Naphthalene ball with 5 cm diameter is placed in a stagnant air at 40ºC and 1 atm. Molar evaporation flux of this ball is 1.47×10^-3 mol/m2 .s. The vapor pressure of naphthalene is 15.2 kPa at 40ºC and it has a negligible concentration in the bulk phase. Calculate the mass transfer coefficient (kc). (Assume that the system is dilute) µair = 1.8×10-5 kg/m.s; =1.123 kg/m3
; R=82.06 cm3.atm/mol.K at process conditions.
Sh= 2+0.6(Re)^0.5(Sc)^0.33