COMSOL Model of an Enclosed Coaxial Carbon Nanotube (CNT) Speaker with Perforate Analysis

Carbon nanotube (CNT) speakers are thin film, flexible, light weight, and acoustically transparent that operate on the thermoacoustic principle. Rapid oscillations in the surface temperature result in density variations in the surrounding medium resulting in generation of pressure waves or sound. High operating temperatures, light weight and flexibility to conform to any shape makes them suitable for active exhaust noise cancellation in automobiles. Previous work was done to simulate an enclosed coaxial CNT speaker using COMSOL Multiphysics using a 2D axisymmetric model. The simulated sound pressure values were compared with the measured values to validate the model. This paper builds on the previous work by simulating a 3D model of the coaxial speaker in COMSOL Multiphysics. 3D model allows better modeling of flow and thermal behavior of the coaxial CNT speaker. Comparison is made between the measured and simulated sound pressure levels. Along with this, CFD analysis of perforate pattern on the speaker pipe is also discussed.