QUESTION $1[15$ MARKS$]$

A metal rod, initially at a uniform temperature of $80C,$ is placed in an open environment at $20C$ with a fan blowing air across the rod's surface. Over time, the temperature of the rod decreases due to various modes of heat transfer.

a$)$ Explain in detail all modes of heat transfer involved as the rod cools as shown in Figure $1.$ Include a description of each mode and how it contributes to the cooling process.

$[5$ Marks$]$

$[$CO$1,$ PO$1,$C$3]$

b$)$ Suggest methods to enhance the cooling process of the rod for each heat transfer mode. Justify your suggestions with relevant heat transfer parameters and principles.

$[5$ Marks$]$

$[$CO$1,$ PO$1,$C$3]$

c$)$ Calculate the heat loss rate due to convection, if the convective heat transfer coefficient between the rod's surface and the surrounding air is $h=15\frac{W}{m^2}*K.$ Consider the rod has a surface area of $A=0\mathrm{.}2m^2.$ Use the initial temperature difference to estimate the convective heat loss.

$[5$ Marks$]$

$[$CO$1,$ PO$1,$C$3]$