Cooling fan noise control using micro-perforates
2012 (English)In: Int. Congr. Expos. Noise Control Eng., INTER-NOISE, 2012, 10434-10445 p.Conference paper (Refereed)
Baffle or split silencers are commonly used, e.g., in HVAC systems and as inlet/outlet silencers on gas turbines. Another application is to reduce noise from the cooling fan inlet for large IC-engines. A baffle silencer can be seen as a periodic arrangement of parallel rectangular absorbers which can be placed in a rectangular duct. The noise reduction afforded by parallel baffles depends not only on the physical properties of the lining, but also upon the angle of incidence of the sound waves impinging and the baffle length. In this paper the potential of using baffles made of Micro-Perforated Panels is investigated in particular with the cooling fan inlet application in mind. Theoretical models for the damping is derived and used to design optimum configurations. The models are based on the wave propagation in a periodic array of baffles so that only one period can be investigated in order to find the different modes. In particular the least attenuated mode is important to find in order to optimize the behavior. An important aspect is the inner structure of the MPP baffle, i.e., can it just be an empty air volume or to what extent must internal waves be prevented by putting in walls. From a stiffness point of view some inner walls might also be needed to avoid vibration problems. Due to these complexities the theoretical models are only presented for the simplest cases. In order to validate the models and to get a more complete test of different designs experiments were also carried out. During these experiments the effect of flow was also tested.
Place, publisher, year, edition, pages
2012. 10434-10445 p.
, 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012, 12
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-129695ScopusID: 2-s2.0-84874619913ISBN: 9781627485609OAI: oai:DiVA.org:kth-129695DiVA: diva2:653453
41st International Congress and Exposition on Noise Control Engineering 2012
QC 201310042013-10-042013-10-032013-10-04Bibliographically approved