ARTICLE:

• TEMPERATURE AND THERMAL STRESS PROFILES IN SEMI-TRANSPARENT PARTICLES HEATED BY CONCENTRATED SOLAR RADIATION  download article

Leonid A. Dombrovsky
1 Joint Institute for High Temperatures, Krasnokazarmennaya 17A, 111116, Moscow, Russia

Wojciech Lipinski
ETH - Swiss Federal Institute of Technology Zurich, Zurich, Switzerland

ABSTRACT

Transient temperature and thermal stress profiles in semi-transparent spherical particles heated by concentrated solar radiation are studied by means of a theoretical model. The analysis of radiative-conductive interaction is based on the spectral radiation transfer model in a refracting and absorbing particle. The stress-strain state of the particle is described by the thermoelastic approach. An analytical self-similar solution for the particle temperature profiles and thermal stresses during the quasi-steady period of the particle heating is derived. It is shown that the circumferential tensile stress near the particle surface is a non-monotonic function of the particle radius. The range of physical parameters corresponding to the maximal tensile stress near the particle surface is determined. The model is applied to ZnO and CaCO₃ particles, which are used as reactants in industrially-relevant high-temperature processes. It is shown that tensile stresses in the selected types of particles exposed to concentrated solar irradiation cannot lead to their mechanical destruction. At the same time, the considerable temperature difference and thermal stresses in non-isothermal particles may be an interesting issue in a detailed analysis of the thermal decomposition of the semi-transparent particle material.

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