In this paper numerical simulation is performed to investigate the effects of coil parameters on the characteristics of argon discharges in 2D axi-symmetric inductively coupled plasma (ICP) torch working at atmospheric pressure. Simulations were carried out using an indigenously developed CFD code in FORTRAN for ICP torch. The code uses the standard RF-ICP torch geometry to solve continuity, momentum, energy and vector potential equations under the assumption of LTE, steady and laminar flow. Using ICP torch argon plasma is simulated at oscillator frequency of 3.0 MHz with coil current 152 Amp. The coil parameters such as number of turns of the coil (N c ), spacing between the turns of the coil (L c ), radius of coil turn (R c ), axial variation of first coil position (P c ) and non uniform spacing of the coil turn, are varied to study their effect on temperature and flow fields in ICP torch. The results indicate that increase in number of turns of the coil increase total power dissipated into discharge almost linearly. The spacing between turns of the coil drastically affects the flow pattern and the total power dissipated into discharge. Increase in radius of the coil turn decreases the maximum energy dissipation rate and hence affects the temperature field. The axial variation of coil position affects the flow field .Wall temperature profile plays an important role in deciding the practical suitability of a particular coil configuration. It has been shown that temperature and flow fields can be controlled by changing various coil parameters and one can design an ICP torch system suitable for a particular process application.
IntroductionIn 1961, Reed [1] reported first time that a stable atmospheric pressure discharge can be produced by inductively heating a gas with RF power sources. Since past four decades RF (radio frequency) ICP (Inductively coupled plasma) system has been subject of interest for both industrial applications and basic understanding of plasma discharge. The main advantages of ICP are that it is electrodeless which helps in obtaining contamination free plasmas, have low flow velocity and large volume of plasma. Due to this it has wide range of industrial applications in powder spheroidization, spectrochemical analysis, sintering, spray coating of ceramic and metallic powders, synthesis of ultra fine powders of advanced materials, nano particle synthesis, etc.To calculate the flow and temperature fields in inductively coupled plasma mathematical modeling has made considerable advances. Various models have been developed in last three decades such as one dimensional model [2][3][4], two dimensional model with 1D electromagnetic equation [5][6][7][8], twodimensional vector potential model [9]. A comprehensive review on 2D modeling of inductively coupled plasma has been published in year 1992 by Mostaghimi and Boulos [10]. Progress in