Engine oil enters staggered tube array at a temperature of 25°C and at 7 m/s. The tubes have a 15-mm diameter and the tube surface temperature is maintained at 90°C. For the staggered tube array ST = 20 mm and SL = 27 mm, and there are 9 rows of tubes and 8 tubes in each row. What is the total rate of heat transfer to the oil? What is the pressure drop associated with the flow of the oil through the array?