Investigation On A Travelling-Wave Thermoacoustic Engine

Thermoacoustic engine is a novel device that can convert heat to acoustic energy. It has advantages such as the simplicity, no moving parts, high reliability, long lifetime and no pollution. It can use energy of low quality such as solar energy, waste vapor energy, etc. In comparison with standing-wave thermoacoustic engine, travelling-wave engine has lower onset temperature, much higher pressure ratio and higher efficiency.The history of the thermoacoustic theory and thermoacoustic engines was reviewed in brief. The onset mechanism was analyzed and explained in details. Fluid network theory and its application to thermoacoustic engines were presented.A travelling-wave thermoacoustic engine was designed and constructed in Zhejiang University. A computer-aided acquisition system was successfully developed by using graphic programming language LabVIEW. The accuracy and reliability of the acquired data was considerably improved.The onset temperature of the system was comparably low. Even under the condition that the filling pressure was up to 1.5MPa, the onset temperature was only 237癈. With the filling nitrogen of 0.9 MPa, the maximal pressure ratio reaches 1.21 and the operation frequency is 25 Hz. The ratio of the harmonic wave of the engine was very little and the frequency jumping was not found in present experiments. Streaming from the hot end to the cold end of the regenerator was found which would waste much useful heating energy. Modified structure of the jet pump could control this sort of Streaming efficiently.