Observation of local energy conversion and entropy production in a thermoacoustic heat engine

通过同时测量具有轴向温度梯度的充气管中的压力、速度和温度振荡，对热声能量转换进行了实验研究。压力和速度之间的相位差被发现是一个关键的参数，控制热力学过程的相位构成一个热力学循环。此外，轴向工作流（声功率）被发现增加成比例的本地能量转换率的气体执行。这一结果支持热声现象的热力学方法。

Thermoacoustic energy conversion was experimentally studied through simultaneous measurements of pressure, velocity, and temperature oscillations in a gas-filled tube with axial temperature gradient. The phase difference between pressure and velocity was found out to be a key parameter governing the phasing of thermodynamic processes constituting a thermodynamic cycle. Also, the axial work flow (acoustic power) was found to increase in proportional to the local energy conversion rate that the gas executed. This results supports the thermodynamic approach to thermoacoustic phenomena.