Heat and Mass Transfer in Planar Anode-Supported Solid Oxide Fuel Cells: Effects of Interconnect Fuel/Oxidant Channel Flow Cross Section

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Raj M. Manglik ◽  
Yogesh N. Magar
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Reaction Rate ◽  
Three Dimensional ◽  
Bipolar Plate ◽  
Solid Oxide ◽  
Electrochemical Kinetics ◽  
Solid Matrix ◽  
Oxide Fuel ◽  
Transfer Coefficients

Heat and mass transfer in a planar anode-supported solid oxide fuel cell (SOFC) module, with bipolar-plate interconnect flow channels of different shapes are computationally simulated. The electrochemistry is modeled by uniform supply of volatile species (moist hydrogen) and oxidant (air) to the electrolyte surface with constant reaction rate via interconnect channels of rectangular, trapezoidal, and triangular cross sections. The governing three-dimensional equations for fluid mass, momentum, energy, and species transport, along with those for electrochemical kinetics, where the homogeneous porous-layer flow is in thermal equilibrium with the solid matrix, are coupled with the electrochemical reaction rate to properly account for the heat and mass transfer across flow-ducts and electrode-interfaces. The results highlight effects of interconnect duct shapes on lateral temperature and species distributions as well as the attendant frictional losses and heat transfer coefficients. It is seen that a relatively shallow rectangular duct offers better heat and mass transfer performance to affect improved thermal management of a planar SOFC.

A Study of Transport Geometry on Heat/Mass Transfer and Polarization of a Solid Oxide Fuel Cell

2006 ◽  
Author(s):  
Yan Ji ◽  
J. N. Chung ◽  
Kun Yuan
Keyword(s):  
Mass Transfer ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Heat Mass Transfer ◽  
Three Dimensional ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Transfer Coefficients ◽  
Cell Efficiency ◽  
Current Path

The main objective of this paper is to examine the effects of transport geometry on the efficiency of an electrolyte-supported solid oxide fuel cell. A three-dimensional thermo-fluid-electrochemical model is developed to the influences of channel dimensions, rib width and electrolyte thickness on the temperature, mass transfer coefficients, species concentration, local current density and power density. Results demonstrate that decreasing the height of flow channels can significantly lower the average solid temperature and improve the cell efficiency due to higher heat/mass transfer coefficient between the channel wall and flow stream, and a shorter current path. However, this improvement is limited for the smallest channel. The cell with a thicker rib width and a thinner electrolyte layer has higher efficiency and lower average temperature. Numerical simulation will be expected to help optimize the design of a solid oxide fuel cell.

Modeling of Convective Heat and Mass Transfer Characteristics of Anode-Supported Planar Solid Oxide Fuel Cells

2006 ◽  
Vol 4 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Y. N. Magar ◽  
R. M. Manglik
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Convective Heat ◽  
Porous Layer ◽  
Reaction Rate ◽  
Electrochemical Reaction ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Cross Sectional ◽  
Flow Duct

Convective heat and mass transfer in a planar, trilayer, solid oxide fuel cell (SOFC) module is considered for a uniform supply of volatile species (80%H2+20%H2O vapor) and oxidant (20%O2+80%N2) to the electrolyte surface with a uniform electrochemical reaction rate. The coupled heat and mass transfer is modeled by steady incompressible fully developed laminar flow in the interconnect ducts of rectangular cross sections for both the anode-side fuel and cathode-side oxidant flows. The governing three-dimensional mass, momentum, energy, species transfer, and electrochemical kinetics equations are solved computationally. The homogeneous porous-layer flow, which is in thermal equilibrium with the solid matrix, is coupled with the electrochemical reaction rate to properly account for the flow-duct and anode/cathode interface heat/mass transfer. Parametric effects of the rectangular flow-duct cross-sectional aspect ratio and anode porous-layer thickness on the variations in temperature and mass/species distributions, flow friction factor, and convective heat transfer coefficient are presented. The thermal and hydrodynamic behavior is characterized for effective convective cooling performance, and interconnect channels of cross-sectional aspect ratio of ∼2-3 along with relative anode porous-layer thickness of ∼0.5-1.5 are seen to provide optimal thermal management and species mass transport benefits in the SOFC module.

Thermal and Hydrodynamic Modeling of Fully-Developed Convection in Anode-Supported Planar Solid Oxide Fuel Cells

2005 ◽  
Author(s):  
Yogesh N. Magar ◽  
Raj M. Manglik
Keyword(s):  
Porous Electrode ◽  
Three Dimensional ◽  
Active Surface ◽  
Solid Oxide ◽  
Electrochemical Kinetics ◽  
Solid Matrix ◽  
Oxide Fuel ◽  
Porous Layers ◽  
Porous Anode ◽  
Flow Duct

Uniform supply of volatile species to an active surface along with the oxidant flow to sustain the surface electrochemical reaction, and its effective cooling in an anode supported solid oxide fuel cell (SOFC) is modeled. Three-dimensional nonlinear partial differential governing equations for the conservation of mass, momentum, energy, species, and electrochemical kinetics for both the anode and cathode ducts for steady laminar, incompressible flow are solved computationally. A planar, tri-layer SOFC module, which consists of porous anode and cathode layers, solid electrolyte and rectangular flow ducts, is considered. The homogenous porous electrode layers are characterized by constant porosity, permeability, and thermal conductivity, and the fluid in these porous layers is considered to be in thermal equilibrium with the solid matrix. The computational results highlight the influence of fuel and oxidant flow duct aspect ratio and porous anode-layer depth on the friction factor and Nusselt number for typical electrochemical loads, and the consequent thermal signatures of the SOFC.

Numerical Analysis of Heat/Mass Transfer and Electrochemical Reaction in an Anode-Supported Flat-Tube Solid Oxide Fuel Cell

2006 ◽  
Author(s):  
Masayuki Suzuki ◽  
Naoki Shikazono ◽  
Koji Fukagata ◽  
Nobuhide Kasagi
Keyword(s):  
Mass Transfer ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Electrochemical Reaction ◽  
Cell Model ◽  
Flow Direction ◽  
Three Dimensional ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Flat Tube

Three-dimensional heat and mass transfer and electrochemical reaction in an anode-supported flat-tube solid oxide fuel cell (FT-SOFC) are studied. Transport and reaction phenomena mainly change in the streamwise direction. Exceptionally, hydrogen and water vapor have large concentration gradients also in the cross section perpendicular to the flow direction, because of the insufficient mass diffusion in the porous anode. Based on these results, we develop a simplified one-dimensional cell model. The distributions of temperature, current, and overpotential predicted by this model show good agreement with those obtained by the full three-dimensional simulation. We also investigate the effects of pore size, porosity and configuration of the anode on the cell performance. Extensive parametric studies reveal that, for a fixed three-phase boundary (TPB) length, rough material grains are preferable to obtain higher output voltage. In addition, when the cell has a thin anode with narrow ribs, drastic increase in the volumetric power density can be achieved with small voltage drop.

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