Abstract
We masured a thermal efficiency of a multistage thmoacoustic engine by a forced oscillation method. In the forced oscillation method, we can arbitrarily change the operating frequcncy and the acoustic power, independently of the temperature difference. As a result of the experiment we found that the themal efficiency of the thermoacoustic engine unit reached 6.58% which is 21.4% of Carnot effaaiciency when the operating frequency was 35 Hz and a hot end temperature was 150 ℃.
