《厦门大学学报（自然科学版）》

正庚烷-丙酮二元混合物在蒸发过程中由于蒸发热效应,导致界面温度下降,可引发Marangoni对流.通过点光源投影法观察Marangoni对流在此二元混合物蒸发过程中的演变过程,并结合流体体积模型和连续表面张力模型,对此传质过程中出现的Marangoni对流进行了数值计算,获取了速度场、浓度场及温度场信息,以及Marangoni对流对传质产生显著影响的起始时间.结果表明,传质过程伴随的热效应可引发Marangoni对流,并对传质有着重要影响.

The Marangoni convection can be induced by decrease in the gas-liquid interface temperature due to the thermal effect accompanying in the evaporation of the n-heptane-acetone binary mixture.The development and evolution of the Marangoni convection during the evaporation process of the n-heptane-acetone binary mixture were observed directly with the optical shadowgraph method.A transient numerical computation was developed and conducted through combining the volume of fluid numerical method with the continuum surface tension method.The details of local velocity field,temperature and concentration distribution of the Marangoni convection were revealed by means of the simulation,and the reference time when the Marangoni convection took effect to enhance the mass transfer coefficient was acquired.It was found that the thermal effect associated with the mass transfer could play an important role in inducing the Marangoni convection and influencing mass transfer.

引言
1 实验
2 数值计算模型
3 结果及分析
4 结论

表1 20 ℃下溶剂的物理性质<br/>Tab.1 Physical properties of solvents at 20 ℃

表1 20 ℃下溶剂的物理性质
Tab.1 Physical properties of solvents at 20 ℃

图1 投影法示意图<br/>Fig.1 Sketch of the shadowgraph optical observation

图1 投影法示意图
Fig.1 Sketch of the shadowgraph optical observation

图2 测试盒结构<br/>Fig.2 Structure of the test box

图2 测试盒结构
Fig.2 Structure of the test box

图3 正庚烷-丙酮溶液蒸发过程中随时间变化的投影图像<br/>Fig.3 Transient shadowgraphs during evaporation of n-heptane-acetone solution

图3 正庚烷-丙酮溶液蒸发过程中随时间变化的投影图像
Fig.3 Transient shadowgraphs during evaporation of n-heptane-acetone solution

图4 计算区域示意图<br/>Fig.4 Schematic of computational domain

图4 计算区域示意图
Fig.4 Schematic of computational domain

$图5 随时间变化的流函数图(左)和丙酮摩尔分数分布图(右)<br/>Fig.5 Streamlines(left)and contours of acetone mole fraction(right)with respect to ime$

图5 随时间变化的流函数图(左)和丙酮摩尔分数分布图(右)
Fig.5 Streamlines(left)and contours of acetone mole fraction(right)with respect to ime

$图6 界面平均丙酮摩尔分数随时间变化曲线<br/>Fig.6 Curve of average acetone mole fraction at the interface with respect to time$

图6 界面平均丙酮摩尔分数随时间变化曲线
Fig.6 Curve of average acetone mole fraction at the interface with respect to time

图7 液相平均传质系数随时间变化曲线<br/>Fig.7 Curve of average mass transfer coefficient of the liquid phase with respect to time

图7 液相平均传质系数随时间变化曲线
Fig.7 Curve of average mass transfer coefficient of the liquid phase with respect to time

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备注

引言

1 实验

2 数值计算模型

3 结果及分析

4 结论

学报简介

备注

引言

1 实 验

2 数值计算模型

3 结果及分析

4 结 论

学报简介

1 实验

4 结论