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Article
Publication date: 1 December 2005

Kevin L. Heppner and Richard W. Evitts

To present a new hybrid differencing scheme for the numerical solution of an electromigration‐diffusion equation. The value of this work is evidenced by demonstrated improvement…

Abstract

Purpose

To present a new hybrid differencing scheme for the numerical solution of an electromigration‐diffusion equation. The value of this work is evidenced by demonstrated improvement in the simulation of the Fu and Chan experiment when using the hybrid scheme.

Design/methodology/approach

A hybrid differencing scheme is developed which is based upon the solution of the pseudo‐steady state electromigration‐diffusion equation. In this scheme, a weighting parameter is calculated that varies the relative influence of the upwind node (relative to the direction of electromigration). This scheme significantly enhances the accuracy of electrochemical system mass transport models.

Findings

The hybrid scheme was compared to the upwind scheme. Use of the new hybrid scheme improved the accuracy of the model predictions by as much as 87 percent compared to the upwind scheme. However, use of the new scheme also increased the simulation time by between 6 and 43 percent. Deviations from electroneutrality and the presence of an activity coefficient gradient were detrimental to the stability of the hybrid scheme.

Research limitations/implications

This scheme is presented in the paper as an one‐dimensional (1D) scheme. However, it could be extended to more than 1D but some artificial viscosity may result.

Practical implications

The hybrid scheme developed and demonstrated herein is useful for researchers developing mass transport models of electrochemical systems. It has been proven capable of improving the accuracy of electrolyte mass transport models.

Originality/value

This is the first hybrid differencing scheme designed for the special characteristics of electrochemical mass transport systems. It greatly improves the accuracy of simulation results. This work is useful to those who mathematically model electrochemical systems.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 15 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 7 August 2017

Mayu Muramatsu, Keiji Yashiro, Tatsuya Kawada and Kenjiro Tarada

The purpose of this study is to develop a simulation method to calculate non-stationary distributions of the chemical potential of oxygen in a solid oxide fuel cell (SOFC) under…

1434

Abstract

Purpose

The purpose of this study is to develop a simulation method to calculate non-stationary distributions of the chemical potential of oxygen in a solid oxide fuel cell (SOFC) under operation.

Design/methodology/approach

The initial-boundary value problem was appropriately formulated and the appropriate boundary conditions were implemented so that the problem of non-stationary behavior of SOFC can be solved in accordance with actual operational and typical experimental conditions. The dependencies of the material properties on the temperature and partial pressure of oxygen were also elaborately introduced to realize actual material responses. The capability of the proposed simulation method was demonstrated under arbitrary operating conditions.

Findings

The steady state calculated with the open circuit voltage condition was conformable with the analytical solution. In addition, the transient states of the spatial distributions of potentials and currents under the voltage- and current-controlled conditions were successfully differentiated, even though they eventually became the same steady state. Furthermore, the effects of dense materials assumed for interconnects and current collectors were found to not be influential. It is thus safe to conclude that the proposed method enables us to simulate any type of transient simulations regardless of controlling conditions.

Practical implications

Although only uniaxial models were tested in the numerical examples in this paper, the proposed method is applicable for arbitrary shapes of SOFC cells.

Originality/value

The value of this paper is that adequate numerical simulations by the proposed method properly captured the electrochemical transient transport phenomena in SOFC under various operational conditions, and that the applicability was confirmed by some numerical examples.

Details

Engineering Computations, vol. 34 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 15 June 2010

A. Mauro, F. Arpino, N. Massarotti and P. Nithiarasu

The purpose of this paper is to describe two‐ and three‐dimensional numerical modelling of solid oxide fuel cells (SOFCs) by employing an accurate and stable fully matrix…

Abstract

Purpose

The purpose of this paper is to describe two‐ and three‐dimensional numerical modelling of solid oxide fuel cells (SOFCs) by employing an accurate and stable fully matrix inversion free finite element algorithm.

Design/methodology/approach

A general and detailed mathematical model has been developed for the description of the coupled complex phenomena occurring in fuel cells. A fully matrix inversion free algorithm, based on the artificial compressibility (AC) version of the characteristic‐based split (CBS) scheme and single domain approach have been successfully employed for the accurate and efficient simulation of high temperature SOFCs.

