Mode transition in a standing-wave thermoacoustic engine: A numerical study

This study investigates the mode transition phenomenon in a standing-wave thermoacoustic engine (TAE) by means of computational fluid dynamics (CFD). Firstly, steady-state responses TAE at selected temperature ratios are examined via continuous wavelet transform. The bifurcation diagram and spectral map indicate that, as ratio increases, experiences series bifurcations, through which first-mode periodic oscillations, quasiperiodic oscillations second-mode occur. Secondly, performances initial decay/build-up, nonlinear saturation steady states studied. onset first and/or second acoustic is identified dynamic decomposition. oscillation frequencies growth/attenuation rates from CFD agree well with those reduced-order network model. Nonlinear competition takes place during growth one affected or even totally inhibited other. At state, exhibit closed loop phase space whilst generate torus. time-averaged energy density, intensity efficiency increase increasing ratio. Finally, parametric studies conducted to investigate effects gap between stack plates position on transition. It found that will if near end small. Results this could become novel approach match external loads for higher electric power outputs.