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).
Want to see more full solutions like this?
Chapter 2 Solutions
Thermodynamics: An Engineering Approach
- A mass of 15 kg of air in a piston–cylinder device is heated from 25 to 95°C by passing current through a resistance heater inside the cylinder. The pressure inside the cylinder is held constant at 300 kPa during the process, and a heat loss of 60 kJ occurs. Determine the electric energy supplied, in kWh.arrow_forwardSteam turbine is receiving a 1,831 lb/hr of steam, determine the kW output of the turbine if the work done by the steam is 1,906 BTU/lb.arrow_forward350 kJ of heat is added in a piston-cylinder arrangement containing air causing it to expand in a polytropic manner. If the polytropic exponent throughout the process is 1.2, determine (a) the change in internal energy (b) the work produced in kJ.arrow_forward
- The force required to expand the gas in a gas spring a distance x is given by F = Constant ________ xk where the constant is determined by the geometry of this device and k is determined by the gas used in the device. Such a gas spring is arranged to have a constant of 1000 N·m1.3 and k = 1.3. Determine the work, in kJ, required to compress this spring from 0.1 m to 0.3 m.arrow_forwardWhen is a system a closed system, and when is it a control volume?arrow_forwardDetermine the energy transferred by conduction in 31 minutes, between the two faces of a concrete wall with an area of 24.2 m ^ 2 and a thickness of 29.2 cm, if inside the temperature is 16 ° C, and outside the temperature is 28.8 ° C. * Express your answer in kJ. I NEED IT RIGHT NOW. I WILL RATE IT, PLEASEEEEarrow_forward
- Determine the Kinetic energy in BTU of a 7 lbm block moving at a velocity of 85 ft/s.arrow_forwardAn adiabatic closed system is accelerated from 0 m/s to 30 m/s. Determine the specific energy change of this system, in kJ/kg.arrow_forwardHow much work, in kJ, can a spring whose spring constant is 3 kN/cm produce after it has been compressed 3 cm from its unloaded length?arrow_forward
- Determine the specific kinetic energy of a mass whose velocity is 30 m/s, in kJ/kg.arrow_forwardA closed system containing gas expands slowly in a piston cylinder from 321.7 psf and 8.2 ft3 to a final volume of 19.5 ft3 . Determine the work done if the pressure distribution is determined to be P2V 2.6 = c.arrow_forwardWhen is work said to be done by a system. Is there any difference between work transfer and heat transfer?arrow_forward
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY