contestada

A pipe of 0.3 m outer diameter at a temperature of 160°C is insulated with a material having a thermal conductivity of k = 0.055 (1 + 2.8 × 10–3T) W/mK where T is in °C. The outside surface temperature is 40°C. Determine the heat flow/m length and the temperature at the mid radius

Respuesta :

Answer:

Q=0.95 W/m

Explanation:

Given that

Outer diameter = 0.3 m

Thermal conductivity of material

[tex]K= 0.055(1+2.8\times 10^{-3}T)\frac{W}{mK}[/tex]

So the mean conductivity

[tex]K_m=0.055\left ( 1+2.8\times 10^{-3}T_m \right )[/tex]

[tex]T_m=\dfrac{160+273+40+273}{2}[/tex]

[tex]T_m=373 K[/tex]

[tex]K_m=0.055\left ( 1+2.8\times 10^{-3}\times 373 \right )[/tex]

[tex]K_m=0.112 \frac{W}{mK}[/tex]

So heat conduction through cylinder

[tex]Q=kA\dfrac{\Delta T}{L}[/tex]

[tex]Q=0.112\times \pi \times 0.15^2\times 120[/tex]

Q=0.95 W/m

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