Page 20 - Packed bed columns for absorption, desorption, rectification and direct heat transfer
P. 20
15
For me same time interval dr trough the opposite walls of the
parallelepiped, the following quantities of heat go out:
-X—dydzdt + - A—f — \dxJy.dzdt (30)
dx \_ 8x\8xJ
. d(&}, , , ,
-A—dydzdt -1 — — \dx.dy.az.dT (31)
dy
l—dydzdT (32)
did)
dzidz)
The difference between the quantity of heat passing in and leaving the
parallelepiped through its opposite walls is:
on x axis
=Q X- ! (33)
'dx
on y axis
8h_
dQ v=Q v-Q v+a (34)
'ay
on z axis
2
8 t
dQ.=Q,-Q^,=- (35)
The total increase of the heat in the parallelepiped for time dr is
(36)
or
