[求助]加载热流密度后，求解显示温度没有变化？各位大侠看看
就是在两层的夹层处加热流密度，结果模型显示为红色，没有任何结果。我的命令流如下：hflux=15.27
/prep7
keyw,pr_therm,1
blc4,,,1,0.08
blc4,,,1,-0.45
nummrg,all
mp,ex,1,160000
mp,prxy,1,0.22
mp,kxx,1,0.157
mp,dens,1,2.4e-3
mp,c,1,700
mp,ex,2,63000
mp,prxy,2,0.2
mp,kxx,2,1.13
mp,dens,2,2.23e-3
mp,c,2,800
et,1,plane55
KEYOPT,1,3,1
lesize,1,,,40
lesize,1,,,20
lesize,1,,,40
lesize,2,,,4
lesize,6,,,20
mshkey,1
mat,1
amesh,1
mat,2
amesh,2
finish
/SOL
nsel,s,,,1
nsel,s,,,3
nsel,s,,,4
sf,all,HFLUX,hflux
allsel
ANTYPE,4
NSUBST,50,100,20
AUTOTS,1
KBC,0
LNSRCH,1
TIME,1000
solve
Re:[求助]加载热流密度后，求解显示温度没有变化？各位大侠看看
是不是热流密度的加载方法有误啊？Re:[求助]加载热流密度后，求解显示温度没有变化？各位大侠看看
Just several advices on your model and how to know if the analysis is correct or not quickly:1. Thermal property values are not correct.
>mp,dens,2,2.23e-3
>mp,c,2,800
The heat capacity based on your number is Cp = 2.23e-3*800= 1.784J/m^3-K
NO material in the world has such heat capacity value. Combined with the k = 1.13 W/m-K, you ended up with a material of thermal diffusivity alf beyond the best heat conductor in the world... alf = k/Cp
typical c*dens should be order of 10^6 J/m^3-K
2. you only have heat put in, but no boundary conditions to let heat dissipate out -> temperature keep increase forever.
3. your dimension is order of L=1m -> thermal diffusion time = L^2/alf ~ 1s for your problem, which means in seveal seconds your temperature distribution will be unifrom everywhere in the domain. While your calculation time is ~1000s.
Re:[求助]加载热流密度后，求解显示温度没有变化？各位大侠看看
谢谢，iomega给予的帮助由于我的疏忽，我没有说明我用的单位制是mm，g，ms，所以我定义的材料属性是没有问题的
按照你的提示，我施加了对流的边界条件，但还是显示温度没有变化
求解的时间也按照你所给的公式设为了600ms
修改后的命令流如下：
hflux=15.27
/prep7
keyw,pr_therm,1
blc4,,,1,0.08
blc4,,,1,-0.45
nummrg,all
mp,ex,1,160000
mp,prxy,1,0.22
mp,kxx,1,0.157
mp,dens,1,2.4e-3
mp,c,1,700
mp,ex,2,63000
mp,prxy,2,0.2
mp,kxx,2,1.13
mp,dens,2,2.23e-3
mp,c,2,800
et,1,plane55
KEYOPT,1,3,1
lesize,1,,,40
lesize,2,,,4
lesize,6,,,20
mshkey,1
mat,1
amesh,1
mat,2
amesh,2
finish
/SOL
ANTYPE,trans
timint,on
time,600
deltim,10,2,200
autots,on
outres,,all
nsel,s,,,1
nsel,s,,,3
nsel,s,,,4
sf,all,HFLUX,hflux ！夹层处加热流密度
allsel
lsel,s,,,4
lsel,s,,,8
lsel,s,,,2
lsel,s,,,6
nsll,s,1
sf,all,conv,12.5e-6,20！两边加对流载荷
allsel
tunif,20
solve
结果还是有问题，希望大侠在给予指点，谢谢了
Re:[求助]加载热流密度后，求解显示温度没有变化？各位大侠看看
温度梯度显示也有问题Re:[求助]加载热流密度后，求解显示温度没有变化？各位大侠看看
Why use the non-standard units for calculation. Remember you also have to consider the unit change for Watt because it is J/s and J = F*m...What's the unit of your heat flux? it maybe be so small.
suggest you to use m s and kg to draw the dimension - it's easy for you to debug...
>nsll,s,1
>sf,all,conv,12.5e-6,20 ！两边加对流载荷
you type wrong, should be nsel... xuexi le hendujo le
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