Numerical and experimental research on a high-power 4-stage looped travelling-wave thermoacoustic electric generator1

Abstract Looped travelling-wave thermoacoustic electric generator (LTTAEG) can transform thermal energy to electric power using thermoacoustic effect. Based on our previous effort on multi-stage LTTAEG with side-branched and dual-opposed linear alternators (LAs) as acoustic-to-electric transducers, for a higher output electric power and thermal-to-electric efficiency, a 4-stage LTTAEG is studied numerically and experimentally in this paper. In the simulation, the performance of 4-stage looped thermoacoustic heat engine is investigated based on linear thermoacoustic theory while the performance of dual-opposed LA is studied based on a novel network model. A new coupling algorithm between the 4-stage looped TAHE and dual-opposed LA is also proposed. In experiment, with 6 MPa pressurized helium as working gas, 650 oC and 25 oC heating and cooling temperatures. A highest electric power of 6.1 kW with thermal-to-electric efficiency of 15.86% and a highest thermal-to-electric efficiency of 19.64% with electric power of 4.37 kW is obtained when the electric capacitance connected to the LA is 17 μF and the electric resistance is 40 Ω and 75 Ω, respectively. Due to the high oscillating pressure in the system, some nonlinear phenomena have caused the simulation results deviated from the experimental results, especially in acoustic power and electric power, which should be investigated and considered in the future study.