Simulação numérica da transferência de massa de compostos odorantes através da interface de um sistema multifásico líquido-gás
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Data
2015-12-04
Autores
Feroni, Rita de Cassia
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Universidade Federal do Espírito Santo
Resumo
The emission odorous compounds from liquid-gas interface can be represented from multiphasic flow and the generation of turbulence occurs close to the liquid-gas interface. Other characteristics are the likely configurations of the deformable interface with the presence or not of waves. The major part of the resistance to mass transport through liquid-gas interface is limited to a thin sub-layer from both sides of interface, in a few millimeters of dimension, where the turbulence is small and the diffusion processes become dominant, the relation between turbulence flow and the interface configuration (related to Reynolds number) together with the properties of the compound, as the diffusivity (related to Schmidt number) and solubility (related to Henry’s constant), are primordial to the study of mass transfer. In this work, in order to investigate the relation between the parameters quoted above, a multiphasic mass transfer assay was made using the computational model ANSYS-CFX 14.5, applying the turbulence model for large eddy simulation (LES). The mathematic model was validated with data of direct numeric simulations (DNS) from the work of Komori et al. (2010). The results show that the mass transfer is strongly affected by the presence of waves on interface, leading to the formation of turbulent structures in the liquid side. Thereby, values of mass transfer coefficients (kl) for different Reynolds numbers (210, 86 and 43) show large differences in order of magnitude. Likewise, considering odorous compounds with different values for Henry’s constants, this work show that the mass transfer also has a strongly dependence with this parameter. Higher values of kl are found for odorous compounds such as hydrogen sulfide in which the mass transfer is controlled by liquid phase, followed by ammonia in which the mass transfer is controlled by both liquid and gas phases and the isovaleric acid with mass transfer controlled by the gas phase.
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Mass transfer , Multiphase Flow , Odorant compounds , Turbulence , Henry's law , Lei de Henry , Transferência de Massa , Compostos Odorantes , Constante de Henry