Introduction to Heat Transfer
6th Edition
ISBN: 9780470501962
Author: Frank P. Incropera, David P. DeWitt, Theodore L. Bergman, Adrienne S. Lavine
Publisher: Wiley, John & Sons, Incorporated
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Chapter 2, Problem 2.36P
To determine
The heat diffusion equation for spherical coordinates.
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b) Using the heat diffusion equation which you have derived in part (a).
Let consider a one-dimensional plane wall that separate of two fluids which
is illustrated in Figure lb with constant properties (e.g. thermal
conductivity, k) and uniform internal generation (e.g. no heat generation)
and steady state condition (e.g no change in the amount of energy storage)
i) Find the expression of temperature distribution, T(x)
ii) and the expression of heat flow, q
Ts.
Cold fluid
T2 h2
Hot fluid
T2
T1. h
Lox
x = L
Figure 1b
Nuclear fuel rods. A typical nuclear fuel rod contains circular uranium oxide (UO2)
fuel pellets 10 mm in diameter and 5-mm thick stacked in a column to a length of
4 m inside a thin zirconium alloy tube, as shown below. The pellets generate heat
uniformly throughout their volume due to nuclear fission, with a power density a
(i.e., the heat power produced per unit volume of the pellet) that depends on their
235U enrichment. This heats up the water in the reactor to produce steam to drive
the turbine. Assuming that the rim of the fuel pellet is maintained at a constant
temperature Trim due to water cooling, show that the steady-state temperature
profile T(r), where r is the radial distance from the centre of the pellet and fuel rod,
4.
P(R? -r²;
is given by: T(r) = Tim +
4k
where k is the thermal conductivity of the
pellet and R is its radius.
partial stacked column
of fuel pellets in rod
An electrical resistance wire made of tungsten dissipates heat to the surroundings at a constant rate.
Which of the following equations are you going to use to compute for the temperature at any point
within the wire when the temperature throughout the whole wire no longer changes with time? Assume
that the wire can be approximated as a thin cylinder.
a. Fourier-Biot equation
b. Poisson equation
c. Diffusion equation
d. Laplace equation
Chapter 2 Solutions
Introduction to Heat Transfer
Ch. 2 - Assume steady-state, one-dimensional heat...Ch. 2 - Assume steady-state, one-dimensional conduction in...Ch. 2 - A hot water pipe with outside radius r1 has a...Ch. 2 - A spherical shell with inner radius r1 and outer...Ch. 2 - Assume steady-state, one-dimensional heat...Ch. 2 - A composite rod consists of two different...Ch. 2 - A solid, truncated cone serves as a support for a...Ch. 2 - To determine the effect of the temperature...Ch. 2 - Prob. 2.9PCh. 2 - A one-dimensional plane wall of thickness 2L=100mm...
Ch. 2 - Consider steady-state conditions for...Ch. 2 - Consider a plane wall 100 mm thick and of thermal...Ch. 2 - Prob. 2.13PCh. 2 - In the two-dimensional body illustrated, the...Ch. 2 - Consider the geometry of Problem 2.14 for the case...Ch. 2 - Steady-state, one-dimensional conduction occurs in...Ch. 2 - Prob. 2.17PCh. 2 - Prob. 2.18PCh. 2 - Consider a 300mm300mm window in an aircraft. For a...Ch. 2 - Prob. 2.20PCh. 2 - Use IHT to perform the following tasks. Graph the...Ch. 2 - Calculate the thermal conductivity of air,...Ch. 2 - A method for determining the thermal conductivity...Ch. 2 - Prob. 2.24PCh. 2 - Prob. 2.25PCh. 2 - At a given instant of time, the temperature...Ch. 2 - Prob. 2.27PCh. 2 - Uniform internal heat generation at q.=5107W/m3 is...Ch. 2 - Prob. 2.29PCh. 2 - The steady-state temperature distribution in a...Ch. 2 - The temperature distribution across a wall 0.3 m...Ch. 2 - Prob. 2.32PCh. 2 - Prob. 2.33PCh. 2 - Prob. 2.34PCh. 2 - Prob. 2.35PCh. 2 - Prob. 2.36PCh. 2 - Prob. 2.37PCh. 2 - One-dimensional, steady-state conduction with no...Ch. 2 - One-dimensional, steady-state conduction with no...Ch. 2 - The steady-state temperature distribution in a...Ch. 2 - One-dimensional, steady-state conduction with no...Ch. 2 - Prob. 2.42PCh. 2 - Prob. 2.43PCh. 2 - Prob. 2.44PCh. 2 - Beginning with a differential control volume in...Ch. 2 - A steam pipe is wrapped with insulation of inner...Ch. 2 - Prob. 2.47PCh. 2 - Prob. 2.48PCh. 2 - Two-dimensional, steady-state conduction occurs in...Ch. 2 - Prob. 2.50PCh. 2 - Prob. 2.51PCh. 2 - A chemically reacting mixture is stored in a...Ch. 2 - A thin electrical heater dissipating 4000W/m2 is...Ch. 