Large eddy simulations of differential molecular diffusion in non-reacting turbulent jets of H2/CO2 mixing with air
Large eddy simulations of differential molecular diffusion in non-reacting turbulent jets of H2/CO2 mixing with air
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DOI：
10.1063/1.4864097
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发表时间：
2014-02
影响因子：
4.6
通讯作者：
G. Maragkos;P. Rauwoens;D. Fauconnier;B. Merci
中科院分区：
文献类型：
--
作者：
G. Maragkos;P. Rauwoens;D. Fauconnier;B. Merci
Large eddy simulations of non-reacting H2/CO2 jets mixing with air are performed and the calculations are compared with the experiments reported by Smith et al. [“Laser Raman scattering measurements of differential molecular diffusion in non-reacting turbulent jets of H2/CO2 mixing with air,” Phys. Fluids 7, 1455–1466 (1995)]. The influence of differential diffusion effects for Reynolds numbers Re = 1000–8000 is analyzed and a differential diffusion parameter, ξ, is defined on the basis of normalized H2 and CO2 concentrations in order to quantify the effects of differential diffusion with increasing Reynolds number. The analysis is made not only in physical space but also with scatter plots and histograms. The simulation results reveal that differential diffusion effects are significant at downstream locations (more than 15 nozzle diameters away from the inlet) only for the lower Reynolds numbers (Re = 1000–2000). However, differential diffusion effects are present for all Reynolds numbers examined close to the inlet (closer than 10 nozzle diameters). This is not only confirmed by the mean results of the differential diffusion parameter, ξ, but also by looking at the histograms of ξ. This is an important indication that differential diffusion can be important in turbulent reacting flows if laminarization of the flow or weakening of turbulent diffusion occurs. Including differential diffusion effects in turbulent reactive flows involving mixtures with vastly different mass diffusivities can, therefore, improve the accuracy of numerical simulations. Results obtained assuming equal species mass diffusivities revealed that differential diffusion effects do not have any significant influence in the velocity field.Large eddy simulations of non-reacting H2/CO2 jets mixing with air are performed and the calculations are compared with the experiments reported by Smith et al. [“Laser Raman scattering measurements of differential molecular diffusion in non-reacting turbulent jets of H2/CO2 mixing with air,” Phys. Fluids 7, 1455–1466 (1995)]. The influence of differential diffusion effects for Reynolds numbers Re = 1000–8000 is analyzed and a differential diffusion parameter, ξ, is defined on the basis of normalized H2 and CO2 concentrations in order to quantify the effects of differential diffusion with increasing Reynolds number. The analysis is made not only in physical space but also with scatter plots and histograms. The simulation results reveal that differential diffusion effects are significant at downstream locations (more than 15 nozzle diameters away from the inlet) only for the lower Reynolds numbers (Re = 1000–2000). However, differential diffusion effects are present for all Reynolds numbers examined close ...
