Modeling, construction, and testing of a diaphragm thermoacoustic Stirling engine

Highlights: • A diaphragm thermoacoustic Stirling engine is designed and developed. • A mechanical lumped model is presented for the diaphragm thermoacoustic Stirling engine. • The performance of the engine is studied using the mechanical lumped model. In this article, a diaphragm thermoacoustic Stirling engine is modeled, constructed, and tested. First, the working principle of the thermoacoustic system is justified based on a new nonlinear lumped mechanical model. Then, the existence of a stable limit cycle in the nonlinear dynamic response of the engine is predicted using the proposed mathematical framework. Additionally, the performance of the designed engine in terms of operating frequency, generated work, output power, pressure variations, and pressure difference caused by the core section is investigated. Next, in order to verify the presented mathematical model, an experimental thermoacoustic Stirling engine is developed and tested. It is found that the practical results are in a good agreement with the simulation outcomes through which the validity of the proposed model is affirmed. Finally, the inexpensive diaphragm thermoacoustic engine can operate at frequency of 13.8 Hz.