Moisture movement in porous materials under temperature gradients
Moisture movement in porous materials under temperature gradients
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DOI：
10.1029/tr038i002p00222
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发表时间：
1957-04
期刊：
影响因子：
--
通讯作者：
J. R. Philip;D. D. Vries-D.
中科院分区：
文献类型：
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作者：
J. R. Philip;D. D. Vries-D.
发展了温度梯度下多孔材料中水分运动的理论，该理论解释了明显不一致的实验信息，包括（a）表观蒸汽传递的大值，（b）水分含量对净水分传递的影响，以及（c）通过蒸馏传递潜热。先前关于温度梯度下多孔介质中水蒸气扩散的简单理论忽略了汽、液、固相的相互作用，以及充满空气的孔隙和整个土壤的平均温度梯度之间的差异。考虑到这些因素，开发了一种（公认的近似）分析，该分析预测了数量级和一般行为，与实验事实令人满意地一致。本方法的一个重要含义是，用于区分液体和蒸汽传输的实验方法尚未做到这一点，因为被认为是蒸汽传输的实际上是通过位于蒸汽连续体中的液体“岛”的串并联流。建立了描述在湿度和温度梯度组合下多孔材料中的湿度和热传递的方程。简要讨论了与此相关的四种与湿度相关的扩散系数。
A theory of moisture movement in porous, materials under temperature gradients is developed which explains apparently discordant experimental information, including (a) the large value of the apparent vapor transfer, (b) effect of moisture content on net moisture transfer, and (c) the transfer of latent heat by distillation. The previous simple theory of water vapor diffusion in porous media under temperature gradients neglected the interaction of vapor, liquid and solid phases, and the difference between average temperature gradient in the air-filled pores and in the soil as a whole. With these factors taken into account, an (admittedly approximate) analysis is developed which predicts orders of magnitude and general behavior in satisfactory agreement with the experimental facts. An important implication of the present approach is that experimental methods used to distinguish between liquid and vapor transfer have not done so, since what has been supposed to be vapor transfer has actually been series-parallel flow through liquid ‘islands’ located in a vapor continuum. Equations describing moisture and heat transfer in porous materials under combined moisture and temperature gradients are developed. Four moisture-dependent diffusivities arising in this connection are discussed briefly.