Type of Document	Master's Thesis
Author	Sesler, Josh J
Author's Email Address	joshsesler@gmail.com
URN	etd-10212005-015333
Title	Implementation of Refractory Foam Technology for Silencing Small IC Engines
Degree	Master of Science
Department	Mechanical Engineering
Advisory Committee	Advisor Name Title Burdisso, Ricardo A. Committee Chair Saunders, William R. Committee Co-Chair Fleming, Jon Committee Member
Keywords	Refractory foam Sound absorption Absorptive material Dissipative muffler Silencer
Date of Defense	2005-09-09
Availability	unrestricted
Abstract 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.
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