Experiments on adding a surfactant to water drops boiling on a hot surface
Experiments on adding a surfactant to water drops boiling on a hot surface
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DOI：
10.1098/rspa.1997.0038
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发表时间：
1997-04
期刊：
影响因子：
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通讯作者：
Y. Qiao;S. Chandra
中科院分区：
文献类型：
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作者：
Y. Qiao;S. Chandra
研究了添加表面活性剂十二烷基硫酸钠对不锈钢表面液滴沸腾的影响。使用含有100 ppm和1000 ppm（重量）表面活性剂的溶液进行实验，并将结果与纯水液滴的结果进行比较。表面温度从60到340摄氏度变化。使用视频和35 mm摄像机拍摄液滴撞击和蒸发。添加的表面活性剂显着减少了蒸发或核态沸腾状态下的液滴的寿命。对于低于引发核态沸腾所需的表面温度，表面活性剂的主要作用是减少液-固接触角，增加由液滴润湿的表面积。在较高的表面温度下，表面活性剂促进液体中的汽泡成核和发泡，大大增强了传热。表面活性剂浓度的增加降低了莱顿弗罗斯特温度，高于该温度，液滴在其自身蒸汽的薄膜上悬浮在表面上方。表面活性剂对液滴蒸发时间没有影响。
The effect of adding a surfactant (sodium dodecyl sulphate) to droplets boiling on a hot stainless steel surface was studied. Experiments were done using solutions containing 100 ppm and 1000 ppm by weight of surfactant and the results compared with those for droplets of pure water. Surface temperature was varied from 60 to 340 degrees C. Droplet impact and evaporation was photographed using both video and 35 mm cameras. Addition of the surfactant significantly reduced lifetimes of droplets in a state of evaporation or nucleate boiling. For surface temperatures below those required to initiate nucleate boiling, the principal effect of the surfactant was to reduce liquid–solid contact angle, increasing the surface area wetted by the drop. At higher surface temperatures, the surfactant promoted vapour bubble nucleation and foaming in the liquid, greatly enhancing heat transfer. Increasing surfactant concentration reduced the Leidenfrost temperature, above which droplets were levitated above the surface on a thin film of their own vapour. The surfactant had no effect on evaporation time of droplets in film boiling.