Influence of Poly (Ethylene Glycol) 20,000 Concentration on Atomization and Deposition Characteristics of Nozzle

The addition of surfactants to pesticide spray applications is an important method to improve the spray atomization and the coverage of droplets on the target. The effects of different types of surfactants on spraying have been extensively studied, but there have been few studies on the commonly used surfactant polyethylene glycol so far. This article compares the effect of polyethylene glycol 20,000 on the atomization and deposition characteristics by measuring the droplet size and the deposition on the polyethylene collection line when spraying different concentrations of polyethylene glycol 20,000 solution. The results show that the volume medium diameter DV0.5 of spraying different concentrations of polyethylene glycol 20,000 solution is larger than that of clear water, and that as the concentration increases, the volume medium diameter DV0.5 gradually increases but ΦVol < 150 μm decreases. Spraying different concentrations of polyethylene glycol 20,000 solution at a horizontal distance of 2–7 m from the nozzle and at a distance of 0.1–0.2 m from the bottom of the floor, the depositions are all less than that of clear water, and as the concentration increases, the deposition becomes smaller. This article can provide theoretical support for the use and concentration ratio of polyethylene glycol 20,000 in field application.

Spray atomization simulation of bamboo kraft black liquor with high solid content at splash-plate nozzle

Increasing the solids content of pulping black liquor burned in a furnace is a development trend of the alkali recovery system in the pulp and paper industry. However, the viscosity of kraft black liquor increases exponentially with an increase in solids content, especially in the case of non-wood pulping black liquor, such as bamboo. This brings great difficulties to the pulping system and atomization of black liquor at the splash-plate nozzle, which is a complete atomization unit constituted of a splash nozzle and a splash plate. To obtain instructive results for industry, a simulation of the atomization process was made using Fluent software for the bamboo kraft black liquor with solids contents of 70 wt% and 80 wt%, which flowed through splash nozzles with the diameter of 22 or 20 mm. The studies were conducted on the distribution of flow field in the nozzle and atomization region through changing the injection pressure and nozzle diameter. The variation of atomization characteristic parameters, such as liquid film thickness, and breakup length, were elucidated. The results reveal the relationship between spray atomization with injection pressure and nozzle diameter, which provides a theoretical basis for improving the concentration of black liquor entering alkali recovery in the future.