Modeling the effects of concentration of solid nanoparticles in liquid feedstock injection on high-velocity suspension flame spray process

摘要

This paper presents the effects of the concentration of solid nanoparticles in the liquid feedstock injection on thehigh-velocity suspension flame spray (HVSFS) process. Four different concentrations of solid nanoparticles in suspensiondroplets with various droplet diameters are used to study gas dynamics, vaporization rate, and secondary breakup. Two types ofinjections, viz. surface and group, are used. The group-type injection increases the efficiency of droplet disintegration and theevaporation process and reduces the gas cooling. The initiation of the fragmentation process is difficult for small droplets carryinga high concentration of nanoparticles. Also, smaller droplets undergo rapid vaporization, leaving clogs of nanoparticles in themiddle of the barrel. For larger droplets, severe fragmentation occurs inside the combustion chamber. For a higher concentrationof nanoparticles, droplets exit the gun without complete evaporation. The results suggest that, in coating applications involving ahigher concentration of nanoparticles, smaller droplet sizes are preferred.