How ambient pressure influences water droplet nucleation at tropospheric conditions
How ambient pressure influences water droplet nucleation at tropospheric conditions
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环境压力如何影响对流层条件下的水滴成核
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
H. Lihavainen
中科院分区：
文献类型：
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作者：
A. Hyvärinen;D. Brus;J. Wedekind;H. Lihavainen
尽管有越来越多的实验证据，但成核理论通常忽略环境压力对过饱和蒸汽中液滴凝结的影响。我们已经应用了最近提出的模型，将这种效果的水在对流层条件下的均匀成核率。我们用层流扩散室测量了低到中压（70 - 200 kPa）和240 - 270 K温度下氦中水的压力相关成核速率。所观察到的压力效应在270 K下显示出明显的正效应（随着压力的增加成核速率增加），并且在较低温度下显示出较弱的效应，与理论一致。实验的压力效应比理论预测的更明显。压力效应的相同原理也适用于水的非均质成核，这意味着在对流层条件下，通过水的液滴成核去除水蒸气可能会受到抑制。
Nucleation theories typically neglect the influence of the ambient pressure on the condensation of droplets from a supersaturated vapor, despite increasing experimental evidence. We have applied a recently presented model that incorporates this effect to the homogeneous nucleation rates of water at tropospheric conditions. We measured experimental pressure dependent nucleation rates of water in helium at low to intermediate pressures (70–200 kPa) and at temperatures from 240–270 K with the laminar flow diffusion chamber. The observed pressure effect shows a clear positive effect (increasing nucleation rate with increasing pressure) at 270 K and a weaker effect with lower temperatures, consistent with the theory. The experimental pressure effect was more pronounced than predicted by theory. The same principle of the pressure effect should also hold for heterogeneous nucleation of water, which implies that water vapor removal by droplet nucleation of water may be suppressed at tropospheric conditions.