Simultaneous heat and mass transfer takes place in a stagnant gas film $($of A and B$)$ at steadySimultaneous heat and mass transfer takes place in a stagnant gas film $($of A and $B)$ at steady

gtate, as shown in the figure below. Let A denote $CC{l}_4,$ and $B$ denote $O_2.$ The temperature

at the liquid A$-$gas interface is $0C$ while that at the top $($i$.$e$.$ the cold surface$)$ is $-50C.$

Calculate the following:

$($a$)$ The molar flux of evaporation of $CC{l}_4$

$($b$)$ The temperature at the midpoint between the cold surface and the liquid$-$gas interface

$($c$)$ The heat flux at the cold surface and at the hot surface $($i$.$e$.$ liquid A$-$gas interface$)$

$($d$)$ The quantity in $($c$)$ if you consider contribution only from conduction and the ratio

between the two.

What conclusions can you draw from the results obtained in $($b$),($c$)$ and $($d$)?$

Given:

i$.,D_{CC{1}_4-O_2}=0\mathrm{.}0636c\frac{m^2}{s}$

ii$.$ Total pressure is $1$atm

iii. Gas$-$film thickness, $=2cm$

iv$.,C_{p,C.L_4}=82\mathrm{.}65\frac{J}{m}$ole$*K$

v$.$ Effective thermal conductivity of the gas film may be assumed to be $2{10}^{-2}\frac{W}{m}*K$

vi$.$ The vapor pressures of $CCl$ at $0C$ and $-50C$ are $0\mathrm{.}043$atm and $0\mathrm{.}001$atm

respectively.

vii. Boling point of $CCl4$ is $76\mathrm{.}7C$ while that of $O_2$ is $-183C$

All thermophysical properties are evaluated at the film temperature. Assume equilibrium at

the interfaces. State any other assumptions you make.

state, as shown in the figure below. Let A denote $CC{l}_4,$ and $B$ denote $O_2.$ The temperature

at the liquid A$-$gas interface is $0C$ while that at the top $($i$.$e$.$ the cold surface$)$ is $-50C.$

Calculate the following:

$($a$)$ The molar flux of evaporation of $CC{l}_4$

$($b$)$ The temperature at the midpoint between the cold surface and the liquid$-$gas interface

$($c$)$ The heat flux at the cold surface and at the hot surface $($i$.$e$.$ liquid A $-$gas interface$)$

$($d$)$ The quantity in $($c$)$ if you consider contribution only from conduction and the ratio

between the two.

What conclusions can you draw from the results obtained in $($b$),($c$)$ and $($d$)?$