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In: Mechanical Engineering

Combustion gases passing through a 0.08-m-internal-diameter circular tube are used to vaporize waste water at atmospheric...

Combustion gases passing through a 0.08-m-internal-diameter circular tube are used to vaporize waste water at atmospheric pressure. Hot gases enter the tube at 115 kPa and 250°C at a mean velocity of 5 m/s and leave at 150°C. The average heat transfer coefficient is 120 W/m2·K and the inner surface temperature of the tube is 110°C.

The properties of air at the average temperature of (250+150)/2=200°C are:

cp = 1023 J/kg.°C

R = 0.287 kJ/kg.K

A) Determine the mass flow rate of the exhaust gases in kg/s.

B) The mass flow rate of exhaust gases is 0.019256706 kg/s. Determine the rate of heat transfer.

C) The rate of heat transfer is 1969.961058 W. Determine the surface area of the underwater duct.

D) The surface area of an underwater duct is 0.205657855 m2. Determine the tube length.

E) Find the rate of evaporation of water. [kg/hr]

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