Micro-fluidics (Re < 1) has been in the focus of the scientific community for the past 4 decades, while there is now expanding interest is addressing high speed micro-flow processes (Re > 500), i.e. the reference here to "Hyper-Micro Fluidics". Much of the interest regards micro-two-phase cooling of high power electronics where these “unruly" flows need to be stabilised and well divided into dozens (if not hundreds) of parallel cooling channels as small as 100 microns in size. Hence, while the goals are the same (modeling and flow control) as in micro-fluidics, the challenges are quite different with the addition of evaporating and thus accelerating fluids and addition of a second fluid phase (vapor). In addition, with the coming of self-driving cars and 5G smartphones, a huge upward serge is anticipated in the use of electricity by telecommunications and datacenters, currently increasing by 15% a year (representing 4% of all electricity consumption). This is not sustainable when one throws in also charging of all the planned EV’s…thus creating a sort of “perfect storm” in electrical energy consumption in the coming decade that needs to be addressed now. The present lecture will provide an overview of micro-two-phase cooling, new measurement techniques, flow phenomena, VOF and FEM numerical modeling, energy-free passive cooling techniques, etc. drawn primarily from the LTCM lab’s experience.
About the Speaker
John R. Thome is Professor of Heat and Mass Transfer at the Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland since 1998 (obtaining his PhD at Oxford University in 1978). He was an Assistant/Associate Professor at Michigan State University from 1978-1984, leaving to set up his own international consulting company from 1985-1998 before joining the EPFL. He is the author of five books and has published over 230 journal papers on the fundamental aspects of microscale and macroscale two-phase flow, boiling/condensation heat transfer and micro-two-phase cooling systems, proposing over 100 two-phase flow and heat transfer prediction methods applicable to macro and micro scale processes, including his widely used flow pattern based methods for boiling, condensation and microchannels. He received the ASME Heat Transfer Division's Journal of Heat Transfer Best Paper Award in 1998, the 2011-2 Very Highly Commended Paper Award from the Int. J. of Refrigeration, the United Kingdom’s Institute of Refrigeration J.E. Hall Gold Medal in 2008 for his work on microscale refrigeration heat transfer, the 2010 ASME Heat Transfer Memorial Award, an ASME 75th Anniversary Medal from the Heat Transfer Division, the ICEPT-HDP 2012 Best Paper Award on a 3D-IC prototype with interlayer cooling (12'000 TVS's and 260 microchannels inside), the ASME Journal of Electronics Packaging Best Paper Award at IMECE in 2014, and the Outstanding Paper Award at InterPACK2017. He received the prestigious 2017 Nusselt-Reynolds Prize. He founded the Virtual International Research Institute of Two-Phase Flow and Heat Transfer in 2014, now with 27 participating universities to promote research collaboration and education (see http://2phaseflow.org). According to Google Scholar, he has over 19’700 citations.
Host: Professor Xiaofei Wang