FCFCT Space Engineering Institute Graduate Student Mentor: Cable Kurwitz “Monitoring Multiphase Flow in Simulated PEM Fuel Cell Under Reduced Gravity Conditions” NASA Advisor: Art Vasquez PEM Fuel Cell Team (PEMFCT) Faculty Advisor: Dr. Fred Best

Team MemberClassificationMajor Ernie EverettSeniorMEEN Nikhil BhatnagarJuniorAERO Christie TiptonJuniorBMEN Scott HansenSophomoreMEEN CaitlinRieglerFreshmanAERO Amber BoltFreshmanCHEM

 Background  Objectives  - NASA’s Needs  - SEI Goals  Test Plan  - Test Facility Design  - Ground/Flight Testing  - Microgravity University  Upcoming Activities  Conclusions

 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

 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

 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

 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: K

Serpentine Model Parallel Model

Zoomed in View 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 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

Parallel Plate Gas Used: Nitrogen Mass Flow Rate: 3 SLPM Inlet Pressure: 50 psig Inlet Temperature: K Max Channel Velocity: 0.1 m/s

Serpentine Plate Gas Used: Nitrogen Mass Flow Rate: 3 SLPM Inlet Pressure: 50 psig Inlet Temperature: K Max Channel Velocity: 0.35 m/s

Serpentine ModelParallel Model Parallel Model Delta Pressure:10 Pa Serpentine Model Delta Pressure: 56 Pa Gas Used: Nitrogen Mass Flow Rate: 3 SLPM Inlet Pressure: 50 psig Inlet Temperature: K

Specifications Power Supplied: VAC 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

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

 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

 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 Verification4. Ground Support 2. Electrical Analysis5. Hazard Analysis 3. Liquid Containment6. Emergency Procedures

 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

 - 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!

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

 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

 We would like to say thanks to our sponsors: