请高人指点：热量为什么不向外扩散？

双城记2

本人最近做了一个例子，模拟冻结管冻结土体的过程。问题是不论冻结管的温度有多低或时间有多长，其冻结效果就是冻结管周边一点点，冻结范围不向外扩散，不知是怎么回事，请教高手帮我看看。期待您的回应！
源程序如下：

finish
/clear
/filname,0511,1
/title,rec
/prep7
et,1,plane55
!mptemp,1,-27,23          !定义材料1---土体属性
!mpdata,c,1,1,2.54,3.345
MP,C,1,2.3

mptemp,1,-27,23
mpdata,kxx,1,1,2.12,1.42
mptemp,1,-27,23
mpdata,dens,1,1,1528,1910
mptemp,1,-27,-1.4,0,23
mpdata,enth,1,1,0,5.525e4,1.782e5,2.50e5
outres,,all
mp,dens,2,1200         !定义材料2--冻结管属性
mp,c,2,2.500
mp,kxx,2,2.500

k,1,0,5.748,0          !定义46根冻结管   
k,2,-0.699,5.693,0
k,3,-1.391,5.589,0
k,4,-2.070,5.417,0
k,5,-2.728,5.179,0
k,6,-3.359,4.877,0
k,7,-4.040,4.457,0
k,8,-4.710,4.062,0
k,9,-5.238,3.400,0
k,10,-5.78,2.72,0
k,11,-6.231,1.997,0
k,12,-6.543,1.165,0
k,13,-6.762,0.339,0
k,14,-6.669,-0.661,0
k,15,-6.522,-1.569,0
k,16,-6.296,-2.45,0
k,17,-5.849,-3.275,0
k,18,-5.239,-3.963,0
k,19,-4.466,-4.463,0
k,20,-3.612,-4.804,0
k,21,-2.732,-5.071,0
k,22,-1.832,-5.264,0
k,23,-0.919,-5.379,0
k,24,0,-5.418,0
k,25,0.919,-5.279,0
k,26,1.832,-5.264,0
k,27,2.732,-5.071,0
k,28,3.612,-4.804,0
k,29,4.466,-4.463,0
k,30,5.239,-3.963,0
k,31,5.849,-3.275,0
k,32,6.269,-2.45,0
k,33,6.522,-1.569,0
k,34,6.669,-0.661,0
k,35,6.692,0.259,0
k,36,6.543,1.165,0
k,37,6.251,1.977,0
k,38,5.780,2.72,0
k,39,5.238,3.4,0
k,40,4.669,3.962,0
k,41,4.04,4.457,0
k,42,3.359,4.877,0
k,43,2.728,5.179,0
k,44,2.07,5.417,0
k,45,1.391,5.589,0
k,46,0.699,5.693,0

