The article deals with the electromagnetic radiation transfer in systems of spherical disperse particles with different optical characteristics. A model of the electromagnetic radiation transfer in cylindrical particles containing a small volume of different chemical substance is developed. The substance differs substantially from that of the particle in a radiation absorption coefficient for the wavelength under study in the long wave approximation. The finite element method is used to calculate the temperature field for the system of spherical particles in a two-dimensional approximation. The configurations of particle packing is chosen on a random basis, which significantly complicated the calculations, the longitudinal and transverse diameters of particle clusters, the distance between centers of two largest particles, and similar natural geometric properties have been considered as characteristic system dimensions.The possibility of controlling heat transfer in such systems is studied. It follows from our model calculations that both electromagnetic and thermal interaction of dispersed particles can be noticeable at large distances between their centers; that near the boundary of the dispersed particle there is a thermal surface layer of the particle, where the temperature distribution is essentially heterogeneous. It is concluded that the thermal mechanism of destruction of a weakly absorbing particle due to a strong increase in temperature because of electromagnetic resonance in a neighboring particle with a strong absorption. It is established that the effect of collective influences in polydisperse system can change temperature by more than 1,5 times.
Pressure-drop-fluid-flow correlation for fixed beds of small, irregularly shaped particles
