Investigation on acoustic radiation characteristics of an open-air traveling-wave thermoacoustic generator

The acoustic radiation impedance of an Open-air Traveling-wave ThermoAcoustic Generator (OTTAG) composed of a looped tube and a resonator was theoretically described. The acoustic radiation characteristics versus different resonator types and input heating powers of this OTTAG are experimentally investigated. The comparisons of sound pressure level (SPL) at 1m far away from the open end of the resonator were carried out in an anechoic chamber, a semi-anechoic chamber and a normal laboratory under different heating power. The results showed that the difference in a normal laboratory between the anechoic chamber and semi-anechoic chamber was lower than 1.5%. The maximum SPL at 1m far away from the open end of the resonator was up to 100.1 dB ref 20μPa. This OTTAG would be used as a newly basic acoustic source for low frequency and long-range noise experiments and industrial sources and vibration.