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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. Team Members.
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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
Presentation Outline • Background • Objectives • - NASA’s Needs • - SEI Goals • Test Plan • - Test Facility Design • - Ground/Flight Testing • - Microgravity University • Upcoming Activities • Conclusions
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
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
Objectives • NASA’s 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
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 mm^2 • 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
Cell Plate Designs Serpentine Model Parallel Model
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 mm^3 Zoomed in View
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 mm^3 Zoomed in View
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
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
Cosmos FloWorks Pressure Analysis Parallel Model Serpentine 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
Electrical Diagram • Specifications • Power Supplied: • 120 VAC 60 Hz @ 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 • 2 x Mass Flow Meter • 2 x CCD Digital Camcorder • 2 x Syringe Pump • Vortex Water Separator Pump
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
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
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
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
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!
Upcoming Activities • Fabricate flow facility • Carryout ground testing • Prepare for microgravity flight • Safety documentation • Analyze data • Prepare final report
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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