External Forced Convection Flow Across Tube Bank Example Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20 C. Air approaches the tube bank in the normal direction at 0C and 1 atm with a mean velocity of 4 m/s. The tubes are arranged in-line with longitudinal and transverse pitches of S = ST= 1.5 cm. There are 30 rows in the flow direction with 15 tubes in each row. Determine: (a) Refrigeration capacity of this system (b) Pressure Drop across the tube bank. Mechanical Engineering 0C 1 atm 4 m/s Air ST= 1.5 cm 0.8 cm 0.4 m SL = 1.5 cm Refrigerant, -20C