Air at 1 atm flows at a Reynolds number of 50000 normal to a long circular 1 inch diameter cylinder made of naphthalene, for a temperature of 100c

vapor pressure of naphthalene = 10 torr;

viscosity of air = 0.0215 cP;

molar density of air = 0.0327 kmol/m3;

and diffusivity of naphthalene in air = 0.94 x 105 m2/s.

Calculate the initial average rate of sublimation in kmol/sm2 for a spherical particle of 1 in initial diameter and comapre this result to that for a bed packed with naphthalene spheres with a void fraction of 0.5