3. An exhaust pipe of 75 mm outside diameter is cool by surrounding it by an annular space containing water. The exhaust

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3 An Exhaust Pipe Of 75 Mm Outside Diameter Is Cool By Surrounding It By An Annular Space Containing Water The Exhaust 1 (21.17 KiB) Viewed 11 times

3. An exhaust pipe of 75 mm outside diameter is cool by surrounding it by an annular space containing water. The exhaust gas enters the exhaust pipe at 350° C and the water enters from the mains at 10°C. The heat transfer coefficients for the gases and water are 0.3 and 1.5 kW m-K. and the pipe thickness may be taken to be negligible. The gases are cool to 100 °C and the mean specific heat capacity at constant pressure is 1.13 kJ kg K. The gas flow rate is 200kg/hr and the water flow rate is 1400 kg h. The specific heat capacity of water is 4.19 kg K. calculate: (i) The required pipe length for parallel-flow: (11) The required pipe length for counter-flow.