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 2.29P
In a cylindrical fuel rod of a nuclear reactor, heat is generated internally according to the equation
where
Calculate the temperature drop from the centerline to the surface for a 2.5-cm-diameter rod having a thermal conductivity of
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An open system is often referred to as control volume, which is a properly selected
region in space in which mass and energy can flow across the boundaries as figure
1.2. The boundary of a open thermodynamic system is called the control surface
Across the Boundaries
E = Yes
F 0 = Yes
w =Yes
Control surface
ass YES
W
CONTROL
VOLUME
energy YES
Figure 1.2.
A cooling/heating radiator is an example of such a system – give two more examples of such
a system.
1.)An aluminum tank with a volume of 1000 liters is filled with gasoline. Both are at a temperature of 12°C. The tank is transported to a place where the temperature is 37° and, due to the difference between the volumetric expansion coefficients of the metal and the liquid, the ebb of the tank. Assuming the tank expands like a massive volume of aluminum, how many liters of gasoline overflow from the tank?
Data:
βaluminum=7*10-5/ºC and βgas=9.5*10-4/ºC
The left side of this equation tells how much energy Q the cylinder gives to the water while it cools. The right
side of this equation tells how much energy Q the water and aluminum cup absorb from the cylinder to warm
up. Because it is the same energy, they are equal.
What is known in this equation?
Mcyl
411.7 g, malum
46.5 g, malum+water
= 175 g
Can you find: mwater =? g
Twater = Talum = 20°C (water and cup of room temperature)
90°C, T; = 35°C (hot cylinder and cool "cylinder+cup+water" temperatures)
Tcyl
kCal
Calum = 0.22, Cwater
1 (specific heat of water and aluminum, measured in units
kg-°C
What are we looking for is Ccul - How we find it? Plug all the numbers into the equation (1), Ccul will be one
unknown which you can calculate from the equation. Important, convert all the masses from grams to kilograms!
After
you find Ccyl, compare it to known value for the copper 0.093(our cylinder is made out of copper).
|Ceyl -0.093|
% :
· 100%
0.093
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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