Water is to be heated from 10°C to 80°C as it flows through a 2 cm internal diameter, 13 m long tube. The average flow rate of water is 5 L/min. Find average velocity of water and the convection heat transfer coefficient. The water is heated using an electric resistance heater (in the tube) which provides uniform heating throughout the surface of the tube. The outer diameter of the tube is well insulated, such that in steady operation all the heat generated in the heater is transferred to the water in the tube. Assume turbulent flow for Re > 5000 for this problem

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.