Numerical investigations on energy conversion performances in twin standing-wave thermoacoustic engines with various geometric and operational conditions

•The present model results agree better with experiments for twin TAEs than DeltaEC.•The optimal working gas and charge pressure for the twin TAE model is helium at 0.6 MPa.•The nonlinearities in the acoustic and flow fields of the twin TAE are well captured by our model.•The TAE model with a tapered conical resonator exhibits the highest acoustic power output.