Rapid Heating of Gas/Small Particle Mixture

Abstract

The concept of using a mixture of particles and air as a medium to absorb radiative energy has been proposed for various applications. In this paper, carbon particles mixed with gas form a medium that absorbs radiation from sources such as concentrated solar energy. A single-particle, two-temperature model is used to study the transient temperature of the particle/gas mixture as it undergoes a constant pressure expansion process. The results indicate that for particles smaller than 1 μm in diameter, the surrounding air can be heated as quickly as the particles, while for particles larger than 1 mm in diameter, the air temperature stays relatively unchanged and the particles are heated to a very high temperature. The scattering albedos from the particles are also calculated, revealing that their contribution from scattering to the heating process is insignificant for particles with diameter less than 1 μm.