
Fins and Heat Sinks 137
the n is
and from the base at x = L to the n is
and total heat transfer rate
from the exposed surface of the n is
Example 7.1
Consider an aluminum rectangular fin with base area of 2 mm × 40 mm and
length of 30 mm. Let’s assume that the combined convection and radiation heat
transfer coefficient is 30 W/m
2
°C, ambient temperature is 25°C, fin base tem-
perature is 90°C, and thermal conductivity of aluminum is 210 W/m°C. Compute
temperature distribution in this fin and heat transfer rate from it assuming (a) the fin
is infinitely long, (b) the fin tip is adiabatic, (c) combined convection ...