k=14.9

A stainless steel (AISI 304, properties as per Table A-1) tube used to transport chilled water has an internal diameter of 36 mm and a wall thickness of 2 mm. The chilled water and the ambient air are at a temperature of 7 C and 27 C, respectively, while the corresponding inner and outer convection heat transfer coefficients are 400 W/mK and 6 W/ mK Question 2 (a) What is the heat gain per unit tube length if a 10 mm thick layer of insulation (k = 0.05W/mK) i applied to the tube? (3) (b) What is the overall heat transfer coefficient of the insulated tube, based on the inside surface area? Ignore radiation? (3) (c) What is the temperature of the outside surface of the insulation? Ignore radiation? (2) (d) If radiation on the outside of the insulated pipe (emissivity of the insulation = 0.8 and the radiation heat transfer coefficient = 5.34 W m2 K) is to be taken into account and the surroundings walls are at the same temperature as the air, give the thermal resistance diagram and calculate the heat gain. Explain the