Heat transfer of multiple impinging jets with gas–solid suspensions

Abstract

The heat transfer mechanism of multiple impinging jets with gas–solid suspensions has been investigated experimentally and numerically. By heat transfer experiments, the effects of nozzle Reynolds number, solid loading ratio, distance from jet exit to impingement surface, spacing between jets and solid particle characteristics on the heat transfer coefficient were cleared. In the case of using graphite particles, the heat transfer coefficient enhancement as against single phase flow are found all over the heat transfer surface. While, in the case of using glass beads particles, the heat transfer coefficient is decreased compared with single phase flow. Numerical simulation were also performed by using Yokomine et al.'s model in which both turbulence augmentation and suppression due to particles can be taken into account. In the case of graphite particle, particles flow near the heat transfer surface with making belt-shaped dense region after impingement and its heat capacity and function of turbulence augmentation are used effectively. When the glass beads are used, particles are scattered after impingement and turbulent kinetic energy near the heat transfer surface is decreased.