Theoretical and experimental study of a novel thermoacoustic engine for sound source application

This paper introduces a novel structures of standing-wave thermoacoustic engines designed for outdoor sound sources. The system is characterized by operational stability, enhanced SPL, and space-saving design. Compared to the conventional open-end system, the thin-plate sound source proposed is a closed-end one. The plate isolates the working gas from the external environment but remains acoustically transparent, enabling the use of alternative gases. Besides, it can effectively adjust the acoustic field distribution, enhance the acoustic power output. Experimental and theoretical research were conducted, the performance of systems using air or helium is analyzed and compared. The influence of thin plate properties on system behavior is investigated. Results show that with air as working gas, the system can achieve a higher SPL of 113.02 dB at 1 m away, marking a 5.4% increase in SPL compared to open-ended system. With helium adopted as the operational gas, the system can reach a highest SPL(1 m) of 123.49 dB with the condition of 0.3 mm SP and T_h = 675 K, indicating a 9.3% increase in SPL compared to system with air as working gas. The performance is significantly influenced by the thickness and Young's modulus. This system has potential for application as an outdoor sound source.