ASSIGNMENT ONE QUESTION ONE a) A 250mm steam main, 225metres long is covered with 50mm of high temperature insulation (k = 0.095W/m K) and 40 mm of low temperature insulation (k = 0.065W/m K). The inner and outer surface temperatures as measured are 400°C and 50°C respectively. Calculate : (i) The total heat loss per hour. [5] (ii) The total heat loss per m2 of outer surface. [5] (iii) The heat loss per m2 of pipe surface. [4] (iv) The temperature between the two layers of insulation. [4] Neglect heat conduction through pipe material b) A steam pipe of 160 mm inside diameter and 170 mm outside diameter (k = 58 W/m K) is covered with first layer of insulating material of 30 mm thickness (k = 0.17 W/m K) and second layer of insulating material of 50 mm thickness (k = 0.093 W/m K). The temperature of steam passing through the pipe is 300°C and ambient air temperature surrounding the pipe is 30°C. Taking inner and outer heat transfer co-efficients 30 and 5.8 W/m2 K respectively, find the heat lost per metre length of pipe. [7]
