计算流体力学一维稳态导热编程作业

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The Finite Volume Method for One-Dimensional

Diffusion Problems

I. Problem of 1-dimensional Steady-State Source-free Heat Conduction

Consider the problem of source-free heat conduction in an insulated rod whose ends are maintained at constant temperatures of 100℃ and 500℃ respectively. The one-dimensional problem sketched in the Figure 1 is governed by

0=⎪⎭

⎫ ⎝⎛dx dT k dx d Calculate the steady state temperature distribution in the rod. Thermal conductivity k equals 1000W/m/K, cross-sectional area A is 10-2m 2

.

Fig. 1 Physical Model

1网格划分

条件

2

210500100,//1000,

1.05/,5.0m A T T K m W k m L x m L B A -======∆=℃℃,

2方程离散

0.5 m

T B =500

T A =100

Area(A) B

A

求解域内共有5个节点,节点2、3、4的离散方程:

W w WP w E e PE e W P w WP w e PE

T A x k T A x k T T A x k A x k ⋅⎪⎪⎭⎫ ⎝⎛+⋅⎪⎪⎭⎫

⎝⎛+⋅=⋅⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫ ⎝⎛+⎪⎪⎭⎫ ⎝⎛δδδδ0e 由于k k k w e ==,x x x WP Pe δδδ==,A A A W e ==均为常数,因此对节点2、3、4有离散方程:

E E W W P P T a T a T a +=

式中A x k a W δ=

,A x

k a E δ=,E W P a a a +=, 节点1的离散方程:0=---AP

A

P w w PE P E e

e x T T A k x T T A k δδ

A w AP w E e PE e W P w AP w e PE

e T A x k T A x k T T A x k A x k ⋅⎪⎪⎭⎫

⎝⎛+⋅⎪⎪⎭⎫ ⎝⎛+⋅=⋅⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫ ⎝⎛+⎪⎪⎭⎫ ⎝⎛δδδδ0 可写为:u E E W W P P S T a T a T a ++= 其中e PE

e

E A x k a δ=

, 0=W a , P E W P S a a a -+=, w AP

w P A x k

S δ2-=, A w AP w u

T A x k S ⎪⎪⎭

⎫ ⎝⎛=δ2 同理,节点5的离散方程0=---WP

W P w w PB P

B e

e x T T A k x T T A k δδ

B e PB e W w WP w E P e PB e w WP

w T A x k T A x k T T A x k A x k ⋅⎪⎪⎭⎫

⎝⎛+⋅⎪⎪⎭⎫ ⎝⎛+⋅=⋅⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫ ⎝⎛+⎪⎪⎭⎫ ⎝⎛δδδδ0 可写为:u E E W W P P S T a T a T a ++= 其中0=E a , w WP

w

W A x k a δ=

, P E W P S a a a -+=, PB

e

P x k S δ2-

=, B e PB e u T A x k S ⋅⎪⎪⎭

⎫ ⎝⎛=δ2 所以得到各节点的a W , a E , a P , S c , S p 的值

各节点离散方程系数

值 节点

a W a E

S p

S u

a P= a W +a E -S p

1 0

A x k δ A x

k δ2

- A AT x

k

δ2

A x k δ3

2 A x k δ A x k δ 0 0 A x k δ2

3 A x

k δ A x

k δ 0 0 A x k δ2 4 A x

k δ A x k δ 0

A x k δ2 5

A x

k δ 0

A x

k δ2

- B AT x

k

δ2

A x k δ3 即:

值 节点

a W a E S p S u

a P= a W +a E -S p

1 0 100 -200 A T 200

300 2 100 100 0 0 200 3 100 100 0 0 200 4 100 100 0 0

200 5

100

-200

B T 200

300

从而得下述代数方程组 ⎪⎪⎪⎩⎪

⎪⎪⎨⎧+=+=+=+=+=B A T T T T

T T T T T T

T T T T T 200100300100100200100100200100100200200100300455

3442331221 写成矩阵形式有:

⎥⎥⎥⎥⎥⎥⎦⎤⎢

⎢⎢⎢⎣⎡=⎥⎥⎥⎥⎥⎥⎦⎤⎢⎢⎢⎢⎢⎢⎣⎡⎥⎥⎥⎥⎥⎥⎦⎤⎢⎢⎢⎢⎢⎢⎣⎡--------B A T T T T T T T 200000200300100000100200100000100200100000100200100000100

30054321

将500,100

==B A T T 代入,解得此方程组为:

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