Microscale Transport Processes and Interfacial Force Field Characterization in Micro-cooling Devices

2009 ◽  
pp. 113-130
Author(s):  
Sunando DasGupta
Author(s):  
Pratap Rama ◽  
Yu Liu ◽  
Rui Chen ◽  
Hossein Ostadi ◽  
Kyle Jiang ◽  
...  

This work reports a feasibility study into the combined full morphological reconstruction of fuel cell structures using X-ray computed micro- and nanotomography and lattice Boltzmann modeling to simulate fluid flow at pore scale in porous materials. This work provides a description of how the two techniques have been adapted to simulate gas movement through a carbon paper gas diffusion layer (GDL). The validation work demonstrates that the difference between the simulated and measured absolute permeability of air is 3%. The current study elucidates the potential to enable improvements in GDL design, material composition, and cell design to be realized through a greater understanding of the nano- and microscale transport processes occurring within the polymer electrolyte fuel cell.


2015 ◽  
Vol 10 (2) ◽  
pp. 021002 ◽  
Author(s):  
Tigran M. Abramyan ◽  
James A. Snyder ◽  
Jeremy A. Yancey ◽  
Aby A. Thyparambil ◽  
Yang Wei ◽  
...  

Author(s):  
Siavash Zare ◽  
Mohammad Javad Abdolhosseini Qomi

We develop Mg/C/O/H ReaxFF parameter sets for two environments: an aqueous force field for magnesium ions in solution and an interfacial force field for minerals and mineral-water interfaces. Since magnesium...


2003 ◽  
Author(s):  
Saeed Moghaddam ◽  
Kenneth T. Kiger

Boiling heat transfer has been the subject of research for many years, with a substantial amount of effort devoted to understanding the microscale transport processes of nucleate boiling. This information is essential to determine appropriate expressions for the boiling heat transfer coefficient. As a result, several different competing models based on the bubbling dynamics and its associated heat transfer mechanisms have been hypothesized to account for the sensible and latent heat transport and liquid motion adjacent to the heat transfer surface. Many of the early models were based on the assumptions that growth, departure and the associated pumping action of the bubbles are responsible for heat transfer during nucleate boiling. Jakob [1] and Rohsenow [2] were apparently the first to postulate that the process of growth and departure of the bubble is responsible for the induced motion of the liquid adjacent to the heat transfer, as in any single-phase convection process. Rohsenow [2] modeled the heat transfer by using bubble diameter as a characteristic length to determine a Nusselt number based on a defined Reynolds and Prandtl number. Even with the same line of reasoning, Rohsenow’s analysis resulted in a different formulation compared to Froster and Zober [3], who implemented an alternate hypothesis for the velocity of the bubble interface used in defining the Reynolds number. Other models of this nature were also proposed by Forster and Greif [4] and Zuber [5].


2002 ◽  
Vol 124 (4) ◽  
pp. 729-738 ◽  
Author(s):  
Ying-Xin Wang ◽  
Ling Zheng ◽  
Joel L. Plawsky ◽  
Peter C. Wayner,

The microscale transport processes in droplet condensation and removal due to interfacial phenomena were studied. In particular, this paper concerns the movement of a condensed ethanol sessile drop into a concave liquid film in the corner. An improved image analyzing procedure was used to evaluate the curvatures and contact angles for both the drop and the concave corner meniscus at different condensation rates. The experimental results demonstrated that the condensate removal rate was a function of the curvature and contact angle, which self-adjust to give the necessary force field. The use of a dimensionless, shape dependent, force balance was demonstrated. For small drops, the intermolecular force was found to be much larger than the gravitational force and dominated droplet removal. Microscale pressure fields can be experimentally measured whereas interfacial temperature differences cannot.


AIChE Journal ◽  
1995 ◽  
Vol 41 (9) ◽  
pp. 2140-2149 ◽  
Author(s):  
Sunando Dasgupta ◽  
Joel L. Plawsky ◽  
Peter C. Wayner

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