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Stephen Wolf

Stephen Wolf

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Stephen Wolf

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  1. Chemically driven carbon-nanotubeguided thermopower waves Stephen Wolf

  2. Basic Idea • External chemical combustion around a MWNT • Anistropic thermal conductivity causes an acceleration of the reaction wave • Various effects upon associated effects, such as enhanced thermopower generation and propulsion.

  3. Synthesis • MWNT with a 7nm thick cyclotrimethylenetrinitramine (TNA, combustible element) coating • MWNT created with CVD • Wet impregnation of TNA

  4. Ignition and Reaction • TNA ignited with a laser or electrical discharge • Sustained reaction rates at 4-10 times bulk TNA reaction • Alignment critical to the process, no effect displayed at all with random alignments confirms the MWNT is the amplifier

  5. Graphs of reaction velocities (measured a,b) and theoretical(c)

  6. Thermopower Wave • This reaction wave and thermal gradient creates power by the Seebeck effect.

  7. Different compared to normal effect, or seebeck effect with slower waves Higher mass and center ignition Accelerated Waves

  8. Very high specific power • Specific power (energy per mass unit) was very high, comparable or greater than Li-ion depending on sample • Increasing specific power with smaller mass

  9. Smaller losses with smaller mass • A larger array allows for more orthogonal heat propagation • The orthogonal propagation is not as fast as the axial, more losses occur

  10. Pressure Waves • This reaction also creates very high pressure waves and can be used to create a microthruster with much higher figures of merit than others currently available

  11. Conclusion • High anistropic thermal conductivity in the CNT allows for guided, accelerated thermal reaction waves • These reaction waves lead to correspondingly unique pressure and thermopower waves • Applications for single use power supplies and microthrusters

  12. Questions?