Water is to be heated from 15°C to 65°C as it flows through a 3-cm-internal-diameter 5-m-long tube. The tube is equipped with an electric resistance heater that provides uniform heating throughout the surface of the tube. The outer surface of the heater is well insulated, so in steady operation, all the heat generated in the heater is transferred to the water in the tube. If the system is to provide hot water at a rate of 10 L/min, determine the power rating of the resistance heater. Also estimate the inner surface temperature of the tube at the exit

Water is to be heated from 15°C to 65°C as it flows through a 3-cm-internal-diameter 5-m-long tube. The tube is equipped with an electric resistance heater that provides uniform heating throughout the surface of the tube. The outer surface of the heater is well insulated, so in steady operation, all the heat generated in the heater is transferred to the water in the tube. If the system is to provide hot water at a rate of 10 L/min, determine the power rating of the resistance heater. Also estimate the inner surface temperature of the tube at the exit

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter7: Forced Convection Inside Tubes And Ducts

Section: Chapter Questions

Problem 7.4P

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Water is to be heated from 15°C to 65°C as it flows through a 3-cm-internaldiameter 5-m-long tube . The tube is equipped with an electric resistance heater that provides uniform heating throughout the surface of the tube. The outer surface of the heater is well insulated, so that in steady operation all the heat generated in the heater is transferred to the water in the tube. If the system is to provide hot water at a rate of 10 L/min, determine the power rating of the resistance heater. Also, estimate the inner surface temperature of the tube at the exit.
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 tube is equipped with an electric resistance heater, which provides uniform heating throughout the surface of the tube. The outer surface of the heater is well insulated, so that in steady operation all the heat generated in the heater is transferred to the water in the tube. If the system is to provide hot water at a rate of 5 L/min, determine the power rating of the resistance heater. Also, estimate the inner surface temperature of the pipe at the exit.
Water is to be heated from 15C to 65 C as it flows through a 3 cm internal diameter 5 m long tube. The tube is equipped with an electric resistance heater that provides uniform heating throughout the surface of the tube. The outer surface of the heater is well insulated, so that in steady operation all the heat generated in the heater is transferred to the water in the tube. If the system is to provide hot water at a rate of 10 L/min, determine the power rating of the resistance heater. Also, estimate the inner surface temperature of the tube at the exit. The water properties at the bulk mean temperature are: density=992.1 kg/m3, k = 0.631 W/m.K, v= 0.658 x 10* m^2/s, Cp = 4.179 kJ/kg. K, Pr = 4.32.
Hot water is flowing at an average velocity of1.5 m/s through a cast iron pipe (k = 52 W/m·K) whose innerand outer diameters are 3 cm and 3.5 cm, respectively. Thepipe passes through a 15-m-long section of a basement whosetemperature is 15°C. If the temperature of the water dropsfrom 70°C to 67°C as it passes through the basement and theheat transfer coefficient on the inner surface of the pipe is400 W/m2·K, determine the combined convection and radiationheat transfer coefficient at the outer surface of thepipe.
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Determine the length of the pipe required to cool the pasteurized orange juice from 65 to 22 °C at a rate of 1500 kg/hr in a 3 cm diameter pipe . The stream of chilled water is flowing from 4 to 20 °C, against the direction of the orange juice. The overall coefficient of heat transfer from the water to the orange juice is 900 J/m2s °C and the specific heat of the orange juice is is 3890 J/kg °C .