
312 Heat Transfer: Thermal Management of Electronics
where
, T
s
, and T
∞
are the average heat transfer coefcient, the surface temperature
and the inlet uid temperature, respectively. Bar-Cohen and Rohsenow [9] gave the
following expression for the Nusselt number in this ow:
Nu
(Ra)
.
(Ra)
/
S
fS S
hS
k
C
SL SL
== +
−
1
212
287
//
112/
.
(12.64)
Here C
1
= 576 if both plates are at the same uniform temperature and C
1
= 144 if one
plate is at a uniform temperature and the other plate is adiabatic.
Now, let’s consider two vertical plates with the uniform surface heat ux
. The
convection heat transfer coefcient and the temperature at the end of each