Forced convection natural, combined with

Experimental gas-solid mass-transfer data have been obtained for naphthalene in CO9 to develop correlations for mass-transfer coefficients [Lim et al., Am. Chem. Soc. Symp. Ser, 406, 379 (1989)]. The data were correlated over a wide range of conditions with the following equation for combined natural and forced convection ... 

Effect of Evaporation Condition Previous studies on more traditional applications have investigated the effect of increased air velocity, that is, forced-convection conditions for a combination of dry/wet phase inversion techniques to produce defect-free, ultrahigh flux asymmetric membranes with ultrathin skin layers [115-117]. To investigate the effect of evaporation condition on the release rate of drug, tablets were dip coated with CA solution containing 10% CA, 80% acetone, and 10% water and allowed to dry by blowing air across the surface with a blower (forced convection). As a comparison, tablets coated with the same solution were air dried under natural free-convection conditions. 

In Equations (26.78a,b), the subscripts F and N refer to forced and natural convection stirring. In Equations (26.79a-d), L is a characteristic electtode dimension, D is the diffusion coefficient, v is velocity, g is the gravity acceleration constant, p is viscosity, is bulk solution density, and Ap is the difference in density between the bulk solution and the solution at the electrode surface. Once a Sh or expression has been found/generated, it is combined with Equation (26.70) (or the analogous equation for a supporting electrolyte system) to obtain an / relationship. Examples of mass transfer correlations follow. 

A. P. Hatton, D. D. James, and H. W. Swire, Combined Forced and Natural Convection With Low-Speed Air Flow Over Horizontal Cylinders, J. Fluid Mech. (42) 17-31,1970. 

Z. F. Dong, and M. A. Ebadian, Analysis of Combined Natural and Forced Convection in Vertical Semicircular Ducts with Radial Internal Fins, Numer. Heat Transfer, part A, (27) 359-372,1995. 

OSTRACH, S. 1980. Natural convection with combined driving forces. PhysicoChem. Hydrodynamics 1, 233—247. 

In the case of the direct alcohol fuel cells (DAFCs), e.g., direct methanol fuel cell (DMFC), the anode of a liquid-feed DMFC is supplied with a diluted methanol aqueous solution, while the cathode is fed with air or pure oxygen, which can be either forced by an external blower or driven by natural convection [19, 20], Due to the combined effect of both convection and diffusion, the methanol and the oxygen reach the anode and cathode CLs, respectively, where they undergo the overall electrochemical reactions ... 

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