Fuel Cell Fluid Dynamics Topic Area: Monitoring Multiphase Flow For Microgravity Operations Team Mem

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Monitoring Multiphase Flow in Simulated PEM Fuel
Cell Under Reduced Gravity Conditions
PEM Fuel Cell Team (PEMFCT)
Graduate Student Mentor Cable Kurwitz
Faculty Advisor Dr. Fred Best
NASA Advisor Art Vasquez
FCFCT
Space Engineering Institute 2008-2009
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Team Members
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Presentation Outline

• Background
• Objectives
• - NASAs Needs
• - SEI Goals
• Test Plan
• - Test Facility Design
• - Ground/Flight Testing
• - Microgravity University
• Upcoming Activities
• Conclusions

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What is a Fuel Cell?

• Typical fuel cells generate electricity by
  combining a fuel and oxidizer in the presence of
  an electrolyte
• Main parts of a fuel cell
• Flow channels for fuel and oxidizer
• Anode and Cathode separated by an electrolyte
• Proton Exchange Membrane (PEM)
• Fuel and oxidizer react to produce electricity
  and byproducts
• Currently cells are about 40-60 efficient
• Goal Increase Efficiency

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Problem - Fluid Instabilities

• There is a need for a better understanding of
  multi-phase flow within cell plates of fuel cells
• Instabilities are produced by flow regime
  transitions brought on by the production of water
  within the fuel cell
• - Instability caused by liquid occlusions or
  slugs leads to unsteady fuel cell currents and
  reduces efficiency

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Objectives

• NASAs Need
• - Utilized fuel cells in Gemini, Apollo, and
  currently in Space Shuttle
• - NASA plans to utilize fuel cells in
  Constellation program
• - Technology has many other applications
• Vehicles, buildings, and alternative energy
  applications
• Purpose
• -Evaluate flow conditions within a prototypic
  fuel cell geometry
• - Determine a range of stable operations for
  given flow and environmental conditions
• - Stable operation will lead to increased fuel
  cell efficiency
• Learning Objectives
• - Understand fluid flow within fuel cells
• - Identify and understand the flow conditions
  that produce instabilities

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Prototypic Fuel Cell

• Proposed Design
• -Cell geometries and dimensions
• Based on typical fuel cell producing 1kW using 45
  cell plates
• Typical channel dimension from 0.8 to 1.4 mm2
• Wetted surface area are equal on all plates
• Acrylic was chosen to allow visualization and
  easier analysis
• Will need to experiment for optimal water
  insertion method
• Flow Conditions
• Gas Nitrogen due to its inertness
• Mass flow rate 0-5 SLPM
• Inlet Pressure 50 psig
• Temperature 292.3 K

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Cell Plate Designs
Serpentine Model
Parallel Model
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Parallel Plate
Dimensions 20 cm x 20 cm x 1 cm Channel
Dimensions 1 mm x 1mm Number of Channels 80
Wetted Surface Area 10,700 mm3
Zoomed in View
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Serpentine Plate
Dimensions 20 cm x 20 cm x 1 cm Channel
Dimensions 1 mm x 1mm Number of Channels 20
Wetted Surface Area 10,700 mm3
Zoomed in View
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Cosmos FloWorks Velocity Analysis
Parallel Plate Gas Used Nitrogen Mass Flow
Rate 3 SLPM Inlet Pressure 50 psig Inlet
Temperature 293.2 K Max Channel Velocity 0.1
m/s
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Cosmos FloWorks Velocity Analysis
Serpentine Plate Gas Used Nitrogen Mass Flow
Rate 3 SLPM Inlet Pressure 50 psig Inlet
Temperature 293.2 K Max Channel Velocity
0.35 m/s
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Cosmos FloWorks Pressure Analysis
Serpentine Model
Parallel Model
Gas Used Nitrogen Mass Flow Rate 3
SLPM Inlet Pressure 50 psig Inlet Temperature
293.2 K
Parallel Model Delta Pressure 10 Pa Serpentine
Model Delta Pressure 56 Pa
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Electrical Diagram

• Specifications
• Power Supplied
• 120 VAC 60 Hz _at_ 20 Amps Max
• Electronics
• - Uninterruptible power supply
• - DC Power Supply Converter
• - Laptop
• Digital to Analog Converter (DAQ)
• Sensors
• 1 x Accelerometer
• 1 x Thermocouple
• 1 x Pressure Indicator
• 2 x Pressure Transducer
• 2 x Mass Flow Controller
• - Mass Flow
• - Pressure
• - Temperature
• - Volume

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Flow Loop Schematic
Flow Loop Schematic

• Specifications
• Gas provided by high pressure Nitrogen Tank
• Regulated to 50 psig
• Pressure Transducer will monitor pressure drop
• Parallel Mass flow meters will simulate excess
  cells
• CCD Digital Camcorders will record fluid
  instabilities
• Vortex Water Separator will separate fluid from
  gas

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Microgravity University - Reduced Gravity
Student Flight Opportunities Program

• Allows undergraduate teams to carryout flight
  testing of experiments in zero-g conditions
• - Proposal
• - Safety Analysis
• - Funding
• - Education Outreach
• Flies a series of 32 parabolas to give occupants
  about 25 seconds of freefall
• 30 Zero-g
• 1 Lunar Gravity
• 1 Martian Gravity

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Design and Construction of Test Package
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Safety

• Guidelines Set Forth by NASA
• - Experiment Design Requirements Guidelines 932
  C-9B
• - Interface Control Document 932 C-9B
• Project Safety Evaluation
• - Experiment Safety Evaluation (Submitted)
• - Test Equipment Data package (In-Progress)
• Standard Operating Procedure (SOP)

1. Structural Verification 4. Ground Support 2.
Electrical Analysis 5. Hazard Analysis 3. Liquid
Containment 6. Emergency Procedures
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Education Outreach

• Exhibition of flight experiment at Dallas Museum
  of Nature and Science
• Reduced Gravity Flight Challenge
• Working with Middle School Educators to form
  three teams of sixth grade students
• Students will design an experiment to fly in
  conjunction with our experiment
• SEI Outreach Events
• Space Vision 2008, Paschal HS, Roosevelt HS
• Website/Videos

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Learning Experiences

• - Engineering Skills
• Analysis Tools
• Solid Works, Cosmos FloWorks, CosmosWorks,
  Microsoft Vizio
• Analytic techniques to validate computation
• Analysis of test data (i.e. model fitting)
• Lab Skills
• Machining experience
• Interpreting engineering drawings
• Developing procedures
• Carrying out test
• Education Outreach
• Teamwork
• Movie!

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Upcoming Activities

• Fabricate flow facility
• Carryout ground testing
• Prepare for microgravity flight
• Safety documentation
• Analyze data
• Prepare final report

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Conclusion / Results

• Purpose
• -Evaluate flow conditions within a prototypic
  fuel cell geometry
• - Determine a range of stable operations for
  given flow and environmental conditions
• Conducting Ground and Flight Tests

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Comment and Question?

• We would like to say thanks to our sponsors