Numerical Modeling of Two-Phase Flow in a Bipolar Plate of a PEM Electrolyzer Cell

2008 ◽  
Author(s):  
Jianhu Nie ◽  
Yitung Chen ◽  
Robert F. Boehm
Keyword(s):  
Distribution System ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Bipolar Plate ◽  
Electrolysis Cell ◽  
Low Velocity ◽  
Two Phase ◽  
Bubble Generation ◽  
Oxygen Bubble

Optimization of electrolysis cell for producing hydrogen is dependent of a set of complex physical and chemical processes simultaneously occurring within the electrolysis cell. Similar to fuel cells, it has been demonstrated that these processes are strongly dependent on the fluid dynamics inside the electrolysis & fuel cell. Bipolar plates are important components of PEM electrolysis cells because they are the first stage of the flow distribution system. Numerical simulations were performed for three-dimensional two-phase water/oxygen flow in the anode side of a bipolar plate with a diagonal flow design. The water flowrate was maintained as constant of 260 ml/min, while the oxygen bubble generation rate was assumed to change from 0–0.014 g/s. Numerical results reveal that a minimum of the peak values of mainstream velocity component in the channels develops in the middle of the plate. Pressure drop and volume fraction of oxygen at the exit become higher as the oxygen bubble generation flowrate increases. The irregular velocity profile (locally low velocity magnitude near the exit port section) is not observed when the oxygen bubble flowrate is relatively low.

Numerical Modeling of Velocity and Temperature Distributions in a Bipolar Plate of PEM Electrolysis Cell With Greatly Improved Flow Uniformity

2009 ◽  
Author(s):  
Jephanya Kasukurthi ◽  
K. M. Veepuri ◽  
Jianhu Nie ◽  
Yitung Chen
Keyword(s):  
Heat Transfer ◽  
Proton Exchange Membrane ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Bipolar Plate ◽  
Proton Exchange ◽  
Electrolysis Cell ◽  
Flow And Heat Transfer ◽  
Temperature Distributions ◽  
Pem Electrolysis

In this present work, finite volume method was used to simulate the three-dimensional water flow and heat transfer in a flow field plate of the proton exchange membrane (PEM) electrolysis cell. The standard k-ε model together with standard wall function method was used to model three-dimensional fluid flow and heat transfer. First, numerical simulations were performed for a basic bipolar plate and it was found that the flow distribution inside the channels in not uniform. The design of the basic bipolar plate has been changed to a new model, which is featured with multiple inlets and multiple outlets. Numerical results show that the flow and temperature distributions for the new design become much homogeneous.

A New Bipolar Plate of PEM Electrolysis Cell With Uniform Flow and Heat Transfer Fields

2008 ◽  
Author(s):  
J. H. Nie ◽  
K. M. Veepuri ◽  
Y. T. Chen ◽  
J. F. Wu
Keyword(s):  
Distribution System ◽  
Flow Distribution ◽  
Water Electrolysis ◽  
Bipolar Plate ◽  
Uniform Flow ◽  
Cfd Modeling ◽  
Electrolysis Cell ◽  
Uniform Flow Distribution ◽  
Pem Electrolysis ◽  
Physical And Chemical

Optimization of electrolysis cell for producing hydrogen is dependent of a set of complex physical and chemical processes occurring simultaneously. Similar to fuel cells, it has been demonstrated that these processes are strongly dependent on the fluid dynamics inside the fuel cell. Bipolar plates are important components of PEM electrolysis cells because they are the first stage of the flow distribution system. A non-uniform flow distribution across the bipolar plate surface area will probably lead to an unbalanced use of the precious catalyst, and an overall efficiency of the device lower than expected. In the present work a new design of bipolar plate for the PEM electrolysis cell was proposed and 3-D CFD modeling was preformed. Velocity, temperature and pressure distributions within the bipolar plate were investigated. Numerical simulations showed that the flow uniformity within the designed bipolar plate is greatly improved compared with the baseline bipolar plate for water electrolysis.

Explorations of Improving Flow Uniformity in the Bipolar Plate of a PEM Electrolysis Cell Using Different Designs

2008 ◽  
Author(s):  
J. H. Nie ◽  
Y. T. Chen ◽  
J. F. Wu ◽  
K. M. Veepuri
Keyword(s):  
Distribution System ◽  
Hydrogen Generation ◽  
Flow Distribution ◽  
Water Electrolysis ◽  
Bipolar Plate ◽  
Electrolysis Cell ◽  
Flow Uniformity ◽  
Uniform Flow Distribution ◽  
Pem Electrolysis ◽  
Physical And Chemical

Optimization of electrolysis cell for producing hydrogen is dependent of a set of complex physical and chemical processes occurring simultaneously. Similar to fuel cells, it has been demonstrated that these processes are strongly dependent on the fluid dynamics inside the fuel cell. Bipolar plates are important components of PEM electrolysis cells because they are the first stage of the flow distribution system. A non-uniform flow distribution across the bipolar plate surface area will probably lead to an unbalanced use of the precious catalyst, and an overall efficiency of the device lower than expected. In the present work various concepts were tested for the purpose of improving flow uniformity in the bipolar plate of a PEM electrolysis cell for hydrogen generation. Numerical results including pressure distributions and velocity profiles are reported. It is shown that the flow uniformity within the designed bipolar plate is greatly improved compared with the baseline bipolar plate for water electrolysis.

