A miniature, broadband acoustic spectrometer : design of a unified attenuation model, device development, and experimental performance

The attenuation of sound occurs in polyatomic gases due to both classical and nonclassical physics. Classical attenuation is dominated by viscous dissipation and irreversible heat conduction. Nonclassical attenuation arises from the thermal relaxation between internal and external degrees of freedom for each constituent molecule. Currently, we are not aware of any commercial gas sensors that leverage classical attenuation. Existing methods to detect gas composition using nonclassical attenuation are bulky, heavy, and slow at resolving measurements, as the instruments utilize highly resonant, single frequency transducers mounted within rigid containment vessels that are pressurized sequentially over a wide range of pressures. We leverage both classical and nonclassical attenuation to develop a miniature, broadband acoustic spectrometer capable of detecting gas composition. This thesis covers modeling, design, and experimental efforts.

Name thesis:degree_name

Doctoral

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2019

Author dc:creator

• Demas, Nickolas Peter.

Advisor dc:contributor.advisor

• Ian W. Hunter.

• Mechanical Engineering.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1721.1/122511

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/122511