Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
8th Edition
ISBN: 9781305387102
Author: Kreith, Frank; Manglik, Raj M.
Publisher: Cengage Learning
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Chapter 2, Problem 2.44P
To determine the thermal conductivity of a long, solid 2.5-cm-diameter rod, one half of the rod was inserted into a furnace while the other half was projecting into air at
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To determine the thermal conductivity of
a long, solid 2.5-cm-diameter rod, one
half of the rod was inserted into a furnace
while the other half was projecting into
air at 27°C. After steady state had been
reached, the temperatures at two points
7.6 cm apart were measured and found to
be 126°C and 91°C, respectively. The heat
transfer coefficient over the surface of
the rod exposed to the air was estimated
to be 22.7 W/m²K. What is thermal
conductivity of the rod?
A long 20 cm diameter shaft made of stainless steel 304 comes out of an oven at a
uniform temperature of 600°C. The shaft is then allowed to cool slowly in an environment
at 200°C with an average heat transfer coefficient of h = 80 W/m².K. Determine [a] the
temperature at the center of the shaft and [b] the temperature of the outer surface of the
shaft 45 minutes after the start of the cooling
Given:
Find:
Schematic:
Assume:
Property Data:
k= 14.9 W/m°C
p= 7900 kg/m³
Cp = 477 J/kg:K
a= 3.95 x 10-6 m²/s
Two large steel plates at temperature of 90°C and
70°C are separated by a steel rod 2.5 cm diameter
and 0.25 m long. The rod is welded to each plate.
The space between the plates is filled with insulation
which also insulates the circumference of the rod.
Because of voltage difference between the two plates
current flows through the rod and the electrical
energy is dissipated at a rate of 10 W. Determine
the maximum temperature in the rod and the heat
flux at each end. Proceed to compare the net heat
flow rate of the two ends with the total rate of
heat generation.
Thermal conductivity for the rod material is
42.5 W/m-deg.
Chapter 2 Solutions
Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
Ch. 2 - A plane wall, 7.5 cm thick, generates heat...Ch. 2 -
2.2 A small dam, which is idealized by a large...Ch. 2 - 2.3 The shield of a nuclear reactor is idealized...Ch. 2 - A plane wall 15 cm thick has a thermal...Ch. 2 - 2.5 Derive an expression for the temperature...Ch. 2 - A plane wall of thickness 2L has internal heat...Ch. 2 - 2.7 A very thin silicon chip is bonded to a 6-mm...Ch. 2 - 2.9 In a large chemical factory, hot gases at 2273...Ch. 2 - 2.14 Calculate the rate of heat loss per foot and...Ch. 2 - 2.15 Suppose that a pipe carrying a hot fluid with...
Ch. 2 - Prob. 2.16PCh. 2 - Estimate the rate of heat loss per unit length...Ch. 2 - The rate of heat flow per unit length q/L through...Ch. 2 - A 2.5-cm-OD, 2-cm-ID copper pipe carries liquid...Ch. 2 - A cylindrical liquid oxygen (LOX) tank has a...Ch. 2 - Show that the rate of heat conduction per unit...Ch. 2 - Derive an expression for the temperature...Ch. 2 - Heat is generated uniformly in the fuel rod of a...Ch. 2 - 2.29 In a cylindrical fuel rod of a nuclear...Ch. 2 - 2.30 An electrical heater capable of generating...Ch. 2 - A hollow sphere with inner and outer radii of R1...Ch. 2 - 2.34 Show that the temperature distribution in a...Ch. 2 -
2.38 The addition of aluminum fins has been...Ch. 2 - The tip of a soldering iron consists of a 0.6-cm-...Ch. 2 - One end of a 0.3-m-long steel rod is connected to...Ch. 2 - Both ends of a 0.6-cm copper U-shaped rod are...Ch. 2 - 2.42 A circumferential fin of rectangular cross...Ch. 2 - 2.43 A turbine blade 6.3 cm long, with...Ch. 2 - 2.44 To determine the thermal conductivity of a...Ch. 2 - 2.45 Heat is transferred from water to air through...Ch. 2 - 2.46 The wall of a liquid-to-gas heat exchanger...Ch. 2 - Prob. 2.47PCh. 2 - The handle of a ladle used for pouring molten lead...Ch. 2 - 2.50 Compare the rate of heat flow from the bottom...Ch. 2 - 2.51 Determine by means of a flux plot the...Ch. 2 - Prob. 2.52PCh. 2 - Determine the rate of heat transfer per meter...Ch. 2 - Prob. 2.54PCh. 2 - 2.55 A long, 1-cm-diameter electric copper cable...Ch. 2 - Prob. 2.56PCh. 2 - Prob. 2.57PCh. 2 - Prob. 2.58P
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