Drying of a Fully Saturated Porous Medium With Excess Water Layers: A Numerical Study
Drying of a Fully Saturated Porous Medium With Excess Water Layers: A Numerical Study
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具有过量水层的完全饱和多孔介质的干燥：数值研究
DOI：
10.1115/1.4056068
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Yagoobi, Jamal
中科院分区：
文献类型：
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作者：
Asar, Munevver Elif;Yagoobi, Jamal
潮湿多孔介质的干燥能源效率非常低。例如，在纸浆和造纸工业中，纸张干燥消耗的能量占造纸机总能耗的三分之二以上。新型干燥技术可以减少干燥所用的能源，并减少制造过程的碳足迹。开发下一代干燥技术来干燥潮湿的多孔介质可能需要了解如何用过量的水从完全饱和的多孔材料中去除水分。本文提供了对具有过量水的完全饱和多孔介质中的传热和传质的基本理解。例如，这与出于隔热目的而干燥薄纸以及纸浆或纸张有关，其中优选避免压制以克服片材厚度的减小。为此，开发了一个理论干燥模型，其中多孔介质对应于纸张，并假设夹在两个过量水层（底部和顶部）之间。共轭模型由每层的能量和质量守恒方程组成。并用相应的实验数据对模型进行了验证。在该模型中，每个水层的厚度根据当地温度和总含水量计算为干燥时间的函数。数值模型在空间中（即厚度方向）是瞬态的、一维的。本文演示了从一侧加热具有水层的饱和多孔介质时的控制方程、边界条件和结果。当多孔介质干燥时，在其厚度方向上估计湿度和温度分布。
Drying of moist porous media can be very energy inefficient. For example, in the pulp and paper industry, paper drying consumes more than two-thirds of the total energy used in paper machines. Novel drying technologies can decrease the energy used for drying and lessen the manufacturing processes' carbon footprint. Developing next-generation drying technologies to dry moist porous media may require an understanding of removing moisture from a fully saturated porous material with excess water. This paper provides a fundamental understanding of heat and mass transfer in a fully saturated porous medium with excess water. This is relevant, for example, in drying tissue as well as pulp or paper for the purpose of thermal insulation where pressing is preferred to be avoided to overcome the reduction in the sheet thickness. For this purpose, a theoretical drying model is developed where the porous medium corresponds to paper and is assumed to be sandwiched between two excess-water layers (bottom and top). The conjugate model consists of energy and mass conservation equations for each layer. The model is validated with corresponding experimental data. In the model, the thickness of each water layer is calculated as a function of drying time based on local temperature and total moisture content. The numerical model is transient and one-dimensional in space (i.e., in the thickness direction). This paper demonstrates the governing equations, boundary conditions, and results when the saturated porous medium with water layers is heated from one side. Moisture and temperature profiles are estimated in the thickness direction of the porous medium as it dries.