Steam in a heating system flows through a 1-m long tube whose outer diameter is D1 = 3 cm and whose walls are maintained at a temperature of Tb = 120 °C. Circular fins (k = 46 W/m. °C) of outer...

Steam in a heating system flows through a 1-m long tube whose outer diameter is D1 = 3 cm and
whose walls are maintained at a temperature of Tb = 120 °C. Circular fins (k = 46 W/m. °C) of outer diameter D2 = 6 cm and constant thickness t = 2 mm are attached to the tube, as shown in the figure. 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 Tꚙ = 20 °C, with a combined heat transfer coefficient of h = 90 W/m2. °C. Determine:
a. No fin area: Ano fin = ____ m2
b. Unfin area: Aunfin = ____ m2
c. Fin area: Afin = _______ m2


d. Fin efficiency = ______
e. Qno,fin = ______ W
f. Qtotal, fin = ______ W
g. Overall fin effectiveness =