PROBLEM 7: 4-58 A long iron rod (p = 7870 kg/m³, cp = 447 J/kg-K, k= 80.2 W/m-K, and a = 23.1 x 10-6 m²/s) with diameter of 25 mm is initially heated to a uniform temperature of 700°C. The iron rod is then quenched in a large water bath that is maintained at constant temperature of 50°C and convec- tion heat transfer coefficient of 128 W/m².K. Determine the time required for the iron rod surface temperature to cool to 200°C. Solve this problem using analytical one-term approxi- mation method (not the Heisler charts). Water, 50°C h = 128 W/m².K Iron rod What is the Biot Number Bi? Is the lumped body analysis valid?

PROBLEM 7: 4-58 A long iron rod (p = 7870 kg/m³, cp = 447 J/kg-K, k= 80.2 W/m-K, and a = 23.1 x 10-6 m²/s) with diameter of 25 mm is initially heated to a uniform temperature of 700°C. The iron rod is then quenched in a large water bath that is maintained at constant temperature of 50°C and convec- tion heat transfer coefficient of 128 W/m².K. Determine the time required for the iron rod surface temperature to cool to 200°C. Solve this problem using analytical one-term approxi- mation method (not the Heisler charts). Water, 50°C h = 128 W/m².K Iron rod What is the Biot Number Bi? Is the lumped body analysis valid?

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter3: Transient Heat Conduction

Section: Chapter Questions

Problem 3.36P

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