Dry steam at 4 bars absolute pressure with a mean velocity of 3 m/s enters a horizontal pipe with inner and outer diameters of 55 and 65 mm, respectively. the heat transfer coefficient for the steam flow is known to be 11,000 w/m2*k. the outside of the steam pipe is covered with a 25-mm-thick layer of 85% magnesia insulation and is exposed to atmospheric air at 25 °c.
1. determine the rate of heat transfer by free convection to the room per unit length of the pipe.
2. determine the quality of the steam at the exit of a 30-meter-long section of pipe.