Question

A long metal cylindrical shaft at temperature of 200C is allowed to cool slowly to 25C in an

environment with convection heat transfer coefficient (h). It is required to investigate the effect of the cooling time on the shaft temperature and the amount of heat transfer:

Let the time vary from 1 second to 2000 second. Plot the shaft temperature and the amount of heat transfer as a function of the time, and discuss the result.

Notes:

• Use table (A-3) for obtaining the properties of the metal listed below.

• Use any software (Excel for instance)

Material: Gold

L= 1 m

D= 10 cm

h= 19

k= 317

density (p) = 19300

cp= 129

alpha (x) = 127x10^-6

Answer 1