Regular Article

Thermal study of the atomic ratio effect on a cylindrical and an ellipsoidal shaped HgTlI discharge lamps

¹ Research Unit of Ionized Backgrounds and Reagents Studies (UEMIR), Preparatory Institute for Engineering Studies of Monastir (IPEIM), University of Monastir, 5019 Kairouan Street, Monastir, Tunisia
² College of Engineering, Chemical Engineering Department, Hail University, Hail City, Saudi Arabia

^a e-mail: besmaferjani@gmail.com

Received: 22 January 2019
Revised: 12 June 2019
Published online: 24 September 2019

Abstract

The purpose of this paper is to study the thermal behavior of a high-intensity HgTlI lamp in a cylindrical shape, compared to an ellipsoidal lamp during variations of the mercury to thallium atomic ratio. For this, we developed a chemical model under Local Thermodynamic Equilibrium conditions. Then, it was coupled with a three-dimensional code, time-dependent that solves the systems of equations for the mass, energy and momentum, as well as the equation of Laplace for the plasma using Comsol Multiphysics coupled with Matlab. Based on the variations of the mercury to thallium ratio, we analyzed the temperature fields, the heat conduction flow, the convective flow and the accumulation of mercury behind the electrodes for both of the shapes in different mercury to thallium ratios.