An incompressible fluid flows steadily in the entrance region of a circular tube of radius R = 75 mm. The flow rate is Q = 0:1 m3=s. Find the uniform velocity U1 at the entrance. The velocity distribution at a section downstream is u umax = 1− r R 2 Evaluate the maximum velocity at the downstream section. Calculate the pressure drop that would exist in the channel if viscous friction at the walls could be neglected.

On a average work day more than work place firs are reorted

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

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 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?