For heat transfer to fluids flowing in the annular section between concentric tubes, following correlation for the

heat$-$transfer coefficient when considering the film on the inner tube:

$1$

$/=0\mathrm{.}031(1$

$)$

$0\mathrm{.}8()$

$0\mathrm{.}31(/$

$)$

$0\mathrm{.}14(2$

$/$d$1$

$)$

$0\mathrm{.}15$

where $1$and $2$ are the outer diameter of the inner tube and the inner diameter of the outer tube, respectively, is

the viscosity of the fluid at the bulk temperature of the fluid, and is the viscosity of the fluid at the heating surface

temperature. Use this equation and the analogy between heat and mass transfer to get the corresponding mass

transfer correlation that can be used to predict the mass$-$transfer coefficient from a naphthalene rod used to form the

inner tube of an annular duct