On Some Nonlinear Effects of Heat Transport in Thermal Buffer Tubes

Thermal buffer tubes and pulse tubes, elements of thermoacoustic systems, should thermally isolate their two ends at substantially different temperatures while acoustic power freely flows from end to end. In practical high‐power operating regimes of thermoacoustic devices, large heat leaks due to acoustic streaming can appear along a thermal buffer tube, which may degrade the overall system performance. To study this effect, a controlled experimental system is under development that will allow measurements of the heat leak due to acoustic streaming under various acoustic and thermal conditions. The phenomenon under consideration has very rich physics, and some of the accompanying effects are discussed. Gravity may significantly reduce or augment streaming and heat transport, and a simple model has been derived to account for its effect. At the ends of a thermal buffer tube, the gas moves periodically between the nearly adiabatic environment of the tube and the nearly isothermal environment of the adjacent...