Calculate the temperatures of the inside and outside surfaces of the metal pipe or tubing in cases 1 to 3 of Prob. 11.1.

Cases 1 to 3 of Prob. 11.1

Calculate the overall heat-transfer coefficients based on both inside and outside areas for the following cases. 

Case 1    Water at 10°C flowing in a ³/₄-in. 16 BWG condenser tube and saturated steam at 105°C condensing on the outside. h_i = 12 kW/m² · °C. h_∘ = 14 kW/m²∙°C. k_m = 120 W/m · °C. 

Case 2    Benzene condensing at atmospheric pressure on the outside of a 25-mm steel pipe and air at 15°C flowing within at 6 m/s. The pipe wall is 3.5 mm thick. h_i = 20 W/m²  · °C. h_∘ = 1.200 W/m² · °C. k_m = 45 W/m · °C. 

Case 3    Dropwise condensation from steam at a pressure of 50 lb_ƒ/in.² gauge on a 1-in. Schedule 40 steel pipe carrying oil at 100°F, h_∘ = 14,000 Btu/ft² · h · °F.  h_i =130 Btu/ft² · h · °F. k_m = 26 Btu/ft · h · °F.