The plotting of rate of heat transfer against the convection heat transfer coefficient for the surface emissivities of 0.1, 0.5, 0.8, and 1. Also, discuss the results.
Answer to Problem 100P
The plotting of rate of heat transfer against the convection heat transfer coefficient for the surface emissivities of 0.1, 0.5, 0.8, and 1 are shown in Figure (1) and results are discussed as below.
Explanation of Solution
Calculate the rate of heat transfer by convection.
Here, change in the temperature is
Calculate the rate of heat transfer by radiation.
Here, surface temperature is
Calculate the total rate of heat transfer from the ball.
Conclusion:
Let us solve for
Substitute
Substitute
Substitute 34.35 W for
Follow the above process to calculate the rate of heat transfer against the convection heat transfer coefficient for the surface emissivities of 0.1 and 0.5 using spreadsheet including equations (I), (II), and (III) as in table (1).
5 | 11.4511 | 2.04127 | 13.4924 | 10.2064 | 21.6575 |
7.5 | 17.1767 | 2.04127 | 19.2179 | 10.2064 | 27.383 |
10 | 22.9022 | 2.04127 | 24.9435 | 10.2064 | 33.1086 |
12.5 | 28.6278 | 2.04127 | 30.669 | 10.2064 | 38.8341 |
15 | 34.3533 | 2.04127 | 36.3946 | 10.2064 | 44.5597 |
17.5 | 40.0789 | 2.04127 | 42.1201 | 10.2064 | 50.2852 |
20 | 45.8044 | 2.04127 | 47.8457 | 10.2064 | 56.0108 |
22.5 | 51.53 | 2.04127 | 53.5712 | 10.2064 | 61.7363 |
25 | 57.2555 | 2.04127 | 59.2968 | 10.2064 | 67.4619 |
27.5 | 62.9811 | 2.04127 | 65.0224 | 10.2064 | 73.1874 |
30 | 68.7066 | 2.04127 | 70.7479 | 10.2064 | 78.913 |
Continue table (1) for
16.3302 | 27.7813 | 20.4127 | 31.8638 |
16.3302 | 33.5068 | 20.4127 | 37.5894 |
16.3302 | 39.2324 | 20.4127 | 43.3149 |
16.3302 | 44.9579 | 20.4127 | 49.0405 |
16.3302 | 50.6835 | 20.4127 | 54.766 |
16.3302 | 56.4091 | 20.4127 | 60.4916 |
16.3302 | 62.1346 | 20.4127 | 66.2172 |
16.3302 | 67.8602 | 20.4127 | 71.9427 |
16.3302 | 73.5857 | 20.4127 | 77.6683 |
16.3302 | 79.3113 | 20.4127 | 83.3938 |
16.3302 | 85.0368 | 20.4127 | 89.1194 |
Show the plotting of rate of heat transfer against the convection heat transfer coefficient for the surface emissivities of 0.1, 0.5, 0.8, and 1.0 using Table (1) and (2) as in Figure (1).
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Chapter 2 Solutions
EBK THERMODYNAMICS: AN ENGINEERING APPR
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- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning