Steel ball bearings (k = 50 W/m K, a = 1.3 x 105 m²/s) having a diameter of 40 mm are heated to a temperature of 650°C and then quenched in a tank of oil at " T = Last 2 digits of Student ID Number" °C. If the heat transfer coefficient between the ball bearings and oil is 300 W /m ² K. Determine: (a) the duration of time the bearings must remain in oil to reach a temperature of 200°C (b) the total amount of heat removed from each bearing during this time and (c) the instantaneous heat transfer rate from the bearings when they are first immersed in oil and when they reach 200°C.

Steel ball bearings (k = 50 W/m K, a = 1.3 x 105 m²/s) having a diameter of 40 mm are heated to a temperature of 650°C and then quenched in a tank of oil at " T = Last 2 digits of Student ID Number" °C. If the heat transfer coefficient between the ball bearings and oil is 300 W /m ² K. Determine: (a) the duration of time the bearings must remain in oil to reach a temperature of 200°C (b) the total amount of heat removed from each bearing during this time and (c) the instantaneous heat transfer rate from the bearings when they are first immersed in oil and when they reach 200°C.

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.

Chapter7: Forced Convection Inside Tubes And Ducts

Section: Chapter Questions

Problem 7.29P

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