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Full-Text Articles in Engineering
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
Ralph E. White
Secondary current density distributions are of interest
to cell designers. The purpose of this note is to illustrate
how to use an existing numerical method to determine
these distributions for cells that contain conducting and
nonconducting bodies between the main anode and cathode.
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
Ralph E. White
Secondary current density distributions are of interestto cell designers. The purpose of this note is to illustratehow to use an existing numerical method to determinethese distributions for cells that contain conducting andnonconducting bodies between the main anode and cathode.
Parallel Plate Electrochemical Reactor Model, Ralph E. White, Mike Bain, Mike Raible
Parallel Plate Electrochemical Reactor Model, Ralph E. White, Mike Bain, Mike Raible
Ralph E. White
No abstract provided.
Predicting Shunt Currents In Stacks Of Bipolar Plate Cells With Conducting Manifolds, H. S. Burney, Ralph E. White
Predicting Shunt Currents In Stacks Of Bipolar Plate Cells With Conducting Manifolds, H. S. Burney, Ralph E. White
Ralph E. White
A method is presented for predicting shunt currents in stacks of bipolar plate cells with conducting manifolds. The method is based on the requirement that the potential drop through the solution in a manifold be large enough to force current to leave the solution and to enter the conducting manifold. The current that leaves the solution in the manifold enters the conducting manifold at the anode end of the stack and returns to the solution at the cathode end. This could cause catastrophic failure of a manifold.
Thermal Mathematical Modeling Of A Multicell Common Pressure Vessel Nickel-Hydrogen Battery, Junbom Kim, T. V. Nguyen, Ralph E. White
Thermal Mathematical Modeling Of A Multicell Common Pressure Vessel Nickel-Hydrogen Battery, Junbom Kim, T. V. Nguyen, Ralph E. White
Ralph E. White
A two-dimensional and time-dependent thermal model of a multicell common pressure vessel (CPV) nickel-hydrogen battery was developed. A finite element solver called PDE/Protran was used to solve this model. The model was used to investigate the effects of various design parameters on the temperature profile within the cell. The results were used to help find a design that will yield an acceptable temperature gradient inside a multicell CPV nickel-hydrogen battery. Steady-state and unsteady-state cases with a constant heat generation rate and a time-dependent heat generation rate were solved.
Current Distribution In A Horizon® Lead-Acid Battery During Discharge, Z. Mao, Ralph E. White, B. Jay
Current Distribution In A Horizon® Lead-Acid Battery During Discharge, Z. Mao, Ralph E. White, B. Jay
Ralph E. White
A simple mathematical model is presented and used to analyze the potential and current distributions in a HORIZON® sealed lead-acid battery. It was found that an increase in the thickness of an electrode would not enhance the discharge rate of that electrode; instead, it causes the transfer current distribution to be less uniform in the electrode. Also, the ohmic drop across the separator would decrease with a decrease in the thickness of the separator more rapidly when the thickness is small than when it is large. In addition, it was found that efficient high-capacity, high-rate electrodes must consider the electrode …
A Simple Model For A Zinc/Bromine Flow Cell And Associated Storage Tanks, G. D. Simpson, Ralph E. White
A Simple Model For A Zinc/Bromine Flow Cell And Associated Storage Tanks, G. D. Simpson, Ralph E. White
Ralph E. White
A simple model for a parallel plate, zinc/bromine flow cell and associated storage tanks is presented and used to make time-dependent predictions for various quantities in the system. The model is based on a previously published algebraic model of the cell at steady-state and time-dependent, first-order differential equations for the storage tanks. The Butler-Volmer equation is used for the electrochemical reactions, and the homogeneous reaction between bromine and bromide is included. The model predictions indicate that the charging operation of a zinc/bromine battery can be significantly improved by using a storage tank with a larger residence time for the bromine …
Measurements Of The Fundamental Thermodynamic Parameters Of Li/Bcx And Li/Socl2 Cells, E. E. Kalu, Ralph E. White, E. C. Darcy
Measurements Of The Fundamental Thermodynamic Parameters Of Li/Bcx And Li/Socl2 Cells, E. E. Kalu, Ralph E. White, E. C. Darcy
Ralph E. White
The thermodynamic data needed to estimate the heat generation characteristics of Li/BCX and Li/SOCl2 cells were determined using two experimental techniques, equilibrium or reversible cell discharge and measurement of open circuitpotential as a function of temperature. The results obtained showed that the reversible cell potential (Er), the temperature dependence of the reversible cell potential (dEr/dT) and thermoneutral potential (Eh) of the BCX cell were respectively, Er,25oc = 3.74 V, dEr/dT = –0.857 ± 0.198 mV/K and Eh = 3.994 ± 0.0603 V. The respective values obtained for the Li/SOCl2 cell were Er,25oc = 3.67 V, dEr/dT = –0.776 ± 0.255 …
Modeling Lithium Intercalation In A Porous Carbon Electrode, Gerardine G. Botte, Ralph E. White
Modeling Lithium Intercalation In A Porous Carbon Electrode, Gerardine G. Botte, Ralph E. White
Ralph E. White
No abstract provided.