Findings

For the first time, a stable fully explicit algorithm has been applied to detailed multi‐dimensional simulation transport phenomena, coupled to chemical and electrochemical reactions, in fluid, porous and solid parts of a SOFC. The accuracy of the present results has been verified via comparison with experimental and numerical data available in the literature.

Originality/value

For the first time, thanks to a stabilization analysis conducted, the AC‐CBS algorithm has been successfully used to numerically solve the generalized model, applied in this paper to describe transport phenomena through free fluid channels and porous electrodes of SOFCs, without the need of further conditions at the fluid‐electrode interface.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 20 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 19 September 2008

F. Arpino, A. Carotenuto, N. Massarotti and P. Nithiarasu

The purpose of this paper is to introduce a robust mathematical model and finite element‐based numerical approach to solve solid oxide fuel cell (SOFC) problems.

Abstract

Purpose

The purpose of this paper is to introduce a robust mathematical model and finite element‐based numerical approach to solve solid oxide fuel cell (SOFC) problems.

Design/methodology/approach

A robust mathematical model is constructed by studying pros and cons of different SOFC and other fuel cell models. The finite element‐based numerical approach presented is a unified approach to solve multi‐disciplinary aspects arising from SOFC problems. The characteristic‐based split approach employed here is an efficient way of solving various flow, heat and mass transfer regimes in SOFCs.

Findings

The results presented show that both the model and numerical algorithm proposed are robust. Furthermore, the approaches proposed are general and can be easily extended to other similar problems of practical interest.

Originality/value

The model proposed is the first of this kind and the unified approach for solving flow, heat and mass transfer within a fuel cell is also novel.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 18 no. 7/8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 17 February 2020

Na Li, Lijun Fu and Kecheng Jiang

Gas evolution within lithium-ion batteries (LIBs) gives rise to safety concerns that question their applicability. The gas evolution is not only the result but also the inducement…

Abstract

Purpose

Gas evolution within lithium-ion batteries (LIBs) gives rise to safety concerns that question their applicability. The gas evolution is not only the result but also the inducement of performance deterioration of LIBs. In this paper, the growth characteristics and dynamic behavior of gas bubble on the electrode surface are studied, and the interference mechanism of gas evolution on Li-ion diffusion or Li-ion conduction within LIBs is discussed and validated by the numerical simulations.

Design/methodology/approach

First, the mathematical models and simulation method are established. The growth and flow of gas bubble in the serpentine channel on electrode surface, which results from the gas-liquid flow and the effects of surface tension, is modeled by using the multi-phase Navier-Stokes and the volume of fluid method. Integrating Butler–Volmer and Fick’s law, the mathematical model of ions transport in the electrochemical cell is set-up. Second, the motion of gas bubble is tracked, and the variations of bubble shape and characteristic parameters with time are obtained by the computed fluid dynamics (CFD) method.

Findings

Based on the CFD results, the battery models and electrochemical simulations are carried out to analyze the ionic transport characteristics. The results show that the microstructural morphology such as the serpentine channel shape and size on electrode surface are important aspects for the gas bubble growth and the local ionic transport. Li ions significantly accumulate at one side of the gas obstacle, hindering the ionic diffusion normally. When the gas bubble blocks the electrolyte, the passage of ions from the positive to the negative is interrupted, and the open circuit zone of the electrochemical cell is formed.

Originality/value

The gas evolution within LIBs is not only a result but also an inducement of its performance deterioration. The primary issues in this study are the growth characteristics and dynamic behavior of gas bubble on the electrode surface, providing the knowledge for the interference mechanism of gas evolution on ionic transport and ultimately leads to significant increase of battery resistance.

Details

Engineering Computations, vol. 37 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 2 February 2015

Linxian Ji, Chong Wang, Shouxu Wang, Wei He, Dingjun Xiao and Ze Tan

The purpose of this paper is to optimize experimental parameters and gain further insights into the plating process in the fabrication of high-density interconnections of printed…

Abstract

Purpose

The purpose of this paper is to optimize experimental parameters and gain further insights into the plating process in the fabrication of high-density interconnections of printed circuit boards (PCBs) by the rotating disc electrode (RDE) model. Via metallization by copper electrodeposition for interconnection of PCBs has become increasingly important. In this metallization technique, copper is directly filled into the vias using special additives. To investigate electrochemical reaction mechanisms of electrodeposition in aqueous solutions, using experiments on an RDE is common practice.

