Ahorizontal pipe of 5 cm diameter conveys an oil of specific gravity 0.9 and dynamic viscosity 0.8 kg/ms measurement indicates a pressure drop of 20 kn/m2 per meter of pipe length traversed. calculate the following (3.1), the flow rate of the oil and the centre line velocity (3.2), the wall shear stress (3.3). the frictional drag over 100 m of pipe length, (3.4). the power of the pump required assuming an overall efficiency of 60%, (3.5), the velocity at 1 cm from the pipe surface and (3.6), the shear stress ant also at 1 from the pipe wall.

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.