2 - The one-dimensional system of mass M with constant...Ch. 2 - Consider a one-dimensional plane wall of thickness...Ch. 2 - A large plate of thickness 2L is at a uniform...Ch. 2 - Prob. 2.57PCh. 2 - Prob. 2.58PCh. 2 - A plane wall has constant properties, no internal...Ch. 2 - A plane wall with constant properties is initially...Ch. 2 - Consider the conditions associated with Problem...Ch. 2 - Prob. 2.62PCh. 2 - A spherical particle of radius r1 experiences...Ch. 2 - Prob. 2.64PCh. 2 - A plane wall of thickness L=0.1m experiences...Ch. 2 - Prob. 2.66PCh. 2 - A composite one-dimensional plane wall is of...Ch. 2 - Prob. 2.68PCh. 2 - The steady-state temperature distribution in a...
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- 3. A thin metallic wire of thermal conductivity k, diameter D, and length 2L is annealed by passing an electrical current through the wire to induce a uniform volumetric heat generation åg. The ambient air around the wire is at a temperature To, while the ends of the wire at xarrow_forward2. Heat transfer coefficients can be difficult to measure, particularly for situations involving fast-moving fluids. In some cases however, the magnitude of the heat transfer coefficients can be estimated to a sufficient degree to enable further analysis of the larger problem. In a situation such as that described in the preceding paragraph, heat transfer occurs through the planar wall shown in the figure below. Two thermal situations are to be considered. In case I, the temperature of the fluid to the left of the wall is 130.5 °F and the fluid on the right is at 71.3 °F. Both sides of the planar wall are washed by fast- moving water. The exact values of the convective heat transfer coefficients are unknown. The heat flux through the wall is measured to be 42.6 Btu/hr-ft². 2 inches Tfl h₁ T₁ T₂ T₁² 11₂arrow_forwardDon’t use Heissler charts to answer this question Heat sterilization of lumber, timbers, and pallets is used to kill insects to prevent their transfer between countries in international trade. This is analogous to food sterilization by heat. A typical requirement here is that the slowest heating point of any woodconfiguration be held at 56 °C for 30 minutes. Consider hot air heating of wooden boards that maintains their surface temperature at 70 °C. The boards are stacked outside and in the winter time they can be considered to be at 0 °Cwhen theyare brought in for heating. The thermal diffusivity of the wood is 9*10-8m2/s. a.Calculate the time from the start of heating for a 2.5 cm thick board to reach a sterilization temperature of 56 °C at its slowest heating point .b.Calculate the heating time when four such boards are stacked together. c.Calculate the ratio of the two heating times (for a single board versus when they are stacked), and explain the ratio. Note: You’re free to…arrow_forwardFig. 4 illustrates an insulating wall of three homogeneous layers with conductivities k1, k2, and k3 in intimate contact. Under steady state conditions, both right and left surfaces are exposed to a temperature in a steady state condition at ambient temperatures of T and T , respectively, while ß, and BLare the film coefficients respectively. Assume that there is no internal heat generation and that the heat flow is one-dimensional (dT/dy = 0). For the illustrated ambient temperature in Fig. 4, determine the temperature's distribution at each layer. 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The inner surface of the channel is at a uniform temperature of 600 K and the outer surface is at a uniform temperature of 300 K. From a symmetrical elemental of the channel, a two-dimensional grid has been constructed as in the right figure below. The points are spaced by equal distance. Tout = 300 K k = 1 W/m-K T = 600 K (a) The heat transfer from inside to outside is only by conduction across the channel wall. Beginning with properly defined control volumes, derive the finite difference equations for locations 123. You can also use (n, m) to represent row and column. For example, location Dis (3, 3), location is (3,1), and location 3 is (3,5). (hint: I have already put a control volume around this locations with dashed boarder.) (b) Please use excel to construct the tables of temperatures and finite difference. Solve for the temperatures of each locations. Print out the tables in the spread…arrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_ios
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