scholarly journals Effect of stress-dependent activation enthalpy on electrochemical reaction and diffusion-reaction-induced stress in spherical electrodes

2019 ◽  
Vol 14 ◽  
pp. 102407
Author(s):  
Liangxinbu Lyu ◽  
Bailin Zheng ◽  
Kai Zhang ◽  
Feng Wang ◽  
Siyuan Zhan
Keyword(s):  
Activation Enthalpy ◽  
Electrochemical Reaction ◽  
Diffusion Reaction ◽  
Induced Stress ◽  
Stress Dependent ◽  
And Diffusion ◽  
Reaction And Diffusion

Decoupling Electrochemical Reaction and Diffusion Processes in Ionically-Conductive Solids on the Nanometer Scale

ACS Nano ◽  
2010 ◽  
Vol 4 (12) ◽  
pp. 7349-7357 ◽  
Author(s):  
Nina Balke ◽  
Stephen Jesse ◽  
Yoongu Kim ◽  
Leslie Adamczyk ◽  
Ilia N. Ivanov ◽  
...  
Keyword(s):  
Diffusion Processes ◽  
Electrochemical Reaction ◽  
Nanometer Scale ◽  
And Diffusion ◽  
Reaction And Diffusion

A computational model for diffusion-reaction-deformation coupled problems and its finite element implementation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bao Qin ◽  
Yexin Zhou ◽  
Zheng Zhong
Keyword(s):  
Finite Element ◽  
Chemical Reaction ◽  
Reaction Rate ◽  
Diffusion Processes ◽  
Diffusion Reaction ◽  
Governing Equations ◽  
Content Type ◽  
Finite Element Software ◽  
And Diffusion ◽  
Reaction And Diffusion

PurposeA diffusion-reaction-deformation coupled model is employed and implemented as a user-defined element (UEL) subroutine in the commercial finite element software package ABAQUS.Design/methodology/approachChemical reaction and diffusion are treated as two distinct processes by introducing the extent of reaction and the diffusion concentration as two kinds of independent variables, for which the independent governing equations for chemical reaction and diffusion processes are obtained. Furthermore, an exponential form of chemical kinetics, instead of the linearly phenomenological relation, between the reaction rate and the chemical affinity is used to describe reaction process. As a result, complex chemical reaction can be simulated, no matter it is around or away from equilibrium.FindingsTwo numerical examples are presented, one for validation of the model and another for the modeling of the deflection of a plane caused by a chemical reaction.Originality/value1. Independent governing equations for diffusion and reaction processes are given. 2. An exponential relation between the reaction rate and its driving force is employed. 3. The UEL subroutine is used to implement the finite element procedure.

Solid-State Reaction and Diffusion Behaviors of CaFe2O4 and TiO2 at 1373 K to 1473 K

2021 ◽  
Author(s):  
Mingrui Yang ◽  
Junyi Xiang ◽  
Chenguang Bai ◽  
Xuangeng Zhou ◽  
Zhongci Liu ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
And Diffusion ◽  
Diffusion Behaviors ◽  
Reaction And Diffusion

A numerical study of the mechanism of injection-induced and triggered seismicity at the Pohang Enhanced Geothermal Systems project, South Korea

2021 ◽  
Author(s):  
Kwang-Il Kim ◽  
Hwajung Yoo ◽  
Seheok Park ◽  
Juhyi Yim ◽  
Linmao Xie ◽  
...  
Keyword(s):  
South Korea ◽  
Numerical Study ◽  
Geothermal System ◽  
Enhanced Geothermal Systems ◽  
Hydraulic Stimulation ◽  
Triggered Seismicity ◽  
Induced Stress ◽  
Shear Slip ◽  
Stress Dependent ◽  
The Impact

