When an air freshener is hung up in the air and attached to the interior rear view mirror. The air stream picks up small concentrations of the air freshener and transport the fresh scent throughout the car. This is an example of mass transport through convection. So both heat and mass can be transported through the process of convection. Another way of mass transport is through diffusion. For the industry it is sometimes interesting to make mass transport very efficient. What will be the preferred process in that case? Convection or diffusion?

Convection in mass transfer can be explained by the dimensionless Sherwood number, which is dependent on the sort of flow.

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