Further development of temperature determination for a heated micron-sized particle from forced convection

A novel method for determining temperature of a micron-sized particle from forced convective force has been developed. The force was measured for a single suspended particle in an electrodynamic chamber. Particle heating was achieved by focused CO2 laser radiation. With negligible free convection, a correlation was formulated between the forced convective force and temperature-dependent viscosity of the gas, on the basis of the Stokes expression. According to this correlation, the ratio of hot to cold forced convective forces on a particle depends on the gas viscosity, and the particle temperature can be attained from this ratio. Particle temperature was determined for a non-reacting glassy carbon particle of 100 μm and a pyrolyzing polystyrene particle of 157 μm. It was shown that the developed method is straightforward and quite accurate with an uncertainty of less than 2.5%, and applicable to both reacting and non-reacting particles.