Steam at 180 0 C flows in a circular pipe, which is composed of 3 different materials (A, B and C). The pipe is located in a room at 20 0 C. Convection heat transfer coefficient between the steam and...

Extracted text: Steam at 180 °C flows in a circular pipe, which is composed of 3 different materials (A, B and C). The pipe is located in a room at 20 °C. Convection heat transfer coefficient between the steam and the inner surface of the wall is 27.777 W/m2K. Convection and radiation heat transfer coefficient between the outer surface of the pipe and the air are 7 and 3 W/m?K, respectively. Thermal resistances of the layers are Ra=0.02 °C/W, R3=0.03 °C/W and Rc=0.08 °C/W. The inner and the outer surface area of the pipe are A, =1.8 and A4=2 m2 respectively. What is the temperature at interface 3? Tout=20 °C hout.conv=10 W/m²K hout.rad=5 W/m²K Tin=180 °C\A h=27.777 W/m?K 2 4 r,=5 cm r2=5.5 cm r3=6 cm r4=6.33 cm О а. 142 °с ОБ. 124 °С Ос. 138 °C O d. 134 °C Ое. 130 °с