EDDY NUMBER DISTRIBUTION IN ISOTROPIC TURBULENCE AND ITS APPLICATION FOR ESTIMATING MASS TRANSFER COEFFICIENTS

摘要

The eddy number distribution for isotropic turbulent flows has been derived by manipulating well-established formulae for describing turbulence. The distribution has been used to derive an expression relating the fractional rate of surface renewal, and hence mass transfer coefficients across gas-liquid interfaces, to key process variables such as the local energy dissipation rate and the Kolmogorov scale. The expression has been compared with the previously published roll-cell and eddy-cell models, which were applied to correlating local mass transfer coefficients in a pipe and an open absorption channel. Excellent agreement has been found. The expression has also been applied to correlating the gas-side mass transfer coefficients for liquid evaporation in wetted wall pipe flows, and the mass transfer coefficient for solid dissolution adjacent to a solid-liquid interface in a stirred tank. The theoretical correlations have been validated by published experimental data.