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Experimental and Theoritical Study of Thermo-acoustic Effect in Carbon Nanotubes

Asadzadeh, Saeed | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46425 (05)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Moosavi, Ali
  7. Abstract:
  8. Carbon Nanotube webs exhibit interesting properties when used as thermo-acoustic projectors. This work studies thermo-acoustic phenomena of these sound sources both in near and far field regions. Our three-dimensional simulation and experimental data show pressure waves are highly affected by dimensions of sound sources in near field due to interference effects. Although pressure amplitude increases with increasing frequencies, maximum pressure amplitude reached in lower frequencies may become larger than its maximum amount at higher frequencies because of interference effects. Measurement of different surface area sources shows generation of sound waves in far field is independent of projectors area surface. Based on two alternative forms of energy equation, we have developed two straightforward 1-D equations for pressure field both in open and closed systems which are consistent with experimental data. Efficiency analysis of closed system indicates that the use of large area plates with minimum possible space between them could improve efficiency in encapsulated projectors. Looking further for increasing efficiency in closed systems, herein we present a method by taking advantages of using high frequencies to stimulate plates at lower resonance frequencies. This method not only decreases energy consuming by sound sources- hence improves its performance-, but also results in a considerable lower temperature of these encapsulated projectors in which high temperature used to be a barrier for reaching high sound pressures
  9. Keywords:
  10. Sound ; Carbon Nanotubes ; Ultrasonic Waves ; Thermoacoustic Effect

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