Development of an Experimental Facility Towards Sound Excitation Effects on Forced Convection Heat Transfer

In light of the potential of acoustic excitation for heat transfer enhancement, the research effort herein is geared towards a better understanding of the underlying physical mechanisms of aero-thermal laminar and turbulent boundary layer development under the influence of directed sound excitation. An experimental measurement campaign is carried out throughout which the effects of small amplitude periodic flow oscillations on convective heat transfer in straight channels are investigated. A low velocity wind tunnel facility has been designed and built for this purpose. Measurements of convective heat transfer are conducted by means of steady wide band liquid crystal thermometry at several acoustic and aerodynamic parameters. The findings of this investigation indicate that modification of convective heat transfer by directed sound excitations is possible. Dependent on the source frequency, the net effect can be a heat transfer augmentation or a local reduction. Although the acoustically induced changes are small in magnitude, the dependence on the excitation frequency is still quantifiable beyond measurement error.