Apparatus for Testing Metamaterials for Reducing Noise in Ducts

A Heating Ventilation and Air Condition (HVAC) system is used to control and regulate the indoor environment of a facility. Fixtures and turbulence within the duct cause unwanted noise and can prevent an HVAC system from performing optimally. Excessive noise in HVAC ducts can become dissatisfactory for users. The purpose of this project is to design and build an experimental apparatus that can repeatedly produce a three-dimensional acoustic pressure plot in MATLAB to experimentally determine noise reduction levels of different metamaterials. The pressure plot is built by determining the frequencies at each node through a Fourier transform. Linear actuators control the three-dimensional movement of an omnidirectional microphone, while a directional speaker is used for sound wave generation through the ducts. Current results produce a two-dimensional pressure plot in a manual coding process, but a three-dimensional acoustic pressure plot can automatically be produced once a new data acquisition system is acquired.