The Fluids and Thermal Engineering Research Group, warmly invites you to attend their seminar
on 23 January at 14:30 - Free to attend
Influence of surface wettability on pool boiling onset and bubble nucleation: experimental and multiscale numerical results
Guest Speaker:
Professor Marco Marengo
Professor of Thermal Engineering at the School of Computing Engineering and Mathematics, Director of the Advanced Engineering Centre and Chair of the Engineering Industrial Advisory Board at the University of Brighton, UK.
Abstract: The miniaturization of electronic components and their always increasing integration, with the fascinating perspective of micro-robots, micro- and nano-systems for sensors and fluid manipulation, drives various and important technological advancements. Thermal management in micro- and nanoscale systems is currently a bottleneck in the further development of these technologies. Among the different ways to remove this big amount of heat, phase-change heat transfer seems to be one of the most efficient. It permits to obtain significant heat fluxes, spreading the heat from hot spots to larger heat sinks. Even if they are efficient, these systems present some drawbacks such as the gravity dependence or the superheat temperature at the onset of boiling, for example. Nowadays, one of biggest challenge is to reduce as much as possible the superheat temperature needed to reach the boiling. The influence of surface wettability on boiling onset has been argued since decades, but up to now it was difficult to understand and measure this single effect due to the dominant and apparently inextricable role of the surface roughness and the cavity distribution on the surface. In fact most of the boiling onset models are still addressing the critical role of cavity size and surface tension for the initial appearance of nucleation sites. We have performed a series of experiments on ultra-smooth surfaces with and without a highly resistant grafted monolayer. The results obtained show that a decrease of the surface wettability allows to achieve boiling in an easier way. This has been quantified by the acquisition of boiling curves and by image analysis, for a wide range of wettabilities, on metallic and glass substrates. A novel theoretical approach, based on MD simulations, is proposed, as long as an innovative numerical methodology using Mesoscale Models and Simulations of Bubble Nucleation. Co-authors: Anastasios Georgoulas, Francesco Magaletti.
Biography: Marco Marengo is Professor of Thermal Engineering at the School of Computing Engineering and Mathematics, Director of the Advanced Engineering Centre and Chair of the Engineering Industrial Advisory Board at the University of Brighton, UK. In 1991 Prof. Marengo got a Master Degree in Physics cum laude at the University of Turin on Dynamical Systems and in 1996 he received a Ph.D. in Energetics at the Polytechnic of Milan. From 1998 to 2002 he has been Assistant Professor of Thermal Physics and then, until 2016, Associate Professor of Thermal Physics at the University of Bergamo, Italy. In 2014 he was appointed Full Professor of Thermal Engineering at the University of Brighton. From 2019 he is Associate Editor of the International Journal of Multiphase Flows. Editor-in-Chief of the Section ‘Thermal Management” of the MDPI Journal Energies. Guest Editor of MDPI “Energies” Journal, Advanced Thermal Simulation of Energy Systems. From 2009 to 2018 he has been European Editor of the International Journal "Atomization & Sprays". He is UK representative on the board of the International Heat Pipe Conference. Prof. Marengo is Adjunct Professor at York University, Toronto, Canada and Senior Research Fellow at the National Science Foundation of Portugal, Center for Innovation, Technology and Policy Research - IN+, Lisbon, Portugal. From 2005 to 2018 Marengo was Visiting Professor at the University of Mons-Hainaut. He has founded three spin-off companies. He is member of the scientific committees of various international conferences and Editorial board members of various scientific journals. Since 2015 he is co-director of the successful Course series LIDESP on “Advanced Course in Liquid Interfaces, Drops and Sprays” and since 2018 he is Chair of the International Workshop SWEP on “Surface Wettability Effect on Phase Change Phenomena”.
He is leading the ESA Pulsating Heat Pipe scientific team, he is active in many ESA parabolic campaigns. He published more than 330 scientific papers, among which more than 80 in peer-reviewed International Journals. Prof. Marengo is an internationally recognised expert in fundamental and applied research of two-phase systems, associated with phase change heat transfer, for space and ground applications as well as in experimental and numerical modelling of phase-change heat transfer.