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analysis of transient heat conduction in different geometries - ethesis ...

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Differentiat<strong>in</strong>g the above equation with respect to x we get<br />

Apply<strong>in</strong>g first boundary condition we have<br />

∂ θ<br />

= a1+ 2a2x<br />

∂ x<br />

a1+ 2a2x= 0<br />

(3.112)<br />

Thus<br />

a 1 = 0<br />

(3.113)<br />

Apply<strong>in</strong>g second boundary condition we have<br />

Thus<br />

a + 2a<br />

=−Bθ<br />

1 2<br />

a<br />

2<br />

Bθ<br />

=−<br />

2<br />

We can also write the second boundary condition as<br />

Us<strong>in</strong>g the above expression we have<br />

Average temperature for long slab can be written as<br />

37<br />

(3.114)<br />

(3.115)<br />

∂ θ<br />

=− B( a0 + a1+ a2)<br />

∂ x<br />

(3.116)<br />

⎛ B ⎞<br />

a0 = θ ⎜1+ ⎟<br />

⎝ 2 ⎠ (3.117)<br />

1<br />

0 dx<br />

θ θ = ∫<br />

Substitut<strong>in</strong>g the value <strong>of</strong> θ and <strong>in</strong>tegrat<strong>in</strong>g we have<br />

Bθ<br />

θ = θ +<br />

3<br />

Integrat<strong>in</strong>g non-dimensional govern<strong>in</strong>g equation we have<br />

(3.118)

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