A turbine blade 6.3-cm-long, with cross-sectional area A = 4.6 x 10–4 m2 and perimeter P = 0.12 m, is made of stainless steel (k = 18 W/(m K). The temperature of the root, Ts, is 482°C. The blade is exposed to a hot gas at 871°C, and the heat transfer coefficient h? is 454 W/(m2 K). Determine the temperature of the blade tip and the rate of heat flow at the root of the blade. Assume that the tip is insulated.
GIVEN
FIND
ASSUMPTIONS
Steady state conditions prevail
The thermal conductivity is uniform
The tip is insulated
The cross-section of the blade is uniform
One dimensional conduction
SKETCH
(a) The temperature distribution in a fin of uniform cross-section with an insulated tip,
At the blade tip, x = L, therefore
(b) The rate of heat transfer from the fin is given
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The circuit below contains three 100-watt light bulbs and a capacitor. The emf ? = 110V. The capacitor is fully charged. Which light bulb(s) is(are) dimmest?
a.
A
b.
B
c.
C
d.
A and B
e.
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