FCFCTSpace Engineering Institute

2008-2009

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 Member Classification Major

Ernie Everett Senior MEEN

Nikhil Bhatnagar Junior AERO

Christie Tipton Junior BMEN

Scott Hansen Sophomore MEEN

CaitlinRiegler Freshman AERO

Amber Bolt Freshman CHEM

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: 292.3 K

Serpentine Model

Parallel Model

Zoomed in View

Dimensions: 20 cm x 20 cm x 1 cmChannel Dimensions: 1 mm x 1mmNumber of Channels: 80 Wetted Surface Area: 10,700 mm^3

Zoomed in View

Dimensions: 20 cm x 20 cm x 1 cmChannel Dimensions: 1 mm x 1mmNumber of Channels: 20 Wetted Surface Area: 10,700 mm^3

Parallel PlateGas Used: NitrogenMass Flow Rate: 3 SLPMInlet Pressure: 50 psigInlet Temperature: 293.2 KMax Channel Velocity: 0.1 m/s

Serpentine PlateGas Used: NitrogenMass Flow Rate: 3 SLPMInlet Pressure: 50 psigInlet Temperature: 293.2 KMax Channel Velocity: 0.35 m/s

Serpentine ModelParallel Model

Parallel Model Delta Pressure: 10 Pa Serpentine Model Delta Pressure: 56 Pa

Gas Used: NitrogenMass Flow Rate: 3 SLPMInlet Pressure: 50 psigInlet Temperature: 293.2 K

SpecificationsPower 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 Accelerometer1 x Thermocouple1 x Pressure Indicator2 x Pressure Transducer2 x Mass Flow Controller - Mass Flow - Pressure - Temperature - Volume

2 x Mass Flow Meter2 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 Verification 4. Ground Support2. Electrical Analysis 5. Hazard Analysis3. Liquid Containment 6. 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

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