7/25/2019 mass transfer tutorial
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TUTORIAL 1
Q1: There is a 2 mm thick layer of water on the oor of the room.
The watervaporizes and diuses through a stagnant lm of air of
estimated thickness of 2.5mm on the water surface. nder the
condition of evaporation! the watertemperature is essentially e"ual
to its wet #ul# temperature. $f the am#ient
temperature is 2% degree &elsius! calculate the time
re"uired for the water layer todisappear completely for the
following cases:
a' The am#ient air has a relative humidity of ()*+#' The oor has
micro pores and the water penetrates the oor at a constant
rate of )., kg-m2.h! the am#ient air has humidity as in a'
iusivity of water vapor in air is ).%5/ ft2-h at , atm and
)0&+ 1ntoine e"uation isln pv,/.%53/45,().2-T! where pvis in
#ar+ at 2%0& and ()* relative humidity! thewet #ul# temperature
is 22.50&.
Q2:Two large vessels are connected #y a tu#e 5 cm in diameter
and ,5 cm in
length. essel , contains %)* 6271' and 2)* 82 79'+ vessel 2
contains 2)* 62and%)* 82. The temperature is 2)0& and the total
pressure is 2 atm. &alculate
a' The steady state u of 62and 82#' The partial pressure of
62and its gradient in the tu#e ).)5 m from vessel ,c' 6et mass u
with respect to stationary o#server
1ssume e"uimolar counter diusion
Q3:1 miture of ()* ;2 and
