Experimental investigation of mixtures and foreign inclusions in water droplets influence on integral characteristics of their evaporation during motion through high-temperature gas area

Abstract

Experimental investigation of influence of mixtures and foreign inclusions in water droplets on integral characteristics of their evaporation during the motion through high-temperature (more than 1000 K) gas area has been held. Investigations have been conducted with the usage of two-phase and heterogeneous mixtures diagnostics optical methods “Particle Image Velocimetry” and “Interferometric Particle Imaging”. It has been established that salt admixtures injection with sufficiently large relative concentration (γ = 0.1) influences moderately on droplet evaporation characteristics (evaporation velocities are decreased by 5–7%) when water droplet sizes are less than 0.5 mm. Salt admixtures influence is intensified (evaporation mass velocities of water droplets with admixtures and without of them differ by 11–18% at droplet sizes 1–3 mm) with droplet size increase. It has been indicated that foreign solid particle injection in droplets leads to considerable (by several times) intensification of droplet heat-up and evaporation processes. The thermophysical characteristics of these foreign solid particles significantly differ from water. Conditions of significant deformation and breakage of water droplets with solid inclusions have been indicated at intensive evaporation.