- Series
- Other Talks
- Time
- Friday, October 5, 2012 - 11:00am for 1 hour (actually 50 minutes)
- Location
- MRDC, Room 4211
- Speaker
- Evelyn Wang – Department of Mechanical Engineering, MIT
- Organizer
- John McCuan
Please Note: Host: David Hu. Refreshments will be served. Speaker's Bio
Nanoengineered surfaces offer new possibilities to manipulate fluidic
and thermal transport processes for a variety of applications
including lab-on-a-chip, thermal management, and energy conversion
systems. In particular, nanostructures on these surfaces can be
harnessed to achieve superhydrophilicity and superhydrophobicity, as
well as to control liquid spreading, droplet wetting, and bubble
dynamics. In this talk, I will discuss fundamental studies of droplet
and bubble behavior on nanoengineered surfaces, and the effect of such
fluid-structure interactions on boiling and condensation heat
transfer. Micro, nano, and hierarchical structured arrays were
fabricated using various techniques to create superhydrophilic and
superhydrophobic surfaces with unique transport properties. In pool
boiling, a critical heat flux >200W/cm2 was achieved with a surface
roughness of ~6. We developed a model that explains the role of
surface roughness on critical heat flux enhancement, which shows good
agreement with experiments. In dropwise condensation, we elucidated
the importance of structure length scale and droplet nucleation
density on achieving the desired droplet morphology for heat transfer
enhancement. Accordingly, with functionalized copper oxide
nanostructures, we demonstrated a 20% higher heat transfer coefficient
compared to that of state-of-the-art dropwise condensing copper
surfaces. These studies provide insights into the complex physical
processes underlying fluid-nanostructure interactions. Furthermore,
this work shows significant potential for the development and
integration of nanoengineered surfaces to advance next generation
thermal and energy systems.