Design/methodology/approach

An electrochemical model is presented to describe the kinetics of copper electrodeposition on an RDE, which builds a bridge between the theoretical and experimental study for non-uniform copper electrodeposition in PCB manufacturing. Comsol Multiphysics, a multiphysics simulation platform, is invited to modeling flow field and potential distribution based on a two-dimensional (2D) axisymmetric physical modeling. The flow pattern in the electrolyte is determined by the 2D Navier–Stokes equations. Primary, secondary and tertiary current distributions are performed by the finite element method of multiphysics coupling.

Findings

The ion concentration gradient near the cathode and the thickness of the diffusion layer under different rotating velocities are achieved by the finite element method of multiphysics coupling. The calculated concentration and boundary layer thicknesses agree well with those from the theoretical Levich equation. The effect of fluid flow on the current distribution over the electrode surface is also investigated in this model. The results reveal the impact of flow parameters on the current density distribution and thickness of plating layer, which are most concerned in the production of PCBs.

Originality/value

By RDE electrochemical model, we build a bridge between the theoretical and experimental study for control of uniformity of plating layer by concentration boundary layer in PCB manufacturing. By means of a multiphysics coupling platform, we can accurately analyze and forecast the characteristic of the entire electrochemical system. These results reveal theoretical connections of current density distribution and plating thickness, with controlled parameters in the plating process to further help us comprehensively understand the mechanism of copper electrodeposition.

Details

Circuit World, vol. 41 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 10 December 2019

Yeping Peng, Ghasem Bahrami, Hossein Khodadadi, Alireza Karimi, Ahmad Soleimani, Arash Karimipour and Sara Rostami

The purpose of this study is simulation of of polymer electrolyte membrane fuel cell. Proton-exchange membrane fuel cells are promising power sources for use in power plants and…

Abstract

Purpose

The purpose of this study is simulation of of polymer electrolyte membrane fuel cell. Proton-exchange membrane fuel cells are promising power sources for use in power plants and vehicles. These fuel cells provide a high level of energy efficiency at low temperature without any pollution. The convection inside the cell plays a key role in the electrochemical reactions and the performance of the cell. Accordingly, the transport processes in these cells have been investigated thoroughly in previous studies that also carried out functional modeling.

Design/methodology/approach

A multi-phase model was used to study the limitations of the reactions and their impact on the performance of the cell. The governing equations (conservation of mass, momentum and particle transport) were solved by computational fluid dynamics (CFD) (ANSYS fluent) using appropriate source terms. The two-phase flow in the fuel cell was simulated three-dimensionally under steady-state conditions. The flow of water inside the cell was also simulated at high-current density.

Findings

The simulation results suggested that the porosity of the gas diffusion layer (GDL) is one of the most important design parameters with a significant impact on the current density limitation and, consequently, on the cell performance.

Originality/value

This study was mainly focused on the two-phase analysis of the steady flow in the fuel cell and on investigating the impacts of a two-phase flow on the performance of the cell and also on the flow in the GDL, the membrane and the catalyst layer using the CFD.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 3 April 2007

Elena Carcadea, H. Ene, D.B. Ingham, R. Lazar, L. Ma, M. Pourkashanian and I. Stefanescu

This paper aims to present a three‐dimensional computational fluid dynamics (CFD) model that simulates the fluid flow, species transport and electric current flow in PEM fuel…

4082

Abstract

Purpose

This paper aims to present a three‐dimensional computational fluid dynamics (CFD) model that simulates the fluid flow, species transport and electric current flow in PEM fuel cells.

Design/methodology/approach

The model makes use of a general‐purpose CFD software as a basic tool incorporating fuel cell specific submodels for multi‐component species transport, electrochemical kinetics, water management and electric phase potential analysis in order to simulate various processes that occur in a PEM fuel cell.

Findings

Three dimensional results for the flow field, species transport, including waster formations, and electric current distributions are presented for two test flow configurations in the PEM fuel cell. For the two cases presented, reasonable predictions have been obtained, and this provides an insight into the effect of the flow designs to the operation of the fuel cell.

