Atube bank uses an aligned arrangement of 10-mm-diameter tubes with st = sl = 20 mm. there are 10 rows of tubes with 50 tubes in each row. consider an application for which cold water flows through the tubes, maintaining the outer surface temperature at 27°c, while flue gases at 427°c and a velocity of 5 m/s are in cross flow over the tubes. the properties of the flue gas may be approximated as those of atmospheric air at 427°c. what is the total rate of heat transfer per unit length of the tubes in the bank?