Question

If D is the fluid dispersion coefficient, L is the length of spread of tracer and u is the fluid velocity, then  which of the following represents Dispersion number?

(a) \(\frac{L}{uD}\)

(b) \(\frac{L}{D}\)

(c) \(\frac{D}{uL}\)

(d) \(\frac{Lu}{D}\)

I got this question by my college director while I was bunking the class.

I'd like to ask this question from Non Ideal Reactors topic in chapter Compartment Models, Models for Non Ideal Reactors of Chemical Reaction Engineering

Answer 1

Right option is (c) \(\frac{D}{uL}\)

Easiest explanation: Dispersion number is a dimensionless group characterizing spread in the entire reactor vessel. The value of D determines the spread.