Tribology -case study

Self-replenishing, Self-repairing Solid Lubrication Technology for Fuel Cells : 

Self-replenishing, Self-repairing Solid Lubrication Technology for Fuel Cells Emmanuel Y.A. Wornyoh and C. Fred Higgs III Particle Flow and Tribology Laboratory Mechanical Engineering Dowd/ICES Seminar October 21, 2005

Outline of Presentation : 

Outline of Presentation Need for new compressor technology in fuel cells Oil-free, self-replenishing lubrication Proposed Research: Developing oil-free, self-replenishing lubrication for compressor

Mobile Fuel Cell (FC) Power Systems : 

Mobile Fuel Cell (FC) Power Systems Benefits of Fuel Cell Compressors: Increased fuel efficiency Increased power density Reduced stack size Reduced cost Fuel Cell Automobile* *Daimler-Chrysler **http://www.mechanology.com Needs of Fuel Cell Compressors: More powerful positive-pressures Extreme rotational speeds (~160 mph) Oil-free lubrication

Lubrication Mechanism for Fuel Cell Compressor : 

Lubrication Mechanism for Fuel Cell Compressor Motivation Energy efficiency Replacing oil lubricants with powder lubricants Freeing depleting global oil supplies Environmental concerns Testing “green” lubricants Tribological Advantages Stability, sustainability in extreme environments (-100 oC to ~800 oC) Fuel Cell Compressor (Courtesy Mechanology,LLC) Journal Bearing

Slide 5: 

Problem Statement Need for a novel lubrication system for fuel cell compressors Oil-free lubrication to avoid fuel cell stacks contamination Lubrication must be adequate at extreme speeds (~160mph) and high loads Proposed Method Design and construction of tribometer Conduct experiments Development of the powder lubrication (CVFC) model Predicts tribological parameters (e.g., friction and wear)

Film Transfer Experiments: Pellet-On Disk with Slider : 

Film Transfer Experiments: Pellet-On Disk with Slider Higgs III, C.F., Ph.D Thesis, Rensselaer Polytechnic Institute, 2001 Kaur, Higgs, and Heshmat, STLE Tribology Transactions, 2001 Measurables 1) Pad friction 2) Pellet friction 3) Pellet Wear

Past Powder Results: Friction and wear versus slider contact pressure : 

Past Powder Results: Friction and wear versus slider contact pressure Deposition rate (cm3cm-1kg-1) Friction coefficient

Proposed Research : 

Proposed Research Experimentation Modeling

Experimentation: Pellet-On Disk with Slider Tribometer : 

Experimentation: Pellet-On Disk with Slider Tribometer Measurables: Pad friction Pellet friction Pellet wear

Experimentation: Pellet-On Disk with Slider Tribometer(in construction) : 

Experimentation: Pellet-On Disk with Slider Tribometer(in construction) Tribometer (Photograph) (Boric acid powder )

Control Volume Fractional Coverage (CVFC) Model : 

Control Volume Fractional Coverage (CVFC) Model Wornyoh, E.Y.A., & Higgs, C.F., III, Proceedings of World Tribology Congress III, 2005

Solving the CVFC Model : 

Solving the CVFC Model Time Constant

Adopting the Linear Rule of Mixtures : 

Adopting the Linear Rule of Mixtures Dickrell, P.L., Sawyer, W.G., and Erdemir, A., Journal of Tribology, 2004

Current and Proposed Research : 

Current and Proposed Research Construction of tribometer Pellet-on-disk with slider experiments Powder lubrication modeling

Acknowledgements : 

Acknowledgements The Dowd/ICES PhD fund at CMU The Pennsylvania Infrastructure for Technological Innovation (PITA) Mechanical Engineering Machine Shop Members of the Particle Flow & Tribology Laboratory