<p>Hydraulic stimulation for the creation of an Enhanced Geothermal System (EGS) reservoir could potentially reactivate a nearby fault and result in man-made earthquakes. In November 15, 2017, an M<sub>w</sub> 5.5 earthquake, the second largest after the initiation of the South Korean national instrumental monitoring system, occurred near an EGS project in Pohang, South Korea. The earthquake occurred on a previously unmapped fault, that is here denoted the M<sub>w</sub> 5.5 Fault. A number of previous studies to model the hydraulic stimulation in the Pohang EGS project have been carried out to identify the mechanism of seismic events. Those previous studies focused on coupled hydro-mechanical processes without the consideration of pre-existing fractures and thermal effects. This study presents an investigation of the mechanisms of induced and triggered seismicity in the Pohang EGS project through three-dimensional coupled thermo-hydro-mechanical numerical simulations. Fractures intersecting the open-hole sections of two deep boreholes, PX-1 and PX-2, clearly indicated by field observations are modeled along with the M<sub>w</sub> 5.5 Fault. Models of stress-dependent permeability models are calibrated based on the numerical reproduction of the pressure-time evolution during the field hydraulic stimulations. The Coulomb failure stress change at the M<sub>w</sub> 5.5 Fault is calculated to quantify the impact of five hydraulic stimulations. In the case of PX-2 stimulations, the pore pressure buildup results in a volumetric expansion of the reservoir and thereby the perturbation of stresses is transferred to the M<sub>w</sub> 5.5 Fault. The volumetric contraction of the reservoir by the temperature reduction could slightly perturb the stress distribution at the M<sub>w</sub> 5.5 Fault. In the case of PX-1 stimulations, shear slip of the PX-1 fracture is explicitly modeled. The modeling shows that transfer of the shear stress drop by the shear slip stabilizes the M<sub>w</sub> 5.5 Fault, which is consistent with the field observation that the seismicity was not induced at the M<sub>w</sub> 5.5 Fault by the PX-1 stimulations. The cooling-induced thermal stress additionally reduces the effective normal stress of PX-1 fracture. Thus, some additional shear slip of the PX-1 fracture is induced by the thermal effect. However, the modeling shows that for both PX-1 and PX-2 stimulations, thermally-induced stress perturbations are very small compared to pressure-induced stress perturbations.</p>

Detailed Electrochemistry and Gas Transport in a SOFC Anode Using the Lattice Boltzmann Method

2006 ◽  
Author(s):  
Kyle N. Grew ◽  
Abhijit S. Joshi ◽  
Aldo A. Peracchio ◽  
Wilson K. S. Chiu
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Electrochemical Reaction ◽  
Coupled Model ◽  
Transport Processes ◽  
Flux Boundary Conditions ◽  
Sofc Anode ◽  
Boltzmann Method ◽  
Electrochemical Model ◽  
And Diffusion

A coupled electrochemical reaction and diffusion model has been developed and verified for investigation of mass transport processes in Solid Oxide Fuel Cell (SOFC) anode triple-phase boundary (TPB) regions. The coupled model utilizes a two-dimensional (2D), multi-species Lattice Boltzmann Method (LBM) to model the diffusion process. The electrochemical model is coupled through localized flux boundary conditions and is a function of applied activation overpotential and the localized hydrogen and water mole fractions. This model is designed so that the effects of the anode microstructure within TPB regions can be examined in detail. Results are provided for the independent validation of the electrochemical and diffusion sub-models, as well as for the coupled model. An analysis on a single closed pore is completed and validated with a Fick's law solution. A competition between the electrochemical reaction rate and the rate of mass transfer is observed to be dependent on inlet hydrogen mole fraction. The developed model is presented such that future studies on SOFC anode microstructures can be completed.

scholarly journals Reaction-Diffusion Systems: Self-Balancing Diffusion and the Use of the Extent of Reaction as a Descriptor of Reaction Kinetics

2019 ◽  
Author(s):  
Miloslav Pekař
Keyword(s):  
Reaction Kinetics ◽  
Reaction Diffusion ◽  
Reaction Diffusion Systems ◽  
Diffusion Systems ◽  
And Diffusion ◽  
Reaction And Diffusion

Self-balancing diffusion is a concept which restricts the introduction of extents of reactions. This concept is analyzed in detail for mass- and molar-based balances of reaction-diffusion mixtures, in relation to non-self-balancing cases, and with respect to its practical consequences. A note on a recent generalization of the concept of reaction and diffusion extents is also included.<br>

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