화학공학소재연구정보센터
Atomization and Sprays, Vol.31, No.6, 23-43, 2021
TOWARD ATOMIZATION FOR GREEN ENERGY: VISCOUS SLURRY CORE DISRUPTION BY FEED INVERSION
A common method for maximizing energy utilization is to introduce organic particulate wastes (industrial, municipal, or sewer) into energy-harvesting equipment, such as steam boilers. Doing so, however, often requires the waste to be provided as a viscous slurry, which is difficult to disintegrate for combustion or gasification. Steam-assisted atomization is a usual solution, but supplemental steam reduces boiler efficiency. Minimizing steam introduction thus becomes a primary motivation. Typical twin-fluid atomizers involve steam flowing on the outside of the slurry; it is shown that this method produces unsatisfactory atomization at preferably low steam flows. Inverting the feeds, such that the slurry is outside the steam, changes the atomization behavior from slurry core-focusing to core-erupting and produces atomized slurry down to very low steam flows. The key is to allow interfacial unsteadiness to encourage a pulsing flow, which amplifies the growth of instabilities. Nozzle geometry evaluations, which involved balancing annular slurry sheet thickness against increased steam momentum, revealed that increasing the slurry sheet thickness reduced slurry pressure drop, increased droplet size, and dramatically increased temporal variability of the atomization process. Finally, a "forced interaction design" is proposed to more readily transmit motive fluid forces through the slurry sheet to improve atomization efficacy.