Research limitations/implications

It is appreciated that the CFD modeling of fuel cells is, in general, still facing significant challenges due to the limited understanding of the complex physical and chemical processes existing within the fuel cell. The model is now under further development to improve its capabilities and undergoing further validations.

Practical implications

The model simulations can provide detailed information on some of the key fluid dynamics, physical and chemical/electro‐chemical processes that exist in fuel cells which are crucial for fuel cell design and optimization.

Originality/value

The model can be used to understand the operation of the fuel cell and provide and alternative to experimental investigations in order to improve the performance of the fuel cell.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 17 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 8 May 2009

Piergiorgio Alotto, Massimo Guarnieri and Federico Moro

The purpose of this paper is to simulate micro direct methanol fuel cells (DMFCs) for portable electronic devices by means of a non‐linear equivalent circuit based on a fully…

Abstract

Purpose

The purpose of this paper is to simulate micro direct methanol fuel cells (DMFCs) for portable electronic devices by means of a non‐linear equivalent circuit based on a fully coupled, dynamic, electrochemical model.

Design/methodology/approach

The equivalent circuit accounts for electrochemical reactions and electric current generation inside the catalyst layers, electronic and protonic conduction, fuel crossover across the membrane, mass transport of reactants inside the diffusion layers. The V‐I characteristic of the device is obtained by combining mass transport and electric equations. The transient dynamics is accounted for by an equivalent capacitance, while the slow dynamics by the mass conservation equation. The equivalent circuit is embedded in the Matlab/Simulink® dynamic model of a hybrid system, consisting of a micro fuel cell and a Li‐ion rechargeable battery.

Findings

An original equivalent circuit of a passive DMFC suitable for static and dynamic simulations under variable loading conditions is proposed and validated.

Research limitations/implications

The one‐dimensional model of the micro cell does not take into account transverse mass transfer and current density variations in the cell layers, which can be due to non‐homogeneous materials or to the complex dynamics of the convective mass flow in the reservoir and in the room air.

Practical implications

The equivalent circuit can be used for simulating the dynamic performance in realistic operating conditions when the fuel cell is used to supply the electronic equipment through a power management unit.

Originality/value

The DMFC is described from an electrical point of view as a controlled non‐linear generator; such equivalent representation is particularly suited for designing power management units for electronic portable devices.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 28 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 14 June 2011

Adriano Sciacovelli and Vittorio Verda

The aim of this paper is to investigate performance improvements of a monolithic solid oxide fuel cell geometry through an entropy generation analysis.

Abstract

Purpose

The aim of this paper is to investigate performance improvements of a monolithic solid oxide fuel cell geometry through an entropy generation analysis.

Design/methodology/approach

The analysis of entropy generation rates makes it possible to identify the phenomena that cause the main irreversibilities in the fuel cell, to understand their causes and to propose changes in the design and operation of the system. The various contributions to entropy generation are analyzed separately in order to identify which geometrical parameters should be considered as the independent variables in the optimization procedure. The local entropy generation rates are obtained through 3D numerical calculations, which account for the heat, mass, momentum, species and current transport. The system is then optimized in order to minimize the overall entropy generation and increase efficiency.

Findings

In the optimized geometry, the power density is increased by about 10 per cent compared to typical designs. In addition, a 20 per cent reduction in the fuel cell volume can be achieved with less than a 1 per cent reduction in the power density with respect to the optimal design.

Research limitations/implications

The physical model is based on a simple composition of the reactants, which also implies that no chemical reactions (water gas shift, methane steam reforming, etc.) take place in the fuel cell. Nevertheless, the entire procedure could be applied in the case of different gas compositions.

Practical implications

Entropy generation analysis allows one to identify the geometrical parameters that are expected to play important roles in the optimization process and thus to reduce the free independent variables that have to be considered. This information may also be used for design improvement purposes.

Originality/value

In this paper, entropy generation analysis is used for a multi‐physics problem that involves various irreversible terms, with the double use of this physical quantity: as a guide to select the most relevant design geometrical quantities to be modified and as objective function to be minimized in the optimization process.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 21 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

1 – 10 of 812