Lukyanov Alex V, Mitkin Vladimir V, Pryer Tristan, Sirimark Penpark, Theofanous Theo G
School of Mathematical and Physical Sciences, University of Reading, Reading RG6 6AX, UK.
P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow 119991, Russia.
Proc Math Phys Eng Sci. 2020 Dec;476(2244):20200488. doi: 10.1098/rspa.2020.0488. Epub 2020 Dec 23.
The problem of capillary transport in fibrous porous materials at low levels of liquid saturation has been addressed. It has been demonstrated that the process of liquid spreading in this type of porous material at low saturation can be described macroscopically by a similar super-fast, nonlinear diffusion model to that which had been previously identified in experiments and simulations in particulate porous media. The macroscopic diffusion model has been underpinned by simulations using a microscopic network model. The theoretical results have been qualitatively compared with available experimental observations within the witness card technique using persistent liquids. The long-term evolution of the wetting spots was found to be truly universal and fully in line with the mathematical model developed. The result has important repercussions for the witness card technique used in field measurements of the dissemination of various low-volatility agents in imposing severe restrictions on collection and measurement times.
低液体饱和度下纤维多孔材料中的毛细管传输问题已得到解决。研究表明，在低饱和度下，此类多孔材料中液体的铺展过程在宏观上可以用一个与先前在颗粒多孔介质实验和模拟中确定的类似的超快速非线性扩散模型来描述。宏观扩散模型得到了使用微观网络模型的模拟的支持。理论结果已与使用持久性液体的见证卡技术中的现有实验观察结果进行了定性比较。发现润湿斑的长期演变具有真正的普遍性，并且与所开发的数学模型完全一致。该结果对见证卡技术在各种低挥发性制剂传播的现场测量中的应用具有重要影响，对采集和测量时间施加了严格限制。
