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 2.48P
The handle of a ladle used for pouring molten lead is 30 cm long. Originally the handle was made of
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2. You are working at a company that uses cooked eggs in one of your processes. Imagine that you can treat an
egg as a 5.5 cm diameter sphere with properties similar to water (k= 0.6 W/m-°C, a = 1.4 x10" m²/s). The
eggs are initially at a uniform temperature of 8C and are dropped into boiling water that is at 97°C. Assume
the convection heat transfer coefficient in the boiling water to be h = 1400 W/m2.°C. If you are analyzing a
single egg in this process, how long will it take for the center of the egg to reach 70°C?
Example: 0.5 kg of water per minute is
heated from 20° to 40°C when passed
through a tube of 2.5 cm diameter steel pipe.
The pipe surface temperature is maintained at
110°C by condensing steam on its surface.
Find out the length of the pipe required. The
properties of water at mean temperature of
70°C are given below:
p = 978 kg/m²
k= 0.575 W/m. K
Cp = 4200 J/kg. K
v = 0.415 x 10-6 m²/sec
A 0.5-ampere current is flowing through a long electrically conducting cylindrical rod.
The diameter of the rod is 6 mm, the electrical resistance of the rod is R = 2000 /m,
and k =0.9 W/m K for the rod. The rod is encased in a 2-mm thick Pyrex tube and a
20°C liquid is flowing over the outer surface of the Pyrex tube. The convection heat
transfer coefficient for the liquid h= 800 W/m2 . K. The interfacial conductance (contact
resistance) at the interface between the rod and the Pyrex tube is h = 1200 W/m² - K.
a) Compute the rate of heat generation in the rod and use it compute the volumetric
rate of heat generation.
b) Find the temperature drop across the interface between the outer surface of the rod
and the inner surface of the Pyrex tube.
c) Find the temperature at the center of the rod.
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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