Fundamentals of Heat and Mass Transfer
Fundamentals of Heat and Mass Transfer
7th Edition
ISBN: 9780470501979
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 2.41P

(a)

To determine

Whether the prescribed temperature distribution possible or not along with an explanation.

The temperature distribution is not possible as the conduction and convection heat transfer is not possible.

Given:

The given diagram is shown in Figure 1.

  Fundamentals of Heat and Mass Transfer, Chapter 2, Problem 2.41P

Figure 1

The thermal conductivity of the wall is k=4.5W/mK .

The steady state temperature of the wall is T=20°C .

The thickness of the wall is L=0.018m .

The convection heat transfer of the wall is h=30W/m2K .

Formula Used:

The expression for the energy balance equation for the steady flow is given by,

  qcondqconv=0

The expression for the conduction heat transfer per unit area is given by,

  qcond=k(TLT0)L

Here, TL is the thickness of the wall at complete thickness of the wall and T0 is the temperature of the wall at 0m .

The expression for the convection heat transfer per unit area is given by,

  qconv=k(TLT)

Calculation:

The conduction heat transfer per unit area is calculated as,

  qcond=k( T L T )L=(4.5W/mK)( 120°C0°C)0.18m=3000W/m2

The convection heat transfer per unit area is calculated as,

  qconv=k(TLT)=30W/m2K(120°C20°C)=3000W/m2

The energy balance equation is calculated as,

  qcondqconv=03000W/m23000W/m2=06000W/m20

The temperature distribution is not possible as the value of conduction and convection heat transfer is not equal.

Conclusion:

Therefore, the temperature distribution is not possible as the conduction and convection heat transfer is not possible.

(b)

To determine

The computation and the plot of the temperature at x=L , T(L) as a function of h for 10h100W/m2K along with an explanation of the results.

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Chapter 2 Solutions

Fundamentals of Heat and Mass Transfer

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