New engines based on thermoacoustic effects

固体壁面与振荡气体之间的热相互作用产生了丰富多样的热声现象，如自持气体振荡和声热泵浦。热流和工作流之间的能量转换发生在一堆平板中，导致了两种类型的发动机。一个是原动机(热声发动机)，另一个是热泵。这些发动机分为驻波热声发动机和行波热声发动机两大类。实验研究了这种热声发动机的基本特性。通过测量气体的压力和速度，实验研究了带有差热叠层平板的谐振器中的气体自发振荡。观察到气团所做的功随着温度梯度流出堆栈。本文首次对驻波热声振荡器的工作流程和工作源进行了测量。将结果与基于热声理论的计算机模拟结果进行了比较，为驻波热声发动机的基本思想提供了有力的支持。我们建立了一个由环管中的差热叠板和观测到的行波模式绕环运行的自发气体振荡组成的热声发动机。将稳定性边界和热产生的声功率与在谐振器中测试的发动机的稳定性边界和热声功率进行了比较。环形管中的发动机相当于一个行波功率放大器，其起始温度比谐振器中的发动机要小得多。

Thermal interactions between solid walls and oscillating gas produce a rich variety of thermoacoustic phenomena such as self-sustained gas oscillations and acoustic heat pumping. The energy conversion between heat flow and work flow occurs in a stack of plates, resulting in the two classes of engines. One is the prime mover (thermoacoustic engine) and the other is the heat pump. These engines are divided into two groups called "standing wave thermoacoustic engine" and "traveling wave thermoacoustic engine". This work is to experimentally study basic properties of such thermoacoustic engines.A spontaneous gas oscillation in a resonator equipped with a differentially heated stack of plates is studied experimentally by measuring the pressure and velocity of the gas. Work done by gas parcels is observed to flow out of stack with a temperature gradient. This paper reports the first measurements of the work flow and the work source in the standing wave thermoacoustic oscillation. Results are compared with the computer simulation based on the thermoacoustic theory and provide strong support for the basic ideas of standing wave thermoacoustic engines.We have built a thermoacoustic engine consisting of a differentially heated stack of plates in a looped tube and observed spontaneous gas oscillations of the traveling wave mode running around the loop. Stability boundary and thermally produced acoustic power are compared with those for the engine tested in a resonator. The engine in a looped tube acts as a traveling wave power amplifier, whose onset temperature rations are significantly smaller than those for the engine in a resonator.