Hot air flows from a furnace through a 0.15-m-diameter, thin-walled steel duct with a velocity of 3 m/s. The duct passes through the crawlspace of a house, and its uninsulated exterior surface is exposed to quiescent air and surroundings at 0°C.
(a) At a location in the duct for which the mean air temperature is 70°C, determine the heat loss per unit duct length and the duct wall temperature. The duct outer surface has an emissivity of 0.5.
(b) If the duct is wrapped with a 25-mm-thick layer of 85% magnesia insulation
Want to see the full answer?
Check out a sample textbook solutionChapter 9 Solutions
Fundamentals of Heat and Mass Transfer
Additional Engineering Textbook Solutions
Fluid Mechanics: Fundamentals and Applications
Mechanics of Materials, 7th Edition
Machine Tool Practices (10th Edition)
Vector Mechanics for Engineers: Statics and Dynamics
Shigley's Mechanical Engineering Design (McGraw-Hill Series in Mechanical Engineering)
Applied Statics and Strength of Materials (6th Edition)
- 1.13 If the outer air temperature in Problem is –2°C, calculate the convection heat transfer coefficient between the outer surface of the window and the air, assuming radiation is negligible.arrow_forwarda) What regions show the largest oceanic latent heat loss? b) What regions show the saltiest surface waters? c) What is the main factor affecting the two radiation heat flux terms? Name the two fluxes. d) What is the main factor affecting the two turbulent heat flux terms? Name the two fluxes.arrow_forwardThe small horizontal metal tube with an OD of 0.05 m, 0.1 m long, and with a surface temperature of 25 C is in a very large furnace enclosure with firebrick walls and the surrounding air at 500 C. The emissivity of the metal tube is 0.6. Calculate the net heat transfer to the tube by radiation in Watts.arrow_forward
- A long electrical conductor of 10 mm diameter is concentric with a refrigerated cylindrical tube of 50 mm diameter whose surface has an emissivity of 0.9 and temperature of 27 °C. The electrical conductor has a surface emissivity of 0.6 and dissipates 6.0 W per meter length. Assuming that the space between the two surfaces is empty, calculate the surface temperature of the conductor.arrow_forwardDifferentiate between free and forced convection with examples.arrow_forwardFor the Convective Heat Transfer experiment, describe the difference in the procedures: Natural or FreeConvection and Forced convection. What makes the FORCED convection experiment as FORCED? Explain which, in your consideration should give the higher heat transfer rate? And REASON why? Did your results support your consideration?arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning