Implementation of Refractory Foam Technology for Silencing Small IC Engines

With the need for stealth in defense applications steadily increasing, noise reduction continues to play an important role in the world of aeronautics. With the ever increasing number of small UAV flight vehicle designs and their stringent weight requirements, acoustic solutions become progressively more complex. This thesis investigates the use of refractory foam, a new class of porous material, for designing effective silencers for small IC engines. The solution must be lightweight, compact, conformable, and capable of handling the rigors of flight. Throughout the course of this research, many silencer designs were fabricated to take advantage of refractory foam technology. These silencer designs were then tested against existing designs using both anechoic and outdoor testing techniques. These results proved refractory foam to be a superior broadband noise absorber that can survive harsh flight environment. Silencer designs using this material showed overall improvements in the areas of noise reduction, weight, size, and backpressure, compared to commercial designs. The final silencer design boasted an Aweighted overall sound pressure level that was 12.1 dBA lower than the reference case. This result was accomplished using nearly half the volume required by other designs to attain similar results.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2005

Author dc:creator

• Sesler, Josh J.

Chairs dc:contributor.committeechair

• Burdisso, Ricardo A.
• Saunders, William R.

Committee member dc:contributor.committeemember

• Fleming, Jon

• Refractory foam
• Sound absorption
• Absorptive material
• Dissipative muffler
• Silencer

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-10212005-015333

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/35453