Thermophoretic interaction of heat releasing particles

This study investigates thermophoretic force acting at heat releasing (absorbing) particles near the interface between two media with different thermal conductivities. This force is caused by the induced temperature gradient which is proportional to the rate of heat release (absorption) by the particle. Therefore the magnitude of the thermophoretic force is proportional to the rate of heat release (absorption) by the particle, and its direction depends upon the sign of the parameter kappa(1)-kappa(2), where kappa(1) is thermal conductivity of a host medium and kappa(2) is thermal conductivity of the adjacent medium. The obtained results imply that a heat releasing (absorbing) particle is attracted (repelled) to the interface when thermal conductivity of a host medium is less than thermal conductivity of the adjacent medium. Thus, e.g., growing in air by condensation particle is attracted to a metal surface while an evaporating in air particle is repelled from a metal surface. The change of temperature distribution caused by heat releasing particles results in the additional thermophoretic interaction of these particles. We determined a condition for mutual attraction of two spherical heat releasing particles and derived an expression for the thermophoretic force acting at the particles. The magnitudes of the considered thermophoretic forces are compared with the classic thermophoretic force. (C) 2003 American Institute of Physics.