Gonen Eran, Grossman Gershon
Qnergy, Ein Harod Ihud 18960, Israel.
Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
J Acoust Soc Am. 2015 Sep;138(3):1537-48. doi: 10.1121/1.4928972.
Conventional reciprocating pistons, normally found in thermoacoustic engines, tend to introduce complex impedance characteristics, including acoustic, mechanical, and electrical portions. System behavior and performance usually rely on proper tuning processes and selection of an optimal point of operation, affected substantially by complementary hardware, typically adjusted for the specific application. The present study proposes an alternative perspective on the alternator behavior, by considering the relative motion between gas and piston during the engine mode of operation. Direct analytical derivation of the velocity distribution inside a tight seal gap and the associated impedance is employed to estimate the electro-acoustic conversion efficiency, thus indicating how to improve the system performance. The influence of acoustic phase, gap dimensions, and working conditions is examined, suggesting the need to develop tighter and longer seal gaps, having increased impedance, to allow optimization for use in upcoming sustainable power generation solutions and smart grids.
