Abstract:
In previous meetings of the Acoustical Society of America a thermo-acoustic refrigerator model was introduced. The goal of the design was not efficiency but the possibility to apply visualization techniques such as smoke injection, thermochromatic liquid crystals, and holographic interferometry. Particularly, holographic interferometry combined with high-speed cinematography is a unique measurement technique to visualize the oscillating temperature fields in the stack region and its neighborhood of the thermoacoustic refrigerator model. Holographic measurements with a high-speed camera were taken at a frame rate of 5000 picture frames per second. Thus, for one period of oscillation (3 ms), about 16 holographic images were obtained. Applying digital image processing to the holographic images, the oscillating temperature fields can be quantified. Once these temperature fields are determined, heat fluxes and heat transfer coefficients can be calculated. Results of these experiments will be presented at the meeting. [Work supported by ONR; Martin Wetzel is also supported by a scholarship from DAAD.]