Surface heat and flow control for enhanced drying of porous media
- 발행기관 서강대학교 일반대학원
- 지도교수 Gihun Son
- 발행년도 2026
- 학위수여년월 2026. 2
- 학위명 박사
- 학과 및 전공 일반대학원 기계공학과
- 실제URI http://www.dcollection.net/handler/sogang/000000082473
- UCI I804:11029-000000082473
- 본문언어 영어
- 저작권 논문은 저작권에 의해 보호받습니다.
초록(요약문)
Many industrial products require drying processes and are composed of porous media, which makes moisture removal inherently difficult. To achieve rapid liquid removal from porous media, drying technologies based on convective and conductive heat transfer are commonly employed. Improving drying performance in manufacturing requires both reducing energy consumption and preventing product deformation to ensure product quality, both of which are governed by heat transfer and fluid flow within porous media. However, effectively improving drying performance remains challenging due to the inherent difficulty of controlling heat and fluid flow in complex porous media with micro- to nanoscale pore structures, where phase change and two-phase flow occur simultaneously. Therefore, this thesis aims to improve drying performance by controlling heat and fluid flow in porous media. Specifically, it focuses on heat transfer and fluid flow at surfaces in contact with heat sources, where phase change occurs dominantly. By identifying the key factors governing heat and fluid flow in porous media, this thesis proposes simple yet innovative strategies for effectively enhancing drying performance. In Chapter 2, we investigate the effect of interfacial thermal contact conductance on the drying rate at the contact surface between a heat source and a porous medium during conductive drying. Thermal contact conductance is governed by the actual contact area, which varies with the contact pressure between the two bodies and has a dominant influence on the heat flux transferred to the liquid. Accordingly, the results demonstrate that the drying rate can be enhanced by appropriately adjusting the contact pressure. In Chapter 3, we investigate the effect of surface pore size on the drying rate during convective drying, with a focus on the interface where hot air comes into contact with porous media. Surface pore size governs liquid transport and surface liquid saturation through the interplay of capillary and viscous effects. Because these factors directly influence the effective contact area between hot air and liquid, the results demonstrate that the drying rate can be enhanced by appropriately controlling the surface pore size. In Chapter 4, we investigate the effect of liquid viscosity on particle distribution after drying of a polydisperse colloidal suspension. The analysis reveals that liquid flow toward the evaporating interface, which is pinned at the surface exposed to hot air during drying, transports and accumulates particles. The behavior of this evaporating interface is governed by the balance between capillary and viscous forces. Because liquid viscosity directly controls the viscous force, the results demonstrate that adjusting viscosity can suppress interfacial pinning and thereby achieve a more uniform particle distribution after drying.
more목차
Abstract vii
1. Background 1
2. Dependence of drying rate on interfacial thermal contact conductance in drum drying of
thin porous media 6
3. Enhancing drying efficiency of porous media by controlling surface pore size in
convective drying 37
4. Viscosity-controlled particle distribution in convective drying of polydisperse colloidal
suspensions 64
5. Conclusion 89
References 92
