Respuesta :
Answer:
The value of heat transferred watt per foot length Q = 54.78 Watt per foot length.
Explanation:
Diameter of pipe = 2 in = 0.0508 m
Steam temperature [tex]T_{1}[/tex] = 300 F = 422.04 K
Duct temperature [tex]T_{2}[/tex] = 70 F = 294.26 K
Emmisivity of surface 1 = 0.79
Emmisivity of surface 2 = 0.276
Net emmisivity of both surfaces ∈ = 0.25
Stefan volazman constant [tex]\sigma[/tex] = 5.67 × [tex]10^{-8}[/tex] [tex]\frac{W}{m^{2} K^{4} }[/tex]
Heat transfer per foot length is given by
Q = ∈ [tex]\sigma[/tex] A ( [tex]T_{1}^{4} - T_{2} ^{4}[/tex] ) ------ (1)
Put all the values in equation (1) , we get
Q = 0.25 × 5.67 × [tex]10^{-8}[/tex] × 3.14 × 0.0508 × 1 × ( [tex]422.04^{4} - 294.26^{4}[/tex] )
Q = 54.78 Watt per foot.
This is the value of heat transferred watt per foot length.
