Abstract

The drying phenomena of an initially filled perfectly wetting liquid in a square internal cross-sectional tube are studied. The conditions are such that the liquid films develop along the tube internal corners under the effect of capillary forces until the bulk meniscus recedes in the tube. In this work, the Shan-Chen Lattice Boltzmann method (SC-LBM) is implemented to elucidate the complex multiphase phenomena involved in the isothermal drying of the square capillary tube. The SC-LBM is validated with Stefan-Maxwell diffusion relation and the simulated drying kinetics are in very good agreement with the commonly observed drying phenomena, which are the constant rate period (CRP) followed by the falling rate period (FRP). The computed capillarity along the liquid-gas interface at the internal corners of the tube results in the formation of extended corner films and surface films. Further, the pinning and the depinning phenomena as well as the variations of the corner film width are studied in detail. Based on the roughness factor of the tube, the characteristics of drying kinetics are studied and compared with the smooth square capillary tube.

摘要

研究了初始填充的完全润湿液体在方形内截面管中的干燥现象。条件是液体膜在毛细力的作用下沿管内角发展，直到管中的大弯月面后退。在这项工作中，采用 Shan-Chen 格子玻尔兹曼方法 (SC-LBM) 来阐明方形毛细管等温干燥过程中涉及的复杂多相现象。SC-LBM 用 Stefan-Maxwell 扩散关系进行验证，模拟的干燥动力学与常见的干燥现象非常吻合，即恒定速率期 (CRP) 和下降速率期 (FRP)。沿管内角处的液-气界面计算的毛细现象导致形成扩展的角膜和表面膜。此外，详细研究了钉扎和脱钉现象以及角膜宽度的变化。基于管子的粗糙度系数，研究了干燥动力学特性，并与光滑方形毛细管进行了比较。