Investigating the onset and steady-state conditions of a diaphragm thermoacoustic stirling engine

This work investigates the onset and steady-state conditions of diaphragm thermoacoustic Stirling engines using the averaging-based Lyapunov technique for the first time. First, the diaphragm thermoacoustic Stirling engine is introduced. Next, the startup conditions, including the onset condition and existence of a stable limit cycle (steady-state) of the engine are studied based on the alteration of the mass connected to the diaphragm of SUTech-SR-3 in the range of 88.2 g to 121.2 g. The simulation results obtained from the averaging-based Lyapunov technique show the engine can run only in the mass range of 90.4 g to 119 g. On the other hand, to validate the simulation outcomes, this assessment is carried out experimentally. The practical results confirm the extracted outcomes from this method. Based on the allowable range acquired from this technique, the effect of the change in the value of the mass connected to the engine diaphragm on the operating frequency is investigated experimentally. This work shows that the employed method can be a helpful means to investigate the startup conditions of the diaphragm thermoacoustic Stirling engines.