| Thermoacoustic engine, which can convert heat energy to acoustic power, works by thermoacoustic effect. It can works for a long time because there are no moving parts in the engine. And it won't pollute the environment because of its harmless working gas. Therefore, many scientists and technicians spent much time on the research of the engine. Well, Thermoacoustically driven pulse tube cooler is a focus in this filed.Thermoacoustic history is reviewed, followed by brief introduction of theory of linear thermoacoustic and fluid network. Concerned with acoustic amplifier, which can amplify the pressure ratio of thermoacoustic engine, many researches were made, including introducing the linear theory of acoustic amplifier, creating the CFD models, simulating the acoustic amplifier with FLUENT, doing experiments on the influences on the pressure ratio, delivered acoustic power of thermoacoustic engine and thermoacousticlly driven pulse tube cooler with acoustic amplifier.This thesis is primarily concerned with acoustic amplifier. After calculating different acoustic amplifiers with different lengths, the calculated results reveal that the amplification ratio of acoustic amplifier, whose length is 1/4 wavelength, is the biggest, more than 6. And the calculated results also reveal that not only the amplification effect of the acoustic amplifier will decrease along with the decreasing of the impedance of the load, but also the acoustic power consumed by the amplifier is very large. Then, experiments certify this result. The acoustic amplifier, with length 2.8m and i.d. 8mm, can enhance the pressure ratio from 1.2? to 1.5. However, the acoustic power which is consumed by the acoustic amplifier is about 50% of the delivered acoustic power of engine. Finally, the cooling temperature of the thermoacousticlly driven pulse tube cooler is deceased from 83.5K to 81.6K with the acoustic amplifier.
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