Fan Noise Control Using Microperforated Splitter Silencers

Splitter or baffle silencers are commonly used, for example, in heating ventilation and air conditioning (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 splitter 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 splitters depends not only on the physical properties of the lining but also upon the angle of incidence of the impinging sound waves, and the splitter and duct dimensions. In this paper, the potential of using splitters made of microperforated plates (MPPs) is investigated, with a particular focus on cooling fan inlet/outlet applications.