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 2.54P
To determine
Rate of heat flow per meter length from inner to outer surface of the moulded insulation
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I want to know how much heat the tube lost due to the material it is made of aluminum or steel. Even if it is a small difference in temperature. I want to know which material Conduct Heat the Best through this problem.
material: Aluminum, steel ( the dimensions are the same for both)
temperature touching cylinder: 65 Celcius
temeprature inside cylinder 64.5 celsius
room temperature 24 celcius
Tube measurements
outer radius r1
r1 = 4 in
inner radius r2
r2 = 3 in
outer circumference C1
C1 = 25.132741228718 in
inner circumference C2
C2 = 18.849555921539 in
height
h = 8 in
wall thickness
t = 1 in
X Your answer is incorrect.
A dormitory at a large university, built 50 years ago, has exterior walls constructed of L, = 25-mm-thick sheathing with a thermal
conductivity of k, = 0.1 W/m-K. To reduce heat losses in the winter, the university decides to encapsulate the entire dormitory by
applying an L; = 25-mm-thick layer of extruded insulation characterized by k; = 0.029 W/m-K to the exterior of the original
sheathing. The extruded insulation is, in turn, covered with an Lg = 5-mm-thick architectural glass with kg = 1.4 W/m-K. Determine
the heat flux through the original and retrofitted walls when the interior and exterior air temperatures are T = 22°C and To =
O°C, respectively. The inner and outer convection heat transfer coefficients are h; = 5 W/m?-Kand h,
00,
25 W/m2-K, respectively.
The heat flux through the original walls is 1.46
W/m?.
The heat flux through the retrofitted walls is
0.92
W/m?.
3.6
Heat losses through windows in buildings are substantial. What would be the percentage reduction in heat loss that would be mitigated by replacing a window containing a single pane of glass with (a) double-pane low-E insulating glass or (b) a 3-inch-thick sheet of expanded polystyrene sheet? The quoted R values for these items are: • single pane of glass: 0.90 ft 2 hr ° F/Btu, • double pane of low-E insulating glass: 2.3 ft 2 hr ° F/Btu, • 1-inch-thick sheet of polystyrene sheet: 4.0 ft 2 hr ° F/Btu.
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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- Please solve the question on the sheet and get a clear picture and submit the picture. thankyouarrow_forwardThe interior-wall temperature of an annealing oven constructed of firebrick (Missouri) is2552°F, and the exterior-wall temperature is 392°F. If the heat loss is 3600 Btu/(hr)(sq ft),determine the thickness of the wall, in inches. (answer 5.67”)arrow_forwardIn the figure below, it is known that the thermal conductivity of k1 = 0.06 W/mK, k3 = 0.04 W/mK, and k4 = 0.12 W/mK. The thickness of the layers is L1 = 1.50 cm, L3 = 2.8 cm, and L4 = 3.50 cm. Known temperatures T1 = 30°C, T12 = 25°C, and T4 = -10°C. Energy transfer through walls is constant. How much is T34?arrow_forward
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- kindly help me with this one. Write your answer with four decimal places and enclose them in a box. Solve as neatly as possible. A sheet of Invar is 0.60in. thick and the temperatures at the two faces are 402degF and 222degF. Compute (a) the heat flux through the Invar sheet; (b) heat loss per hour if the are of the sheet is 6.4 square feet; (c) heat loss per hour if pyrex glass instead of Invar is used; and (d) heat lost if Invar is used and the thickness is increased by 0.80in.arrow_forwardThe temperatures of each node are shown in the figure and all values are given. Find the heat loss from the top surface of the plate to the environment. h=12 W/(mC) T₁₂ = 18°C 60.00°C 21.15°C 23.39°C 38.52°C Axy-0.05 m 60.00°C 95.11 178.70°C 364.13 c -0.02 W/m˚C) 60.00°C 120.60 C 232.6°C 450.55" q=122 W/m² Lütfen birini seçin: O a. 21.55 W O b. 22.32 W O c. 30.33 W O d. 38.40 W c. 23.88 Warrow_forwardi need the answer quicklyarrow_forward
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