Theoretical Study On Onset Of Standing-wave Thermoacoustic Engine

Thermoacoustic engine is a machine capable of converting thermal energy into acoustic energy. Such a thermoacoustic system appears so attractive because of its simplicity, high reliability, long lifetime and low cost that its onset theory is becoming a hot issue.The importance of the research on thermoacoustic is discussed at first. Then the developments of the thermoacoustic machine are reviewed. The thermoacoustic theory is introduced from different points of view. Two typical style of thermoacoustic engine are discussed, followed by thermodynamic circle, principal equations, fluid network principle and oscillation theory. The object researched in this paper is the gases in regenerator of standing-wave thermoacoustic engine, the whole onset process is divided into two parts, in the first part distribution of temperature in regenerator is obtained. By analysis and comparing to the experimental results, it is proved consistent with the experimental results. In the second part for the first time oscillation theory is used, by some primary work, self-excited oscillation and critical resistance in regenerator are put forward, on this basis, some primary quantitative computation and qualitative analysis are done.In this paper it is believed that the onset process is from the unorderly sound waves generated by heated gases, through ordering the sound waves, regenerator onset in a high natural frequency, followed by steady oscillation whose frequency is controlled by resonance tube. During this process heat energy first converts to unorderly sound waves, then to high frequency sound waves, finally ends up with low frequency sound waves.