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: