Two-dimensional Steady State Heat Consuction

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7/23/2019 Two-dimensional Steady State Heat Consuction http://slidepdf.com/reader/full/two-dimensional-steady-state-heat-consuction 1/4 Two-Dimensional Steady State Heat Conduction in a Rectangular Plate G.E : B.C Solution : Method of Separation of Variables  Assume Solution of the form T 1  , θ= 0 T 1  , θ= 0  x a b T 2  , θ= 1 T 1  , θ= 0 2 2 2 2 0  x y θ θ + = (0, ) 0; ( , ) 0 ( ,0) 0; ( , ) 0  y a y  x x b θ θ θ θ = = = =  y 2  (, ) () ( ) "( ) "( ) G.E where constant () ( )  x y F x G y  F x G y  F x G y θ λ λ =   − = = =

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Two-Dimensional Steady State Heat

Conduction in a Rectangular Plate

G.E :

B.C

Solution : Method of Separation of Variables Assume Solution of the form

T1 ,

θ= 0

T1 , θ= 0  x

a

b

T2 , θ= 1

T1 , θ= 0

2 2

2 20

 x y

θ θ ∂ ∂+ =

∂ ∂

(0 , ) 0 ; ( , ) 0( , 0 ) 0 ; ( , ) 0

 y a y x x b

θ θ 

θ θ 

= =

= =

 y

2

  ( , ) ( ) ( )

"( ) "( )G.E where constant( ) ( )

 x y F x G y

 F x G y

 F x G y

θ 

λ λ 

=

∴   ⇒ − = = =

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Two-Dimensional Steady State Heat

Conduction in a Rectangular Plate

( )( )

( )

( )

1 2

3 4

1 2 3 4

1

2 3 4

3 4

2 4

2

cos sin

cos sin

(0, ) 0 0

( ,0) 0 sin 0

 

( , ) 0 sin 0

  sin 0 / for 1,2,3,

 y y

 y y

 y y

 F C x C x

G C e C e

C x C x C e C e

 y C 

 x C x C C 

C C 

a y C C a e e

a n a

λ λ 

λ λ 

λ λ 

λ λ 

θ λ λ 

θ 

θ λ 

θ λ 

λ λ π λ  

θ 

= +

= +

= + +

=   ⇒   =

=   ⇒   + =

⇒   = −

=   ⇒   − =

⇒   =   ⇒   = =

=…

( )/ /

4 sin / sin( / )sinh( / )n y a n y a

nC n x a e e C n x a n y aπ π π π π 

−− =

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Two-Dimensional Steady State Heat

Conduction in a Rectangular Plate

( )

( )( )

1

1

1

2

0 0

sin( / ) sinh( / )

( , ) 1 sin sinh 1

2

0 0

sin ; sin 1 cos2

1 cos2sinh /

sin sinh sin

n

n

nn

n

a a

n

C n x a n y a

n x n b x b

a a

a a

n

n x a n x adx dx n

a a n

nC n n b a

n x n b n xC dx

a a a

θ π π 

π π θ 

π π π 

π 

π π π 

π π π 

=

=

=

=

=   ⇒   =

= = −

−=

=∑ ∫ ∫

∫ ∫

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w ( )

( )

( ) ( )

( )

( ) ( )

( )

( )( ) ( )( )

1

0

1 cos2sin sinhsinh /

sin / sinh / sin 3 / sinh 3 /4

sinh / 3sinh 3 /

cosh / 1 cosh 3 / 14 1..........

sinh / 3 sinh 3 /

n

b

 x a

n   n x n y

n n b a a a

 x a y a x a y a

b a b a

T q k dy x

b a b ak q

b a b a

π    π π 

θ  π π 

π π π π  

θ  π π π 

π π 

π π π 

=

=

=

= + +

∂ = − ∂

− −

= + +

Two-Dimensional Steady State Heat

Conduction in a Rectangular Plate