Transient Analysis of Nonuniform Heat Input Propagation Through a Heat Sink Base

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Srivathsan Sudhakar ◽  
Justin A. Weibel
Keyword(s):  
Heat Source ◽  
Heat Input ◽  
Heat Sink ◽  
Three Dimensional ◽  
Temperature Response ◽  
Flow Distribution ◽  
Temporal Variations ◽  
Step Response ◽  
Dimensional System ◽  
Two Phase

For thermal management architectures wherein the heat sink is embedded close to a dynamic heat source, nonuniformities may propagate through the heat sink base to the coolant. Available transient models predict the effective heat spreading resistance to calculate chip temperature rise, or simplify to a representative axisymmetric geometry. The coolant-side temperature response is seldom considered, despite the potential influence on flow distribution and stability in two-phase microchannel heat sinks. This study solves three-dimensional transient heat conduction in a Cartesian chip-on-substrate geometry to predict spatial and temporal variations of temperature on the coolant side. The solution for the unit step response of the three-dimensional system is extended to any arbitrary temporal heat input using Duhamel's method. For time-periodic heat inputs, the steady-periodic solution is calculated using the method of complex temperature. As an example case, the solution of the coolant-side temperature response in the presence of different transient heat inputs from multiple heat sources is demonstrated. To represent a case where the thermal spreading from a heat source is localized, the problem is simplified to a single heat source at the center of the domain. Metrics are developed to quantify the degree of spatial and temporal nonuniformity in the coolant-side temperature profiles. These nonuniformities are mapped as a function of nondimensional geometric parameters and boundary conditions. Several case studies are presented to demonstrate the utility of such maps.

Droplet Formation in a Microchannel T-Junction With Different Step Structure Position

2020 ◽  
Vol 143 (7) ◽  
Author(s):  
Mohammad Yaghoub Abdollahzadeh Jamalabadi ◽  
Rasoul Kazemi ◽  
Mohammad Ghalandari
Keyword(s):  
Nusselt Number ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Droplet Formation ◽  
Continuous Phase ◽  
Flow Path ◽  
The Other ◽  
Two Phase ◽  
Fluid Behavior ◽  
Discrete Phase

Abstract In this study, numerical simulation of formation of droplet within T-shaped microchannel is investigated. Three-dimensional, transient and two-phase numerical solution for four different microchannels with different stepping positions in the flow path was performed. Various parameters such as volume fraction, Nusselt number, pressure, Reynolds number, and temperature are discussed. The results show that the location of stepped barriers in the flow path affects the process of droplet formation, its number and size in the microchannel and should be considered as an important factor in determining the fluid behavior in the microchannel. It was observed that by placing half of the step at the entrance and the other half after the entrance, the continuous phase (S3 mode) was formed in 37.5 s compared to the other modes. The droplets were also smaller in size and more in numbers. It was also observed that the maximum value for the Nusselt number was obtained for the S2 mode where the step was located just above the discrete-phase entrance. In addition, the pressure at the inlet was higher and the flow velocity increased after the step and its pressure decreased, and continued to decrease due to frictional path.

Vortex Simulation for Behavior of Solid Particles Falling in Air

2011 ◽  
Author(s):  
Hisanori Yagami ◽  
Tomomi Uchiyama
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Air Flow ◽  
Three Dimensional ◽  
Particle Diameter ◽  
Vortex Method ◽  
Solid Particles ◽  
Particle Volume ◽  
Two Phase ◽  
Spherical Region

The behavior of small solid particles falling in an unbounded air is simulated. The particles, initially arranged within a spherical region in a quiescent air, are made to fall, and their fall induces the air flow around them, resulting in the gas-particle two-phase flow. The particle diameter and density are 1 mm and 7.7 kg/m3 respectively. A three-dimensional vortex method proposed by one of the authors is applied. The simulation demonstrates that the particles are accelerated by the induced downward air flow just after the commencement of their fall. It also highlights that the particles are whirled up by a vortex ring produced around the downward air flow after the acceleration. The effect of the particle volume fraction at the commencement of the fall is also explored.

