粒子成像测速(PIV)法测量热声制冷器板叠中的声速
Thermoacoustic refrigeration systems generate cooling power from a high-amplitude acousticstanding wave. There has recently been a growing interest in this technology because of its simple androbust architecture and its use of environmentally safe gases. With the prospect of commercialization,it is necessary to enhance the efficiency of thermoacoustic cooling systems and more particularly ofsome of their components such as the heat exchangers. The characterization of the flow field at theend of the stack plates is a crucial step for the understanding and optimization of heat transfer betweenthe stack and the heat exchangers. In this study, a specific Particle Image Velocimetry measurement(PIV) isperformed inside a thermoacoustic refrigerator. Acoustic velocity is measured using synchronizationand phase-averaging. The measurement method is validated inside a void resonator by successfullycomparing experimental data with an acoustic plane wave model. Velocity is measured inside theoscillating boundary layers, between the plates of the stack, and compared to a linear model. Theflow behind the stack is characterized, and it shows the generation of symmetric pairs of counterrotatingvortices at the end of the stack plates at low acoustic pressure level. As the acoustic pressurelevel increases, detachment of the vortices and symmetry breaking are observed.