Steam in a heating system flows through tubes whose outer diameter is 3 cm and whose walls are maintained at a temperature of 120°C. Circular aluminum alloy fins (k = 180 W/m·K) of outer diameter 6 cm and constant thickness t = 2 mm are attached to the tube, as shown in Fig. P17€“130. The space between the fins is 3 mm, and thus there are 200 fins per meter length of the tube. Heat is transferred to the surrounding air at 25°C, with a combined heat transfer coefficient of 60 W/m²·K. Determine the increase in heat transfer from the tube per meter of its length as a result of adding fins.

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4= 1.5 cm 2= 3 cm t= 2 mm S= 3 mm