Effects of swirling flow on ultralight particle dispersion characteristics in coaxial jet combustor

Abstract

The dispersion characteristics of ultralight particle (expanded graphite) in swirling mixture particle-laden coaxial jet combustor was modeled and numerically predicted using developed second-order moment gas-particle multifluid turbulent model. An improved gas-particle and particle-particle Reynolds stress transport to describe its anisotropic behaviors was proposed. Experimental validation for single-phase particle flow has been conducted with satisfied agreement. The multifluid hydrodynamic parameters, that is, number density, particle velocity, fluctuation velocity, Reynolds stress correlation of gas-particle and particle-particles, and effects of swirling number are investigated. The results found that the ultralight particles exhibited the distinctive anisotropic behaviors, and their unique flow structures were quite different from those of heavier particles. Under the strong swirling flow condition, the anisotropic dispersions were enhanced and concentration at recirculation regions increased. The axial velocities and fluctuations, and the axial-axial and tangential-tangential stress correlations of gas-particles were weakened. The effect of swirling strength on ultralight particle dispersions is more sensitive in comparison with heavier particle.