Steam in a heating system flows through tubes whose outer diameter is D1 =3 cm and whose walls are maintained at a temperature of 120°C. Circular aluminum fins (k =

180W/m.°C) of outer diameters D2 = 6 cm and constant thickness t = 2mm are attached to the tubes. The space between the fins is 3 mm. Heat is transferred to the surrounding air at T = 25 °C, with a convection heattransfer coefficient of h = 60 W/m2.°C Determine the number of fins per meter length Determine the increase in heat transfer from the tube per meter of its length as a result of adding fins.2-