An acoustical pump capable of significantly increasing pressure ratio of thermoacoustic heat engines

Pressure ratio is one of the important parameters for evaluating a thermoacoustic heat en- gine. A so-called acoustical pump, which is capable of significantly increasing pressure ratio of a ther- moacoustic heat engine, is proposed. Its operating principle is given. Also, a verification experiment is done with nitrogen gas in the energy-focused ther- moacoustic heat engine, showing that the pressure ratio increased from 1.25 to 1.47.