Heat Transfer #$1$

An engineer is designing a multiple$-$tube heating system that is placed in a duct

with air supply to the building. He decides to carry out a preliminary test using one

$2$ cm copper tube carrying the condensed steam at $100C.$ The velocity of air in the

duct is $5\frac{m}{s}$ with temperature of $20C.$ The tube can be placed perpendicular to

the flow, but because of the additional heat transfer surface area it may be

advantageous to tilt the tube to the airflow. When the duct has a width of $1$ m $,$

determine the outcome of the planned tests.