Question

Which number is analogous to Prandlt number in terms of mass transfer?

(a) Sherwood number

(b) Schmidt number

(c) Reynolds number

(d) Nusselt number

The question was posed to me during an interview.

Enquiry is from Liquid- Solid Mass Transfer Correlations in portion Heterogenous Reactions of Bioprocess Engineering

Answer 1

The correct choice is (b) Schmidt number

For explanation: Schmidt Number, Sc, is a dimensionless parameter representing the ratio of diffusion of momentum to the diffusion of mass in a fluid. It is defined as

Sc = v/δ

where ν is kinematic viscosity and &delta diffusivity.

Schmidt number is the mass transfer equivalent of Prandtl Number. For gases, Sc and Pr have similar values (≈0.7) and this is used as the basis for simple heat and mass transfer analogies.