Interfacial transport characteristics between heterogeneous porous composite media for effective mass transfer in fuel cells

2019 ◽  
Vol 43 (7) ◽  
pp. 2990-3005 ◽  
Author(s):  
Jiawen Liu ◽  
Seungho Shin ◽  
Sukkee Um
Keyword(s):  
Mass Transfer ◽  
Fuel Cells ◽  
Effective Mass ◽  
Composite Media ◽  
Porous Composite ◽  
Interfacial Transport

Effective Mass-Transfer Area in a Pilot Plant Column Equipped with Structured Packings and with Ceramic Rings

1994 ◽  
Vol 33 (3) ◽  
pp. 647-656 ◽  
Author(s):  
M. Henriques de Brito ◽  
U. von Stockar ◽  
A. Menendez Bangerter ◽  
P. Bomio ◽  
M. Laso
Keyword(s):  
Mass Transfer ◽  
Effective Mass ◽  
Pilot Plant ◽  
Structured Packings

scholarly journals Heat and Mass Transfer and Two Phase Flow in Hydrogen Proton Exchange Membrane Fuel Cells and Direct Methanol Fuel Cells

2003 ◽  
Author(s):  
Hang Guo ◽  
Chong Fang Ma ◽  
Mao Hai Wang ◽  
Jian Yu ◽  
Xuan Liu ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Direct Methanol Fuel Cells ◽  
Proton Exchange ◽  
Phase Flow ◽  
Two Phase ◽  
Direct Methanol ◽  
Methanol Fuel Cells ◽  
Exchange Membrane

Fuel cells are related to a number of scientific and engineering disciplines, which include electrochemistry, catalysis, membrane science and engineering, heat and mass transfer, thermodynamics and so on. Several thermophysical phenomena such as heat transfer, multicomponent transport and two phase flow play significant roles in hydrogen proton exchange membrane fuel cells and direct methanol fuel cells based on solid polymer electrolyte membrane. Some coupled thermophysical issues are bottleneck in process of scale-up of direct methanol fuel cells and hydrogen proton exchange membrane fuel cells. In present paper, experimental results of visualization of condensed water in fuel cell cathode microchannels are presented. The equivalent diameter of the rectangular channel is 0.8mm. Water droplets from the order of 0.08mm to 0.8mm were observed from several different locations in the channels. Several important problems, such as generation and change characteristics of water droplet and gas bubble, two phase flow under chemical reaction conditions, mass transfer enhancement of oxygen in the cathode porous media layer, heat transfer enhancement and high efficiency cooling system of proton exchange membrane fuel cells stack, etc., are discussed.

scholarly journals Description of Cumbeba (Tacinga inamoena) Waste Drying at Different Temperatures Using Diffusion Models

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1818
Author(s):  
João P. L. Ferreira ◽  
Wilton P. Silva ◽  
Alexandre J. M. Queiroz ◽  
Rossana M. F. Figueirêdo ◽  
Josivanda P. Gomes ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Effective Mass ◽  
Sample Surface ◽  
Fruit Production ◽  
Diffusion Models ◽  
Convective Drying ◽  
Convective Mass Transfer ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Drying Conditions

One approach to improve sustainable agro-industrial fruit production is to add value to the waste generated in pulp extraction. The processing of cumbeba (Tacinga inamoena) fruits generates a significant amount of waste, which is discarded without further application but can be a source of bioactive compounds, among other nutrients. Among the simplest and most inexpensive forms of processing, convective drying appears as the first option for the commercial utilization of fruit derivatives, but it is essential to understand the properties of mass transfer for the appropriate choice of drying conditions. In this study, cumbeba waste was dried at four temperatures (50, 60, 70 and 80 °C). Three diffusion models were fitted to the experimental data of the different drying conditions. Two boundary conditions on the sample surface were considered: equilibrium condition and convective condition. The simulations were performed simultaneously with the estimation of effective mass diffusivity coefficients (Def) and convective mass transfer coefficients (h). The validation of the models was verified by the agreement between the theoretical prediction (simulation) and the experimental results. The results showed that, for the best model, the effective mass diffusivities were 2.9285 × 10−9, 4.1695 × 10−9, 8.1395 × 10−9 and 1.2754 × 10−8 m2/s, while the convective mass transfer coefficients were 6.4362 × 10−7, 8.7273 × 10−7, 8.9445 × 10−7 and 1.0912 × 10−6 m/s. The coefficients of determination were greater than 0.995 and the chi-squares were lower than 2.2826 × 10−2 for all simulations of the experiments.

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