A long 20 cm diameter shaft made of stainless steel 304 comes out of an oven at a uniform temperature of 600°C. The shaft is then allowed to cool slowly in an environment at 200°C with an average heat transfer coefficient of h = 80 W/m²-K. Determine [a] the temperature at the center of the shaft and [b] the temperature of the outer surface of the shaft 45 minutes after the start of the cooling

A long 20 cm diameter shaft made of stainless steel 304 comes out of an oven at a uniform temperature of 600°C. The shaft is then allowed to cool slowly in an environment at 200°C with an average heat transfer coefficient of h = 80 W/m²-K. Determine [a] the temperature at the center of the shaft and [b] the temperature of the outer surface of the shaft 45 minutes after the start of the cooling

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.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.60P: 1.60 Two electric resistance heaters with a 20 cm length and a 2 cm diameter are inserted into a...

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1.60 Two electric resistance heaters with a 20 cm length and a 2 cm diameter are inserted into a well-insulated 40-L tank of water that is initially at 300 K. If each heater dissipates 500 W, what is the time required for bringing the water temperature in the tank to 340 K? State your assumption for your analysis.
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A pipe in a manufacturing plant is transporting superheated vapor at a mass flow rate of 0.3 kg/s. The pipe is 10 m long and has an inner diameter of 5 cm and a wall thickness of 6 mm. The pipe has a thermal conductivity of 17 W/m⋅K, and the inner pipe surface is at a uniform temperature of 120° C. The temperature drop between the inlet and exit of the pipe is 7° C, and the constant pressure specific heat of vapor is 2 190 J/kg⋅°C. If the air temperature in the manufacturing plant is 25° C, determine the heat transfer coefficient as a result of convection between the outer pipe surface and the surrounding air.