Answer Happy

1. In an industry steel pipes are manufactured with the following dimensions. A steel pipe with 5 cm outside diameter is covered with a 6.4 mm asbestos insulation (k - 0.166 W/mK) followed by a 25 mm layer of fibre- glass insulation (k = 0.0485 W/mK). The pipe wall temperature is 393 K and the outside temperature is 311 K. With the aid of a neat diagram, evaluate the interface temperature between the asbestos and fibre- glass. 2. In an industry steel pipes are manufactured with the following dimensions. A steam pipe of outer diameter 120 mm is covered with two layers of lagging inside layer 45 mm thick (k - 0.08 W/m°C) and outside layer 30 mm thick (k = 0.12 W/m°C). The pipe conveys steam at a temperature of 262.4°C. The outside temperature of lagging is 25°C. If the steam pipe is 30 m long, evaluate the following with the aid of neat diagram: a) Heat lost per hour b) Interface temperature of lagging. a 1002022