
Prof. Gangtao LIANG
Dalian University of Technology, China
Title: Condensation Mode Transition and Droplet Jumping on Microstructured Surface
Abstract:
Condensation enhancement on the micropillar structured surfaces is
studied using a three-dimensional lattice Boltzmann model, and the optimal
micropillar configuration is assessed. The impacts brought by varying micropillar
geometric parameters on heat transfer and droplet dynamics during dropwise-to-
filmwise transition are explored. Increasing micropillar width and spacing or
decreasing height accelerates nucleation and improves nucleation density in the
dropwise condensation stage, while radial contraction of the liquid film is hindered
and the heat transfer area is increased in the filmwise condensation stage. Compared
with its plain competitor, the maximum number of the isolated droplets is increased
by 525%, the nucleation time is advanced by 57.1% and the heat flux is increased by
187.4% on the optimal micropillar surface. The entire condensation process spanning
over nucleation, coalescence and jumping of multiple condensate droplets on the
micropillar surface is realized using the present three-dimensional lattice Boltzmann
model for the first time. The effects of height and spacing of micropillar arrays on
jumping height and velocity are analyzed. The results show that the micropillar
height poses little effect on the jumping height and velocity when the micropillar
spacing is 0.1. When the micropillar spacing is 0.15, the jumping height and velocity
first increase but then decrease with the increase of the micropillar height. Finally, the
condensation heat transfer mechanism under different subcooling on the hierarchical
surface is analyzed in detail.
Biography:
Prof. Liang received his B.Eng. in 2009 and Ph.D. in 2014 from Dalian University of Technology, where he remained as a faculty member. He undertook his postdoctoral research from 2015 to 2017 at Purdue University Boiling and Two-Phase Flow Laboratory (PU-BTPFL), where he was dedicated to experimental investigation and theoretical modeling of two-phase flow and heat transfer. He was appointed to Associate Professor in advance in 2016 because of his outstanding work in the areas of heat transfer and fluid mechanics. His primary research interests are two-phase flow and heat transfer, covering droplets impingement, spray cooling, micro-channel flow boiling and condensation, horizontal-tube falling film evaporation, and boiling enhancement. He has published over 80 papers, including more than 50 archival journal papers in Int. J. Heat Mass Transfer, Int. Commun. Heat Mass Transfer, Exp. Therm. Fluid Sci., Acta Mech., Numer. Heat Transfer, and Ind. Eng. Chem. Res. He has been internationally recognized for his great contributions to the droplets impact research and a series of high-quality review papers for two-phase heat transfer topics. He is currently Advisory Board Member of Heat Transfer Division in Cambridge Scholars Publishing, International Advisory Board Member of Thermal Science Journal, and Editorial Board Member of Fluid Dynamics & Materials Processing. He also serves as an outstanding reviewer for many international journals.