Measurement of temperature gradient in a stack of a prime mover in a loop-tube-type thermoacoustic cooling system

This paper specifically describes spatial and temporal variation of the temperature gradient in a stack of a prime mover in a loop-tube-type thermoacoustic cooling system. Spatial and temporal variations in the temperature gradient were measured for various stack lengths. Measurements were also conducted in cases with and without self-sustained sound. Because the thermal and viscous boundary-layer thicknesses depend on the temperature, detailed knowledge of spatial and temporal variations of the temperature gradient in the stack will be important to design a stack, especially in terms of the stack channel radius. Because little has been reported about the temperature gradient formed in the stack, the results obtained in these experiments are expected to contribute to improvement of the cooling effect of thermoacoustic cooling systems. Observations of the temperature variation in cases with and without self-sustained sound in the loop-tube confirmed that with self-sustained sound, a temperature gradient is formed linearly along the stack, which resulted from the heat flow caused by the thermoacoustic effect.