Radioactive wastes are temporarily stored in a spherical container, the center of which is buried a distance of 10 m below the earth's surface. The outside diameter of the container is 2 m, and 500 W of heat are released as a result of radioactive decay. If the soil surface temperature is 20°C, what is the outside surface temperature of the container under steady-state conditions? The thermal conductivity of soil is k = 0.52 W/mK.

Respuesta :

Given:

outer radius, R' = 10 m

inner diameter, d = 2 m

inner radius, R = [tex]\frac{d}{2}[/tex] = 1 m

surface temperature, T' = [tex]20^{\circ}C[/tex]

Thermal conductivity of soil, K = 0.52 W/mK

Solution:

To calculate the thermal temperature of conductor, T, we know amount of heat, Q is given by :

Q =  [tex]\frac{T - T'}{\frac{R' - R}{4\pi KRR'}}[/tex]

500 =  [tex](T - 20)\frac{4\pi \times0.52\times 1\times 10}{10 - 1}[/tex]

T = 68.86 +20 = [tex]88.865^{\circ}C[/tex]  

Therefore, outside surface temperature is [tex]88.865^{\circ}C[/tex]  

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