Noise Reduction of Air Distribution Grilles Using 3D Printed Infill Structures

The aim of this research is to reduce the noise level of air distribution grilles using 3D printed infill structures. The grilles are installed on a newly developed autonomous ventilation system, which is used for decentralised ventilation of e.g., school classrooms. Several supply and return grilles with functional gyroid and honeycomb shaped infill structures were created and subsequently printed on an FDM 3D printer. Based on measurements and analysis of the maximum sound pressure levels at different microphone positions around the system and at different airflows, the combination of grilles with the greatest noise reduction was selected. The research is complemented by other data such as spectral analysis of the noise, measurement of the airflow velocity through the grilles and measurement of the room reverberation time. Significant noise reduction was achieved by using the proposed grilles and further conclusions were drawn. 3D printing technology proved to be a very useful tool in this case.