当前位置: X-MOL 学术Eur. J. Mech. B Fluids › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Thermo-hydrodynamic analysis of drop impact calcium alginate gelation process
European Journal of Mechanics - B/Fluids ( IF 2.5 ) Pub Date : 2020-12-28 , DOI: 10.1016/j.euromechflu.2020.12.012
Krishnayan Haldar , Sudipto Chakraborty

The phenomenon of calcium alginate gel formation from sodium alginate drop impact on calcium chloride liquid pool generates enormous scientific interest. The present work features on the investigation of interfacial heat transfer during sodium alginate drop impact on a heated calcium chloride liquid pool. The liquid pool has been heated at different temperatures varying from 20 °C to 70 °C. The drop chemically reacts at the interface and calcium alginate gel starts to form which has been instantaneously captured in a high-speed camera. A mathematical model on crater dynamics has been presented to determine the heat transfer coefficient and amount of interfacial heat transfer during the chemical reaction. Now, drop levitation over the vapour layer generated from the evaporation of liquid pool is defined as Leidenfrost pool Effect. This is characterized from the heat transfer at the crater initiation stage and accumulated vapour layer thickness, vapour pressure developed. The release of drop liquid is aided by the surface tension difference between drop and pool at the interface and it is defined as thermal Marangoni Effect. It has been characterized from the variation of Marangoni pressure with temperature which tends to drain away accumulated vapour layer. A critical liquid pool temperature has been obtained when Leidenfrost vapour pressure dominates over Marangoni pressure and resists the drop release during the gel initial regime. The dynamics of calcium alginate gelation is governed by intricate interplay between thermal Marangoni effect and Leidenfrost pool effect with its effect on initial gelation time and total gelation time.



中文翻译:

水滴撞击海藻酸钙凝胶化过程的热流体力学分析

海藻酸钠滴落形成的海藻酸钙凝胶现象对氯化钙液池的影响引起了极大的科学兴趣。目前的工作特点是研究海藻酸钠滴对加热的氯化钙液池的冲击过程中的界面传热。液体池已在20°C至70°C的不同温度下加热。液滴在界面处发生化学反应,海藻酸钙凝胶开始形成,并已在高速相机中即时捕获。提出了关于火山口动力学的数学模型,以确定化学反应过程中的传热系数和界面传热量。现在,由液池蒸发产生的蒸气层上的悬浮悬浮液定义为莱顿弗罗斯特池效应。其特征在于在火山口起始阶段的热传递和累积的蒸气层厚度,产生的蒸气压力。液滴在界面处的液滴与池之间的表面张力差有助于液滴的释放,这被定义为热马兰戈尼效应。它的特征是Marangoni压力随温度的变化而变化,这往往会流失积聚的蒸汽层。当莱顿弗罗斯特的蒸气压超过Marangoni的压力并在凝胶初始过程中抵抗液滴的释放时,已经获得了临界的液池温度。海藻酸钙凝胶化的动力学受Marangoni热效应和Leidenfrost池效应之间复杂相互作用的影响,该效应对初始胶凝时间和总胶凝时间有影响。

更新日期:2021-01-06
down
wechat
bug