DEPARTMENT OF MECHANICAL AND MATERIALS ENGINEERING
presents an invited lecture on
FLOW BOILING PROCESSES IN MICRO DOMAINS –
EXPERIMENTAL CHALLENGES AND OPPORTUNITIES
YOAV PELES
Lockheed Martin Endowed Professor and Chairman
Department of Mechanical and Aerospace Engineering, University of Central Florida
Date:
Time:
Room:
February 13, 2015 (FRIDAY)
3:00 - 4:00 p.m.
EC1115
Flow boiling in micro domains has received much interest since the early 2000.
Fundamental knowledge pertinent to boiling heat transfer in diminishing length scales is
lacking primarily, because local transient measurements at the micro scale are very
challenging. Main issues include significant conjugate conduction/convection processes
and the lack of high frequency synchronized temperature/flow visualization
measurements.
In this presentation, a new hybrid numerical-experimental method that overcomes
major obstacles inhibiting progress pertinent to this important field is presented. A new
parameter, termed the S coefficient, which allows accounting for the conduction process,
and therefore, isolating the convection process, is introduced and numerically
calculated. It is then demonstrated in three high speed experimental measurements.
Surface temperatures were obtained at high frequencies (O(10kHz)) using micron size
thermistors. Boiling events were simultaneously visualized and used in conjunction with
transient temperature measurements and the S coefficient to infer processes controlling
heat transfer in a microchannel.
It was shown that high thermal conductivity substrates typically used to form
microchannels, such as silicon and copper, are not suitable for elucidating fundamental
transient processes in microchannels. Low thermal conductivity materials, such as Pyrex
and Benzocyclobutene (BCB), are more applicable. However, this can only be done
through careful numerical analysis of the conduction heat transfer within the solid
structure used to form the microchannel.
Biographical sketchof the invited speaker:
Professor Yoav Peles is the Lockheed Martin Endowed Professor and the Chair of the Mechanical
and Aerospace Department at the University of Central Florida (UCF). Prior to joining UCF, he was with
the Department of Mechanical, Aerospace and Nuclear Engineering (MANE) at Rensselaer Polytechnic
Institute (RPI). He received his doctorate degree at Technion in Israel.
He studies convective heat transfer in micro domains, and published more than 90 peer reviewed
journal papers, about 50 conference papers, has several patents, written four book chapters, and is the
author of a book entitled Contemporary Perspective on Flow Boiling Instabilities in Microchannels.
Professor Peles organized several international conferences and workshops including the first Gordon
Research Conference on Micro and Nano Scale Phase Change Heat Transfer, the International Workshop
on Micro and Nano Structures for Phase Change Heat transfer, and the ASME International Conference
on Nanochannels, Microchannels, and Minichannels 2013 (ICNMM 2013).