The 3-D Finite Element Analysis on Elastic-Plastic Micromechanical Response of the Particle Volume Fraction

2019 ◽  
Vol 962 ◽  
pp. 210-217
Author(s):  
Yong Ming Guo ◽  
Nozomi Fukae
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Three Dimensional ◽  
Particle Volume ◽  
Two Phase ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Microstructural Parameters ◽  
Commercial Software Package ◽  
Properties Of Materials

It is well known that the properties of materials are a function of their microstructural parameters. The FEM is a good selection for studies of three-dimensional microstructure-property relationships. In this research, the elastic-plastic micromechanical response of the particle volume fraction of two-phase materials have been calculated using a commercial software package of the FEM, some new knowledges on the microstructure-property relationships have obtained.

Numerical Simulation of Black Liquor Spray Characteristics

2002 ◽  
Author(s):  
Thomas D. Foust ◽  
Kurt D. Hamman ◽  
Brent A. Detering
Keyword(s):  
Droplet Size ◽  
Volume Fraction ◽  
Numerical Study ◽  
Black Liquor ◽  
Flow Distribution ◽  
Physical Models ◽  
Spray Characteristics ◽  
Two Phase ◽  
Vof Model ◽  
Sheet Breakup

The performance and capacity of Kraft recovery boilers is sensitive to black liquor velocity, droplet size and flow distribution in the furnace. Studies have shown that controlling droplet size and flow distribution improves boiler efficiency while allowing increased flight drying and devolatilization, and decreased carryover. The purpose of this study is to develop a robust two-phase numerical model to predict black liquor splashplate nozzle spray characteristics. A three-dimensional time dependent numerical study of black liquor sheet formation and sheet breakup is described. The volume of fluid (VOF) model is used to simulate flow through the splashplate nozzle up to initial sheet breakup and droplet formation. The VOF model solves the conservation equations of volume fraction and momentum utilizing the finite volume technique. Black liquor velocity, droplet size and flow distribution over a range of operating parameters are simulated using scaled physical models of splashplate nozzles. The VOF model is compared to results from a flow visualization experiment and experimental data found in the literature. The details of the simulation and experimental results are presented.

Non-Uniform Velocity Distributions in Bipolar Plate PEM Electrolysis Cell

2007 ◽  
Author(s):  
Jianhu Nie ◽  
Yitung Chen ◽  
Steve Cohen ◽  
Blake Carter ◽  
Robert F. Boehm
Keyword(s):  
Velocity Component ◽  
Numerical Models ◽  
Three Dimensional ◽  
Bipolar Plate ◽  
Electrolysis Cell ◽  
Pressure Drops ◽  
Exit Tube ◽  
Inlet Tube ◽  
Pem Electrolysis ◽  
A Minor

The rate of hydrogen production within the PEM electrolysis cell is influenced by the temperature, the velocity distributions, and the pressure distribution. In order to design and use a PEM electrolyzer cell effectively, analytical and/or numerical models for the device are necessary so that the system may be optimized. Numerical simulations of three-dimensional water flow were performed for the purpose of examining pressure and velocity distributions in the bipolar plate of a simplified PEM electrolysis cell. The flow range in the present study is assumed to be hydrodynamically stable and steady. The numerical results show that the pressure drops diagonally from the inlet tube to the exit tube. The velocity distribution is very non-uniform in the channels. A minimum of the peak values of mainstream velocity component in the channels develops in the middle of the plate. The maximum of these peak values appears in the channel near the exit tube. The lines along which the mainstream velocity component is a peak in the channel almost overlay with each other, except that a minor difference can be noticed in the channel near the exit tube.

Numerical Analysis of Erosive Wear on the Guide Vanes of a Francis Turbine

2015 ◽  
Vol 741 ◽  
pp. 531-535
Author(s):  
Hong Ming Zhang ◽  
Li Xiang Zhang
Keyword(s):  
Numerical Analysis ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Erosive Wear ◽  
Francis Turbine ◽  
Two Phase ◽  
Guide Vanes ◽  
Flow Equations ◽  
Sand Erosion ◽  
Volume Method

The paper presents the numerical analysis of erosive wear on the guide vanes of a Francis turbine using CFD code. The 3-D turbulent particulate-liquid two-phase flow equations are employed in this study. The computing domain is discretized with a full three-dimensional mesh system of unstructured tetrahedral shapes. The finite volume method is used to solve the governing equations and the pressure-velocity coupling is handled via a Pressure Implicit with Splitting of Operators (PISO) procedure. Simulation results have shown that the volume fraction of sand at the top of the guide vanes is higher than others and the maximum of volume fraction of sand is at same location with the maximum of sand erosion rate density. The erosive wear is more serious at the top of the guide vanes.

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