Fire-driven flow analysis in the underground subway station has been performed with various main tunnel ventilations. Shin-gum-ho station （depth： 46 m） in Seoul is selected as a simulation model. The ventilation mo...Fire-driven flow analysis in the underground subway station has been performed with various main tunnel ventilations. Shin-gum-ho station （depth： 46 m） in Seoul is selected as a simulation model. The ventilation mode is assumed to be emergency state. Various main tunnel ventilations are applied to operate in a proper way for helping of smoke exhaustion in platform. The entire station is covered for simulation. Ventilation diffusers are modeled as 95 square shapes of 0.6 m × 0.6 m in the lobby and as 222 square shapes of 0.6 m × 0.6 m and four rectangular shapes of 1.2 m × 0.8 m in the platform. The total of 7.5 million grids is generated and whole domain is divided to 22 blocks for MPI （massage passing interface） efficiency of calculation. LES （large eddy simulation） is applied to solve the momentum equation. Smagorinsky model （Cs = 0.2） is used as SGS （subgrid scale） model. The distribution of CO （carbon monoxide） is calculated for various capacity of main tunnel ventilation and compared with each other.展开更多
Large-eddy simulation developments and validations are presented for an improved simulation of turbulent internal flows. Numerical methods are proposed according to two competing criteria： numerical qualities （preci...Large-eddy simulation developments and validations are presented for an improved simulation of turbulent internal flows. Numerical methods are proposed according to two competing criteria： numerical qualities （precision and spectral characteristics）, and adaptability to complex configurations. First, methods are tested on academic test-cases, in order to abridge with fundamental studies. Consistent results are obtained using adaptable finite volume method, with higher order advection fluxes, implicit grid filtering and ＂low-cost＂ shear-improved Smagorinsky model. This analysis particularly focuses on mean flow, fluctuations, two-point correlations and spectra. Moreover, it is shown that exponential averaging is a promising tool for LES implementation in complex geometry with deterministic unsteadiness. Finally, adaptability of the method is demonstrated by application to a configuration representative of blade-tip clearance flow in a turbomachine.展开更多
文摘Fire-driven flow analysis in the underground subway station has been performed with various main tunnel ventilations. Shin-gum-ho station （depth： 46 m） in Seoul is selected as a simulation model. The ventilation mode is assumed to be emergency state. Various main tunnel ventilations are applied to operate in a proper way for helping of smoke exhaustion in platform. The entire station is covered for simulation. Ventilation diffusers are modeled as 95 square shapes of 0.6 m × 0.6 m in the lobby and as 222 square shapes of 0.6 m × 0.6 m and four rectangular shapes of 1.2 m × 0.8 m in the platform. The total of 7.5 million grids is generated and whole domain is divided to 22 blocks for MPI （massage passing interface） efficiency of calculation. LES （large eddy simulation） is applied to solve the momentum equation. Smagorinsky model （Cs = 0.2） is used as SGS （subgrid scale） model. The distribution of CO （carbon monoxide） is calculated for various capacity of main tunnel ventilation and compared with each other.
文摘Large-eddy simulation developments and validations are presented for an improved simulation of turbulent internal flows. Numerical methods are proposed according to two competing criteria： numerical qualities （precision and spectral characteristics）, and adaptability to complex configurations. First, methods are tested on academic test-cases, in order to abridge with fundamental studies. Consistent results are obtained using adaptable finite volume method, with higher order advection fluxes, implicit grid filtering and ＂low-cost＂ shear-improved Smagorinsky model. This analysis particularly focuses on mean flow, fluctuations, two-point correlations and spectra. Moreover, it is shown that exponential averaging is a promising tool for LES implementation in complex geometry with deterministic unsteadiness. Finally, adaptability of the method is demonstrated by application to a configuration representative of blade-tip clearance flow in a turbomachine.
