Calculate the mass transfer coefficient $k_G$ in units of kgmo$\frac{l}{s*m^2*Pa}$ for water vapor in air at

$338\mathrm{.}6K$ and $101\mathrm{.}32$kPa flowing in a large duct past solids of different geometries. The velocity

of air in the duct is $3\mathrm{.}66\frac{m}{s}.$ The water vapor concentration in the air is small, so that the

physical properties of air may be used. Water vapor is being transferred to the solids in the duct.

Calculate $k_G$ for the following geometries.

a$.$ A single $2\mathrm{.}54cm$ diameter sphere.

b$.$ A packed bed of $2\mathrm{.}54cm$ diameter spheres with $=0\mathrm{.}35$

Hint: Don't forget to correct $D_{AB}$ for temperature using the ratio formula from the Fuller Method.

Table A$\mathrm{.}3-3$a can be used for physical properties. Example $21\mathrm{.}3-3$ will be useful here for part a$.$

In parts a and $b,$ you may select the proper mass transfer coefficient equation from the table at

the end of Chapter $21.$ The definition of the $J_D$ factor in equation $21\mathrm{.}3-5$ will also be needed in

part b$.$