Application Of Porous Electrode Theory On Metal Hydride Electrodes In Alkaline Solution, G. Zheng, Branko N. Popov, Ralph E. White
Application Of Porous Electrode Theory On Metal Hydride Electrodes In Alkaline Solution, G. Zheng, Branko N. Popov, Ralph E. White
Ralph E. White
Porous electrode theory was applied to estimate the exchange current density, the polarization resistance, and symmetry factor for LaNi4.27Sn0.24 hydride electrode in alkaline solution. The exchange current density, polarization resistance, and symmetry factor were determined from polarization curves which were obtained at low overpotentials.
Predicted Secondary Current Distributions For Linear Kinetics In A Modified Three-Dimensional Hull Cell, F. A. Jagush, Ralph E. White, William E. Ryan
Predicted Secondary Current Distributions For Linear Kinetics In A Modified Three-Dimensional Hull Cell, F. A. Jagush, Ralph E. White, William E. Ryan
Ralph E. White
Current density distribution is an important consideration
for those involved in designing electrochemical systems
and electroplating systems in particular. Although it
is important, the common practice in industry is to use
trial and error to determine designs that optimize current
density distributions in electroplating. The purpose of this
paper is to illustrate the use of the finite element method
(FEM) to predict three-dimensional current density distributions.
A Thermal Analysis Of A Spirally Wound Battery Using A Simple Mathematical Model, T. I. Evans, Ralph E. White
A Thermal Analysis Of A Spirally Wound Battery Using A Simple Mathematical Model, T. I. Evans, Ralph E. White
Ralph E. White
A two-dimensional thermal model for spirally wound batteries has been developed. The governing equation of the model is the energy balance. Convective and insulated boundary conditions are used, and the equations are solved using a finite element code called TOPAZ2D. The finite element mesh is generated using a preprocessor to TOPAZ2D called MAZE. The model is used to estimate temperature profiles within a spirally wound D-size cell. The model is applied to the lithium/thionyl chloride cell because of the thermal management problems that this cell exhibits. Simplified one-dimensional models are presented that can be used to predict best and worst …
Estimation Of Electrode Kinetic Parameters Of The Lithium/Thionyl Chloride Cell Using A Mathematical Model, T. I. Evans, Ralph E. White
Estimation Of Electrode Kinetic Parameters Of The Lithium/Thionyl Chloride Cell Using A Mathematical Model, T. I. Evans, Ralph E. White
Ralph E. White
A one-dimensional mathematical model for the lithium/thionyl chloride primary cell is used in conjunction with a parameter estimation technique, in order to estimate the electrode kinetic parameters of this electrochemical system. The electrode kinetic parameters include the anodic transfer coefficient and exchange current density of the lithium oxidation, a,1 and i0,1,ref; the cathodic transfer coefficient and the effective exchange current density of the thionyl chloride reduction, c,4 and a0i0,4,ref, and a morphology parameter, . The parameter estimation is performed on simulated data first in order to gain confidence in the method. Data reported in the literature for a high-rate discharge …
Simple Models For Diaphragm-Type Chlorine/Caustic Cells Ii. Effect Of Acidic Anolyte On Steady-State Caustic Yield, John Van Zee, Ralph E. White
Simple Models For Diaphragm-Type Chlorine/Caustic Cells Ii. Effect Of Acidic Anolyte On Steady-State Caustic Yield, John Van Zee, Ralph E. White
Ralph E. White
A simple steady-state model of a diaphragm-type chlorine/caustic cell in which the diaphragm is divided into two regions by a homogeneous acid-base reaction is presented. The location of the reaction affects significantly the caustic yield and effluent concentration. The model is used to predict the location of this reaction as a function of the operating variables, the physical constants, and three measurable properties of the diaphragm. These measurable properties are the MacMullin number or resistivity ratio of electrolyte-filled diaphragm relative to the electrolyte, the Darcy's law diaphragmpermeability, and the diaphragm thickness. The model is used to predict a maximum in …
A Mathematical Model Of Electrochemical Reactions Coupled With Homogeneous Chemical Reactions, Ken-Ming Yen, Taewhan Yeu, Ralph E. White
A Mathematical Model Of Electrochemical Reactions Coupled With Homogeneous Chemical Reactions, Ken-Ming Yen, Taewhan Yeu, Ralph E. White
Ralph E. White
The zinc/bromine (Zn/Br2) flow battery has received considerable
attention in recent years [e.g., (2-4)]. Although it
is agreed that the solution chemistry is important in the
system, most of the work that has been done is concentrated
on the design variables. In this note the basic mass
transfer-solution and surface kinetics are studied to furnish
a better understanding of the system.
A Comparison Of Newman's Numerical Technique And Deboor's Algorithm, D. A. Curtis, T. I. Evans, Ralph E. White
A Comparison Of Newman's Numerical Technique And Deboor's Algorithm, D. A. Curtis, T. I. Evans, Ralph E. White
Ralph E. White
Newman's numerical technique (1-4) has been used extensivelyto solve two-point boundary value problems consistingof coupled, ordinary differential equations#12;. Unfortunately,his method does not always yield a solution to asystem of independent equations#12;. Sometimes his algorithm(BAND) signals incorrectly that the coefficientmatrix is singular (e.g., DETERMINANT = 0 AT J = 2),and no solution is obtained to the system of equations#12;.This problem sometimes occurs when one tries to useBAND to solve a two-point boundary value problemwhich consists of a set of mixed order ordinary differentialequations. For example, the battery model equations presentedrecently by Evans and White (5) are representativeof this type of equation …