Vittorio Colombo
Dipartimento di Ingegneria delle Costruzioni Meccaniche, Nucleari, Aeronautiche e di Metallurgia (D.I.E.M.) and C.I.R.A.M., Università degli Studi di Bologna, Via Saragozza 8, 40123 Bologna, Italy
Gianni G.M. Coppa
Istituto Nazionale per la Fisica della Materia and Dipartimento di Energetica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
Davide Bernardi
Universita degli Studi di Bologna, Dipartimento di Ingegneria delle Costruzioni Meccaniche, Nucleari, Aeronautiche e di Metallurgia (D.I.E.M.) and C.I.R.A.M., Via Saragozza 8, 40123 Bologna, Italy
The aim of the work is to investigate the basic phenomena of heat generation and transfer in inductively-coupled RF plasma torches working at atmospheric pressure. Many
fundamental works on the subject [1,2] propose a detailed treatment of the electromagnetic, temperature and velocity fields inside the torch. In the present work, in order to highlight the effects due to the distribution of the electromagnetic and temperature fields when separated
from the effect of the complex behaviour of the fluid circulation, simplified slab and cylindric
geometries for the cross section of the torch have been considered. The mathematical model takes into account heat conduction and convection, using a simplified expression for the velocity field; a two-dimensional treatment of the electromagnetic field is employed. The results presented refer to torch working near the minimum plasma sustaining power and well above threshold, showing temperature and power density distributions; comparisons between
results obtained using the exact two-dimensional treatment for the electromagnetic field and a simplified one-dimensional approach are presented. A simple model is also presented explaining why the transverse temperature profile tends to change its shape in order to induce
an increase of the mean power along the axial coordinate when the mean plasma temperature decreases.