Modeling and experimental demonstration of heat flux driven noise cancellation on source boundary

This theoretically supplemented experimental research effort is devoted towards demonstrating the feasibility of using heat flux driven transducers, in order to annihilate undesirable acoustic fields directly at the source boundary. Using commonly available materials, a thermophone is produced and deposited on a conventional vibro-acoustic loudspeaker. Unifying the sound energy input from heat and work related processes, a holistic model is derived from first law of thermodynamics - simulating pressure fields at different locations. In the case of thermo-acoustic sound production, the formulation is complemented by an efficiency model based on Fourier heat conduction in a slab with internal unsteady generation. The ensuing sound pressure level emanating from the two sources is predicted for a broad range of measurement locations and relative excitation phase angles. The theoretical estimates are corroborated by experimental results under different conditions. For the prescribed experimental parameters, a heat-flux transducer is shown to successfully diminish the pressure wave generated by a conventional loudspeaker to ambient noise levels.