ZHANG Enbo, FENG Yanli, WU Yiming, et al. Turbulent Kinetic Energy Dissipation Mechanism of Supercritical Carbon Dioxide Leakage Flow in a Scallop Bionic Seal Cavity[J]. Journal of Xi'an Jiaotong University, 2026, 60(7): 13-23.
DOI:
ZHANG Enbo, FENG Yanli, WU Yiming, et al. Turbulent Kinetic Energy Dissipation Mechanism of Supercritical Carbon Dioxide Leakage Flow in a Scallop Bionic Seal Cavity[J]. Journal of Xi'an Jiaotong University, 2026, 60(7): 13-23.DOI: 10.7652/xjtuxb202607002.
Turbulent Kinetic Energy Dissipation Mechanism of Supercritical Carbon Dioxide Leakage Flow in a Scallop Bionic Seal Cavity
To accurately characterize the complex flow process of supercritical carbon dioxide(sCO
2
)leakage flow in a scallop bionic seal cavity and to elucidate the mechanism of turbulent kinetic energy(TKE)dissipation,a high-order numerical simulation method for real gas flows with strongly variable physical properties in rotating machinery was proposed.In this method,the uni-particle upwind scheme was employed for numerical flux splitting,while third-order numerical flux reconstruction was achieved via the simple high-resolution upwind method.Euler's fully implicit time-stepping iterative method was implemented,supporting open multi-processing(OpenMP)shared-memory parallel computing.A coupled iterative calculation method,integrating a real gas equation of state(EOS)with Helmholtz free energy-based thermophysical property lookup table,was adopted to
accurately capture the nonlinear variations in CO
2
thermophysical properties,with calculation deviations below 0.5%.The accuracy of this numerical simulation method was validated through molecular tracing experiments.Furthermore,the spatial distribution of leakage flow vortices within the scallop bionic seal cavity and its impact on the TKE dissipation rate were analyzed in detail.The results indicate that as the sCO
2
leakage flow enters the seal cavity,expansion occurs,while the local Mach number remains below 0.1.Under the rapid shear of the rotor,the leakage flow generates vortices that exhibit migration,splitting,and separation behaviors.The normalized helicity of the leakage flow exhibits alternating positive and negative values,indicating the presence of multiple sets of counter-rotating(clockwise and counterclockwise)vortices within the seal cavity.Each set of counter-rotating vortices increases the dimensionless TKE dissipation rate to over 1.95 × 10
8
,thereby effectively improving sealing performance.Moreover,the extrema of the TKE dissipation rate were identified at the outer boundaries of these counter-rotating vortices,where changes in vortex rotation direction also increase the TKE dissipation rate of the leakage flow.
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Related Institution
School of Energy and Power Engineering,Xi'an Jiaotong University
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