A one-shell, two-tube pass shell and tube heat exchanger has 1580 tubes with d i = 13 mm and do = 16

A one-shell, two-tube pass shell and tube heat exchanger has
1580 tubes with di = 13 mm and do = 16 mm. Tubes have an average
length of 6 m per pass. Cold water enters the tubes at 30 C and a rate of 110
kg/s and hot water enters shell at 90 C and a rate of 125 kg/s. Find the rate
of heat transfer, _TLMTD, and the overall heat transfer coefficient. Use
stainless steel tubes and fi = 0.001 m2 ·K/W.