Flow dynamics of shear-coaxial cryogenic nitrogen jets under supercritical conditions with and without acoustic excitations

The three-dimensional flow structures and dynamics of shear-coaxial nitrogen jets under supercritical conditions are comprehensively investigated using the large-eddy simulation technique. theoretical framework is based on full conservation laws accommodates real-fluid thermodynamics transport theories over entire range fluid states. Cryogenic liquid (132 K) delivered through inner tube a nozzle, gaseous (191 injected outer annulus, into high-pressure environment at 233 K. Particular attention paid to influence operating parameters evolution coaxial jets. Two pressure conditions, 4.94 10.0 MPa, three outer-to-inner velocity ratios in 2.03–3.75, considered. Results reveal that flowfield downstream characterized by two potential cores shear layers. counter-rotating recirculation zones formed next central post-tip. characteristic frequencies shear-layer instability analyzed power spectral analysis. Increasing ratio enhances turbulent mixing, promotes entrainment stream region, advances pinching point vortical motion centerline, thereby leading decreased length dark core. predicted core spreading angle show good agreement with experimental results. introduction transverse acoustic excitation induces large sinusoidal oscillations dense-fluid along direction mixing streams.