ar and 100% ablated vapor were calculated using the first order approximation of the Chapman-Enskog method (5) . Thermodynamic properties such as the mass density ρ, the specific heat at constant volume C v , the sound velocity at constant temperature C sT , and the gas constant R were calculated using the calculated equilibrium composition (5) .…”

“…Thermodynamic properties such as the mass density ρ, the specific heat at constant volume C v , the sound velocity at constant temperature C sT , and the gas constant R were calculated using the calculated equilibrium composition (5) . For the specific heat at constant volume C v , for example, the following relation was used.…”

“…This paper describes a PE particle in Ar thermal plasmas because we have actually studied the interaction between the PE particles and Ar thermal plasmas in other experiments to study the plasma quenching effect of polymer ablated vapors (5) . The PE particle can be ablated easily because of its lower latent heat for ablation.…”

“…This rapid ablation mate-rial is suitable for fundamental studies of ablation phenomena. Moreover, to date, we have studied ablation phenomena of solid polymer particle in thermal plasmas experimentally to investigate effects of ablated vapor on quenching of thermal plasmas (5) , and in which the interactions between polymer powders and the thermal plasmas are important for the fundamental study of ablated vapor effects on the plasma temperature in our previous paper (5) . The calculation results presented herein demonstrate that strong ablation occurs at the upstream particle surface, which produces a strong gas flow; then the particle shape changes with time.…”

Influence of emissivity on behavior of metallic dust particles in plasmas

“…Such emissivity can be found in the literature, 33 and is often used as a constant value for some applications to bulk metals, for temperature determinations in experiments 34 or numerical simulations of the dust dynamics. 35 For present calculations, we assumed the constant total emissivity to be 0.1 for Li, 0.15 for Be, 0.35 for stainless steel, 0.2 for Mo, and 0.4 for W. 33 However, the adoption of the constant emissivity may lead to significant differences for small particle calculations, because the particle emissivity may have strong size and temperature dependences.…”