TRANSIENT RADIATIVE HEAT TRANSFER WITHIN A PARTICLE SUSPENSION UNDERGOING ENDOTHERMAL DECOMPOSITION - SHRINKING VS. NON-SHRINKING PARTICLES

DOI: 10.1615/ICHMT.2004.RAD-4.300
10 pages

Wojciech Lipinski
Research School of Engineering, The Australian National University, Canberra ACT 2601, Australia

Aldo Steinfeld
Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland; Solar Technology Laboratory, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland

Resumo

A transient model coupling radiative transfer to chemical kinetics is examined for a non-isothermal, non-gray, absorbing, emitting, and Mie-scattering suspension of chemical reacting particles that are exposed to an external source of concentrated thermal radiation and undergo endothermic decomposition. The Monte Carlo and finite volume methods are applied for solving the mass and energy conservation equations. Two cases are considered: non-shrinking and shrinking particles. In the former case, radiation absorption is superior, resulting in a faster reaction rate. In the latter case, the radiative properties vary strongly with time as the reaction progresses. The reaction rate is slower because of the less efficient absorption as the size parameter decreases and the medium becomes optically thinner. Both cases are compared in terms of their temperature profiles and reaction extents.