| 引用本文: | 尚宇恒,侯予,白博峰,钟昕.壁面过冷度对液滴撞击动力学的影响[J].哈尔滨工业大学学报,2022,54(7):104.DOI:10.11918/202104085 |
| SHANG Yuheng,HOU Yu,BAI Bofeng,ZHONG Xin.Effect of surface subcooling on the droplet impacting dynamics[J].Journal of Harbin Institute of Technology,2022,54(7):104.DOI:10.11918/202104085 |
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| 摘要: |
| 为深入探究液滴撞击过冷壁面的动态特性以及不同参数对液滴铺展过程的影响,针对液滴撞击硅片的动态铺展行为进行了可视化实验研究,通过改变撞击速度以及液滴尺寸获得了大范围韦伯数下液滴铺展特性随壁面过冷度变化的普遍规律。结果表明,壁面过冷条件下,在不同韦伯数区域,液滴最大铺展直径随壁面温度的升高呈现不同的变化趋势。在低韦伯数区域（We<190）,由于液体黏性及表面张力降低,液滴最大铺展因子随着壁面过冷度的降低而增大；在高韦伯数区域（We>190）,液滴最大铺展因子随着壁面过冷度的降低呈现先下降后上升的趋势,该非线性趋势是壁面温度上升导致最大无量纲指状长度的减量与最大内部铺展因子的增量相互竞争的结果；韦伯数为209时,壁面温度从-36.6 ℃上升至-27.6 ℃,导致最大铺展因子降低5.9%；较大的韦伯数是液滴四周形成指状形态的前提,较低的壁面温度会加剧液膜减速从而强化该形态；液滴达到最大铺展直径的时间随着壁面温度的上升略有增加,随着液滴尺寸的增加显著增加,但几乎不随撞击速度发生变化。研究结果揭示了壁面过冷度对液滴撞击动力学的显著影响,可为控制固-液接触面积的新策略提供理论依据。 |
| 关键词: 液滴撞击 动态铺展 壁面过冷度 手指状形态 铺展因子 |
| DOI：10.11918/202104085 |
| 分类号:TK121 |
| 文献标识码:A |
| 基金项目:国家自然科学基金资助(51806163)； 结冰与防除冰重点实验室开放课题(IADL20190101)； 中央高校基本业务费(ND6J005,xjh012019017) |
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| Effect of surface subcooling on the droplet impacting dynamics |
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SHANG Yuheng,HOU Yu,BAI Bofeng,ZHONG Xin
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(School of Energy and Power Engineering, Xi′an Jiaotong University, Xi′an710049, China)
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| Abstract: |
| To study the dynamic characteristics of a droplet impact on a supercooled surface and the influence of different parameters on the spreading process of the droplet, the spreading behavior of a single water droplet impacting on a silicon surface has been experimentally investigated. Various impact velocities and droplet sizes are employed to enlarge the Weber number range. Results show that under the subcooling condition of the surface, the droplet spreading dynamics with the increasing of surface temperature exhibits a complex dependence on the Weber number. For a small Weber number (We<190), the maximum spreading factor shows a monotonic increase with the decreasing of surface subcooling due to a smaller liquid viscosity and surface tension. In the high Weber number region (We>190), the maximum spreading factor first decreases and then increases with the decreasing of surface subcooling. The non-monotonic relationship is ascribed to the competition between the decreased non-dimensional maximum fingering length and the increased maximum interior spreading factor with the increasing of surface temperature. In the case of We=209, the surface temperature increases from -36.6 ℃ to -27.6 ℃, resulting in 5.9% decrease of the maximum spreading factor. A relatively high Weber number leads to the formation of a fingering pattern, and a low surface temperature strengthens the phenomenon attributed to the enhanced deceleration of the liquid film. The moment at the maximum spreading diameter weakly increases with the surface temperature and strongly increases with the droplet size, while it barely increases with the impact velocity. |
| Key words: impact droplet spreading dynamics surface subcooling fingering pattern spreading factor |
