转盘边缘黏性薄液膜不同破碎模式临界转变特性

发布时间：2018-03-27 16:03

本文选题：流体力学　切入点：模型　出处：《化工学报》2017年11期

【摘要】：液膜在离心粒化器边缘的破碎模式直接决定了雾化后的液滴形态和尺寸分布,是影响物料品质的关键因素。针对转盘粒化器,提出临界转变系数表征液膜由膜状向纤维状破碎的转变条件,并拓展至其他破碎模式,建立了滴状向纤维状、完全纤维状及纤维状向膜状破碎转变的临界关系。结果表明,转盘表面润湿性对于液膜呈滴状以及滴状向纤维状模式转变影响显著,未完全润湿导致临界流量存在一定的随机性,转盘直径与临界流量间无明确规律;而完全纤维状以及膜状时,大直径转盘临界流量明显升高。转速、流量、密度及黏度的提高,破碎模式趋向于膜状;而增大表面张力,即使对于较大流量和转速,液膜也能维持纤维状或滴状模式。调整转盘直径将引起表面张力与离心力同时变化,若未打破平衡,其破碎模式不会改变。研究结果为转盘粒化器的设计与优化提供了可借鉴的理论与应用基础。
[Abstract]:The breakup mode of liquid film on the edge of centrifugal granulator directly determines the droplet shape and size distribution after atomization, and is the key factor affecting material quality. The critical transition coefficient is proposed to characterize the transition condition of liquid film from film-like to filamentous breakage, and to extend to other crushing modes. The critical relationship between drip-like, completely fibrous and fibrous to film-like breakage is established. The wettability of the surface of the rotary disc has a significant effect on the liquid film droplet and the change from the dripping to the fibrous mode. The critical flow rate is random due to incomplete wetting, and there is no clear rule between the diameter of the disc and the critical flow rate. However, the critical flow rate of the large diameter turntable increases obviously when the filamentous and filamentous. The breaking mode tends to film with the increase of rotational speed, flow rate, density and viscosity, and increases the surface tension, even for the larger flow rate and rotational speed, The liquid film can also maintain a fibrous or dripping pattern. Adjusting the diameter of the turntable will cause both surface tension and centrifugal force to change simultaneously, if the balance is not broken, The results provide a theoretical and practical basis for the design and optimization of the rotary disc granulator.
【作者单位】：江南大学机械工程学院江苏省食品先进制造装备技术重点实验室;南京工业大学江苏省过程强化与新能源装备技术重点实验室;
【基金】：国家自然科学基金项目(51606086,51406078)~~
【分类号】：TQ021.1

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