Negative pressures in nanoporous membranes for thin film evaporation

2013 ◽  
Vol 102 (12) ◽  
pp. 123103 ◽  
Author(s):  
Rong Xiao ◽  
Shalabh C. Maroo ◽  
Evelyn N. Wang
Keyword(s):  
Thin Film ◽  
Nanoporous Membranes ◽  
Thin Film Evaporation ◽  
Film Evaporation ◽  
Negative Pressures

Modeling of Nanoporous Membranes for High Flux Thin Film Evaporation

2014 ◽  
Author(s):  
Zhengmao Lu ◽  
Shankar Narayanan ◽  
Daniel Hanks ◽  
Rishi Raj ◽  
Rong Xiao ◽  
...  
Keyword(s):  
Thin Film ◽  
Nanoporous Membranes ◽  
High Flux ◽  
Thin Film Evaporation ◽  
Film Evaporation

Parametric study of thin film evaporation from nanoporous membranes

2017 ◽  
Vol 111 (17) ◽  
pp. 171603 ◽  
Author(s):  
Kyle L. Wilke ◽  
Banafsheh Barabadi ◽  
Zhengmao Lu ◽  
TieJun Zhang ◽  
Evelyn N. Wang
Keyword(s):  
Thin Film ◽  
Parametric Study ◽  
Nanoporous Membranes ◽  
Thin Film Evaporation ◽  
Film Evaporation

scholarly journals Thin Film Evaporation Using Nanoporous Membranes for Enhanced Heat Transfer

2012 ◽  
Author(s):  
Rong Xiao ◽  
Shalabh C. Maroo ◽  
Evelyn N. Wang
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Thermal Management ◽  
High Heat ◽  
Heat Fluxes ◽  
Nanoporous Membranes ◽  
Transfer Coefficients ◽  
Thin Film Evaporation ◽  
Heat Transfer Coefficients ◽  
Film Evaporation

Recent advancements in integrated circuits demand the development of novel thermal management schemes that can dissipate ultra-high heat fluxes with high heat transfer coefficients. Previous study demonstrated the potential of thin film evaporation on micro/nanostructured surfaces [1–11]. Theoretical calculations indicate that heat transfer coefficients on the order of 106 W/m2K and heat fluxes of 105 W/cm2 can be achievable with water [1, 5–6]. However, in previous experimental setup, the coolant has to propagate across the surface which limits the increase in heat flux and the heat transfer coefficient, while adding complexity to the system design. This work aims to decouple the propagation of the coolant from the evaporation process through a novel experimental configuration. Thin nanoporous membranes of 13 mm diameter were used where a metal layer was deposited on the top surface to serve as a resistance heater. Liquid was supplied from the bottom of the membrane, driven through the nanopores by capillary force, and evaporated from the top surface. Heat transfer coefficient over 104 W/m2K was obtained with isopropyl alcohol (IPA) as the coolant, which is only two orders of magnitude smaller than the theoretical limit. This work offers insights into optimal experimental designs towards achieving kinetic limits of heat transfer for thin film evaporation based thermal management solutions.

Controlled Wetting in Nanoporous Membranes for Thin Film Evaporation

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Kyle L. Wilke ◽  
Banafsheh Barabadi ◽  
TieJun Zhang ◽  
Evelyn N. Wang
Keyword(s):  
Thin Film ◽  
Liquid Film ◽  
Membrane Surface ◽  
High Heat ◽  
Nanoporous Membranes ◽  
Transfer Rates ◽  
Thin Film Evaporation ◽  
Film Evaporation ◽  
High Heat Transfer ◽  
Controlled Flooding

With the ever increasing cooling demands of advanced electronics, thin film evaporation has emerged as one of the most promising thermal management solutions. High heat transfer rates can be achieved in thin films of liquids due to a small conduction resistance through the film to the evaporating interface. In thin film evaporation, maintaining a stable liquid film to attain high evaporation rates is challenging. We investigated nanoporous anodic aluminum oxide (AAO) membranes to supply liquid to the evaporating surface via capillarity. In this work, we achieved enhanced experimental control via the creation of a hydrophobic section within the nanopore. By creating a non-wetting section, the liquid is confined within the membrane to a region of well-controlled geometry. This non-wetting section also prevents flooding, where the formation of a thick liquid film degrades device performance. When heat flux is applied to the membrane surface, the liquid wicks into the membrane from the bottom and becomes pinned at the onset of the hydrophobic layer. As a result, the wetting in the membrane is controlled, flooding is prevented, and a stable evaporating surface in achieved. With this approach, thin film evaporation from nanoporous media can now be studied for varying parameters such as pore size, porosity, and location of the meniscus within the pore.

An Ultrafast Vitrification Method for Cell Cryopreservation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Fengmin Su ◽  
Nannan Zhao ◽  
Yangbo Deng ◽  
Hongbin Ma
Keyword(s):  
Thin Film ◽  
Cooling Rate ◽  
Experimental Results ◽  
Low Concentration ◽  
Temperature Range ◽  
Thin Film Evaporation ◽  
Film Evaporation ◽  
A Cell ◽  
Cryoprotective Solution ◽  
Ultrafast Cooling

Ultrafast cooling is the key to successful cell vitrification cryopreservation of lower concentration cryoprotective solution. This research develops a cell cryopreservation methodology which utilizes thin film evaporation and achieves vitrification of relatively low concentration cryoprotectant with an ultrafast cooling rate. Experimental results show that the average cooling rate of dimethylsulfoxide (DMSO) cryoprotective solution reaches 150,000 °C/min in a temperature range from 10 °C to −180 °C. The ultrafast cooling rate can remarkably improve the vitrification tendencies of the cryoprotective solution. This methodology opens the possibility for more successful cell vitrification cryopreservation.

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