circle,1,0.1
circle,2,0.1
circle,3,0.1
circle,4,0.1
circle,5,0.1
circle,6,0.1
circle,7,0.1
circle,8,0.1
circle,9,0.1
circle,10,0.1
circle,11,0.1
circle,12,0.1
circle,13,0.1
circle,14,0.1
circle,15,0.1
circle,16,0.1
circle,17,0.1
circle,18,0.1
circle,19,0.1
circle,20,0.1
circle,21,0.1
circle,22,0.1
circle,23,0.1
circle,24,0.1
circle,25,0.1
circle,26,0.1
circle,27,0.1
circle,28,0.1
circle,29,0.1
circle,30,0.1
circle,31,0.1
circle,32,0.1
circle,33,0.1
circle,34,0.1
circle,35,0.1
circle,36,0.1
circle,37,0.1
circle,38,0.1
circle,39,0.1
circle,40,0.1
circle,41,0.1
circle,42,0.1
circle,43,0.1
circle,44,0.1
circle,45,0.1
circle,46,0.1
rectng,-9.92,9.92,-8.66,13.75   !建立矩形
al,1,2,3,4                      !建46根冻结管
al,5,6,7,8
al,9,10,11,12
al,13,14,15,16
al,17,18,19,20
al,21,22,23,24
al,25,26,27,28
al,29,30,31,32
al,33,34,35,36
al,37,38,39,40
al,41,42,43,44
al,45,46,47,48
al,49,50,51,52
al,53,54,55,56
al,57,58,59,60
al,61,62,63,64
al,65,66,67,68
al,69,70,71,72
al,73,74,75,76
al,77,78,79,80
al,81,82,83,84
al,85,86,87,88
al,89,90,91,92
al,93,94,95,96
al,97,98,99,100
al,101,102,103,104
al,105,106,107,108
al,109,110,111,112
al,113,114,115,116
al,117,118,119,120
al,121,122,123,124
al,125,126,127,128
al,129,130,131,132
al,133,134,135,136
al,137,138,139,140
al,141,142,143,144
al,145,146,147,148
al,149,150,151,152
al,153,154,155,156
al,157,158,159,160
al,161,162,163,164
al,165,166,167,168
al,169,170,171,172
al,173,174,175,176
al,177,178,179,180
al,181,182,183,184
aoverlap,all            !冻结管与土体进行布尔运算
numcmp,area
numcmp,line
allsel
/pnum,area,1
/pnum,line,0
aplot
asel,s,area,,1,46,1     !选择要设置属性的面
aatt,2,,1
asel,s,area,,47
aatt,1,,1
lsel,s,line,,1,184,1        !选择冻结管面上的线
lesize,all,,,2                   !设置该线等分2份
lsel,s,line,,185,187,2      !选择土体边框上的线      
lesize,all,,,50
lsel,s,line,,186,188,2         
lesize,all,,,80
allsel
MSHAPE,0,2D
MSHKEY,1
!*  
FLST,5,46,5,ORDE,2  
FITEM,5,1   
FITEM,5,-46
CM,_Y,AREA  
ASEL, , , ,P51X
CM,_Y1,AREA
CHKMSH,'AREA'   
CMSEL,S,_Y  
!*  
AMESH,_Y1   
!*  
CMDELE,_Y   
CMDELE,_Y1  
CMDELE,_Y2  
MSHKEY,0
!*  
CM,_Y,AREA  
ASEL, , , ,      47
CM,_Y1,AREA
CHKMSH,'AREA'   
CMSEL,S,_Y  
!*  
AMESH,_Y1   
!*  
CMDELE,_Y   
CMDELE,_Y1  
CMDELE,_Y2  
!*  
!!!加载求解阶段
/solu
antype,trans
timint,off       !先瞬态分析
time,0.01
deltim,0.01
esel,s,mat,,1
nsle,s
d,all,temp,23     !设置土体背景值为23°
allsel
solve
/post1               
set,last            
plnsol,temp
finish

/solu                !再稳态分析
autots,on
outres,,all         
timint,on         
time,8640000         !设置终止计算时间
deltim,432000        !设置时间步长
kbc,1                !设置为阶跃加载形式
esel,s,mat,,1
nsle,s
ddelet,all,temp                 
toffst,273   
ESEL,S,MAT,,2        ! 加温度载荷为-27°
NSLE,S  
D,ALL,TEMP,-27
solve
/post1               !  后处理
set,last             !  读取最后一步结果
allsel
plnsol,temp
finish


谢谢了

双城记2

伤心了，到现在还没有一个人回复，哎。。。

iomega

Do not expect others to spend time on the tedious code without any clear description of the physical problem.

Why not just try modifying the thermal properties, boundary conditions, etc., just to verify if the model does make sense.  You will learn much more during such analysis and debug process, instead of waiting someone's help without thinking it through.

双城记2

谢谢斑竹的批评与指导
首先模拟的现象是：在土体中插入46根圆形冻结管，在冻结管中通入-27°的低温，通过该低温把周围23°的土体冻结结冰从而形成一圈0°的冻结壁。这是一个相变过程，我的模型求解后冻结效果仅仅发生在圆形冻结管周边一圈不向外扩散。
我再调试调试该模型，希望会有所变化。