Abstract:
During slurry breakup, the throat of the liquid bridge keeps shrinking. When the minimum characteristic diameter of the liquid bridge is close to the size of the solid particle, the slurry will exhibit complex variation characteristics with time, which is significantly different from those of pure liquid. Therefore, scrutinizing the micro breakup characteristics of slurry will help reveal the atomization mechanism and improve the modeling of slurry. Here, Shenhua and Huadian coals are used as raw material to prepare coal water slurry in a mass fraction range of 58%—62%. The influence of the physical and chemical parameters of coal water slurry on its microscopic breakup processes is studied by rotary rheometer, static surface tension meter, dynamic surface tension meter, high-speed camera and image processing software. Considering that coal water slurry is a shear thinning non-Newtonian fluid, the Herschel-Bulkley model is used to establish the rheological relationship of coal water slurry. Unlike static surface tension, the dynamic surface tension of coal water slurry decreases with the increase of the characteristic bubble time. The minimum surface tension is achieved about 200 ms. Finally, based on the rheological properties and the dynamic surface tension of coal water slurry, the relationship between the characteristic diameter changes of coal water slurry micro-breakup and the breakup time is obtained.