The Sherwood number is the dimensionless quantity that represents the ratio of which two types of mass transfer?

The Sherwood number is the dimensionless quantity that represents the ratio of which two types of mass transfer?

• A. Convective mass transfer to diffusive mass transfer
• B. Heat transfer to mass transfer
• C. Diffusive flux to convective flux
• D. Mass transfer coefficient to area

Answer: (A)

The Sherwood number measures how effective convection is compared to diffusion in moving a species through a boundary layer. It is defined as Sh = k_L L / D_AB, where k_L is the convective mass transfer coefficient, L a characteristic length, and D_AB the diffusivity of A in B. This ratio directly compares the convective flux to the diffusive flux across the same interface: a larger Sh means convection dominates, while a smaller Sh means diffusion plays a bigger role. It’s the mass-transfer analogue of the Nusselt number for heat transfer. So the dimensionless quantity represents the ratio of convective mass transfer to diffusive mass transfer.

The Sherwood number measures how effective convection is compared to diffusion in moving a species through a boundary layer. It is defined as Sh = k_L L / D_AB, where k_L is the convective mass transfer coefficient, L a characteristic length, and D_AB the diffusivity of A in B. This ratio directly compares the convective flux to the diffusive flux across the same interface: a larger Sh means convection dominates, while a smaller Sh means diffusion plays a bigger role. It’s the mass-transfer analogue of the Nusselt number for heat transfer. So the dimensionless quantity represents the ratio of convective mass transfer to diffusive mass transfer.