Stirling engines, especially free-piston Stirling engines (FPSE), have drawn more attention with the advantages of high thermal efficiency, constant power output, the flexibility to use any heat source as input and low noise. Acoustic impedance match is critical to the overall performances of a free-piston Stirling generator (FPSG). Based on thermos-acoustic theory, the acoustic impedance characteristics of the FPSE and the linear alternator are calculated and analyzed individually. And the acoustic impedance of the FPSE and the linear alternator are then well matched. In the calculation, the FPSG output the electric power of 6223.2 W with the thermal-to-electric efficiency of 38.3% at the heating temperature of 900 K. The acoustic match approach would be helpful for designing FPSGs.
Keywords Stirling, impedance, acoustic match, engine, linear alternator