Carmeliet

Contact

Jaebong Lee room HIL E 47.2
PhD student tel +41 58 765 4705
  fax +41 44 633 1041
  email lee@arch.ethz.ch

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Profile

Jaebong Lee has received his MSc Degree in Mechanical engineering in 2011, after the BSc degree in 2009 at the Chungang University (Seoul, South Korea). His MSc thesis was on "Dynamic wetting and spreading of a liquid droplet impinging on micro textured hydrophobic surfaces" at Multiscale Thermal Engineering Laboratory in Chungang University, supervised by Prof. Seong hyuk Lee. In spring 2012, he started his PhD project "Wetting of building facades by wind driven rain in the urban context" at ETH (Chair of Building physics, Department of Architecture) and EMPA(Building Science and Technology), supervised by Prof. Jan Carmeliet.

PhD project

Wetting of Building Facades by wind driven rain in the urban context

Wetting by wind-driven rain (WDR) refers to rain droplets carried by the wind and impinging on the building façade. WDR water is a main agent of deterioration of building materials, which becomes an important issue when retrofitting old or historical buildings by adding insulation, planning energy efficient cities, and doing assessment of soiling of facades and leaching of harmful biocides and nanoparticles from buildings. The understanding of phenomena of single water droplet, such as spreading, splashing, bouncing, absorption, evaporation, film forming and run-off can lead to better estimation of WDR load on buildings within urban environments.

To observe physics of impinging droplet on porous stones, high-speed imaging is used to capture short time phenomena (Fig. 1). Different outcomes of impinging droplet are observed by the size of pore and the porosity of stones. After droplet deposition on the stone, droplet imbibition into the stone is visualized by neutron radiography (Fig. 2). Numerical study for drop spreading and imbibition is planned in order to analyse pressure field and limitation of experimental case study. Numerical modelling for spreading of impinging droplet on impermeable substrate is validated with the literature (Fig. 3).

Figure 1. Time evolution of the water droplet of volume 4.3 μl spreading on a surface of porous stones(Vi = 1 m/s, RH 50 %).

Figure 2. Time evolution of imbibition of droplet by different impact speed of impinging droplet(Savonnieres, RH80%).

Figure 3. Validation of VOF modeling among (a) experiment, (b) previous model (S. Sikalo et al., 2005), and (c) current model of this study.


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Publications

Journal papers

  • C. Antonini, J. B. Lee, T. Maitra, S. Irvine, D. Derome, Manish K. Tiwari, J. Carmelie & D. Poulikakos . Unraveling wetting transition through surface textures with X-rays: Liquid meniscus penetration phenomena. Scientific Reports (2014).(DOI)
  • Joo Hyun Moon, Jae Bong Lee, Seong Hyuk Lee, Dynamic behavior of non-Newtonian droplets impinging on solid surfaces, Material Transactions, Vol. 54, No. 2, pp. 260-265 (2013).
  • Jae Bong Lee, Seong Hyuk Lee, Dynamic Wetting and Spreading Characteristics of a Liquid Droplet Impinging on Hydrophobic Textured Surfaces, Langmuir, Vol. 27, pp. 6565 – 6573 (2011).(DOI)
  • Jae Bong Lee, Seong Hyuk Lee, Chang Kyoung Choi, Dynamic Spreading of a Droplet Impinging on Micro-Textured Surfaces, Journal of Heat Transfer, Vol. 133, 080905-1 (2011).
  • Jae Bong Lee, Hyuk Rok Gown, Seong Hyuk Lee, Minhaeng Cho, Wetting Transition Characteristics on Microstructured Hydrophobic Surfaces, Material Transactions, Vol. 51, No. 9, pp. 1709 – 1711 (2010).(DOI)
  • Jae Bong Lee, Minhaeng Cho, The Effect of Surface Micro Texturing on Friction and Wear of Polyoxymethylene, Journal of the KSTLE, Vol. 25, No. 3, pp. 141-149 (2009).

Conference proceedings

  • Jae Bong Lee, Seong Hyuk Lee, Chang Kyoung Choi, Dynamic Spreading of a Droplet Impinging on Micro-Textured Surfaces, American Society of Mechanical Engineering (ASME)-International Mechanical Engineering Congress & Exhibition (IMECE), Vancouver, Canada, Nov. 12 - Nov. 18, 2010.
  • Jae Bong Lee, Seong Hyuk Lee, Spreading Characteristics of a Single Water Droplet Impinging on Hydrophobic Micro-Textured Metal Surfaces, 14th Annual Conference on Liquid Atomization and Spray Systems - Asia, Jeju, Korea, Oct. 21 - Oct. 22, 2010.

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