Study on the thermoacoustic system using moisturized stack-energy generation ratio of air and water vapor during system operation

In order to clarify the principle of oscillation in a two-phase fluid thermoacoustic engine, energy generation in a moisturized stack is theoretically investigated. Theoretical equations to express the energy generation are derived first using Raspet's theory. The validity of derived equations was suggested by comparing the calculated value and the measured value. Furthermore, on the basis of derived equations, the distribution of the energy generation in a moisturized stack and the ratio of the energy generations in air and water are derived with the measurement results for temperature distribution in the stack. As a result, it is confirmed that the energy generation based on the phase transition of water is significant near the hot end of the stack and occupies around 60% of the total energy generation in a two-phase fluid thermoacoustic engine. It is also suggested that the optimum length of stack may exist.