LEIDENFROST PHENOMENON - FILM BOILING OF LIQUID DROPLETS ON A FLAT PLATE
LEIDENFROST PHENOMENON - FILM BOILING OF LIQUID DROPLETS ON A FLAT PLATE
复制标题
DOI：
10.1016/0017-9310(66)90112-8
复制
发表时间：
1966-01-01
影响因子：
5.2
通讯作者：
BELL, KJ
中科院分区：
文献类型：
--
作者：
GOTTFRIED, BS;LEE, CJ;BELL, KJ
小液滴在大气中热的平面上的薄膜沸腾通常被称为莱顿弗罗斯特现象。Leidenfrost于1756年首次研究了这一过程。在本研究中，测定了水、四氯化碳、乙醇、苯和正辛烷的小液滴（< 0.1 ml）在不锈钢板上的总蒸发时间，表面温度为150°C至500°C。大多数数据是在膜沸腾状态下获得的，但也在核态和过渡态沸腾状态下获得数据。测定莱顿弗罗斯特点，其定义为液滴蒸发时间最大时的板温度。莱顿弗罗斯特点被发现是100-105摄氏度以上的饱和温度为所有液体，水除外，莱顿弗罗斯特点的精确值似乎取决于表面和沉积液滴的方法，并从150摄氏度到210摄氏度以上的饱和度。Leidenfrost点是独立的液滴尺寸在整个范围内studied.A分析模型的Leidenfrost现象的假设：热传递到液滴通过传导通过蒸汽膜上的下半部分和辐射到整个液滴。通过在下表面上蒸发以提供蒸汽膜以及通过从上表面扩散来从液滴去除质量。液滴由蒸汽膜中的过压支撑。假设液滴为球形，在饱和温度下等温。通过满足该模型的热量、质量和动量平衡，得到瞬时蒸发率;通过积分蒸发率计算总蒸发时间。计算和实验的蒸发时间同意在20%之内，除了forn-octane在高温下，在那里可能发生一些热裂解。
The film boiling of small droplets of liquid on a hot flat surface in the atmosphere is commonly termed the Leidenfrost Phenomenon after J. G. Leidenfrost who first studied the process in 1756.In the present study, the total evaporation times were determined for small droplets (< 0.1 ml) of water, carbon tetrachloride, ethanol, benzene, andn-octane on a stainless steel plate at surface temperatures ranging from 150°C to 500°C. Most of the data were taken in the film boiling regime though data were also taken in the nucleate and transition boiling regimes. The Leidenfrost point, defined as the plate temperature at which the droplet evaporation time is greatest, was determined. The Leidenfrost point was found to be 100–105 degC above the saturation temperature for all liquids except water; for water, the exact value of the Leidenfrost point appears to depend upon the surface and the method of depositing the droplet and varies from 150 degC to 210 degC above saturation. The Leidenfrost point is independent of droplet size over the range studied.An analytical model of the Leidenfrost phenomenon is postulated: Heat is transferred to the droplet by conduction through the vapor film on the bottom half and by radiation to the entire droplet. Mass is removed from the droplet by evaporation on the lower surface to supply the vapor film and by diffusion from the upper surface. The droplet is supported by the excess pressure in the vapor film. The droplet is presumed spherical and isothermal at the saturation temperature. The instantaneous evaporation rate is found by satisfying the heat, mass, and momentum balances for this model; total evaporation times are calculated by integrating the evaporation rate. Calculated and experimental evaporation times agree within 20 per cent except forn-octane at high temperatures, where some thermal cracking may have occurred.