小弟在做蒸汽在管内凝结换热的数值模拟,最近做不下去了,特来向各位前辈求教。管子长度为0.9m,直径为15mm,壁厚为2mm。入口为质量入口,100℃饱和蒸汽,0.00556kg/s。套管为内径30mm,外壁绝热,冷却水入口为蒸汽出口处,0.639kg/s,入口为40℃,出口为43℃。小弟在做的过程中,蒸汽在入口之后很快就完全变成水了,出口处质量流量为9.302kg/s。采用mixture模型。出口和入口处的速度一样大,整个出口截面全是水,换热系数大的出奇。小弟是新手,手上也木有金币,希望前辈能略微指点一二。udf如下:
#include "udf.h"
#include "sg_mphase.h"
#define T_SAT 373
#define LAT_HT 2.257e6
DEFINE_SOURCE(liq_src,cell,pri_th,dS,eqn)
{
Thread *mix_th,*sec_th;
real m_dot_l;
mix_th=THREAD_SUPER_THREAD(pri_th);
sec_th=THREAD_SUB_THREAD(mix_th, 1);
if(C_T(cell,mix_th)>=T_SAT)
{
m_dot_l=-0.1*C_VOF(cell,pri_th)*C_R(cell,pri_th)*
fabs(C_T(cell, mix_th) - T_SAT)/T_SAT;
dS[eqn]=-0.1*C_R(cell,pri_th)*fabs(C_T(cell,mix_th)-T_SAT)/T_SAT;
}
else
{
m_dot_l=0.1*C_VOF(cell,sec_th)*C_R(cell,sec_th)*fabs(T_SAT-C_T(cell,mix_th))/T_SAT;
dS[eqn]=0.;
}
return m_dot_l;
}
DEFINE_SOURCE(vap_src,cell,sec_th,dS,eqn)
{
Thread *mix_th,*pri_th;
real m_dot_v;
mix_th=THREAD_SUPER_THREAD(sec_th);
pri_th=THREAD_SUB_THREAD(mix_th,0);
if(C_T(cell,mix_th)>=T_SAT)
{
m_dot_v=0.1*C_VOF(cell,pri_th)*C_R(cell,pri_th)*fabs(C_T(cell,mix_th)-T_SAT)/T_SAT;
dS[eqn]=0.;
}
else
{
m_dot_v=-0.1*C_VOF(cell,sec_th)*C_R(cell,sec_th)*fabs(T_SAT-C_T(cell,mix_th))/T_SAT;
dS[eqn]=-0.1*C_R(cell,sec_th)*fabs(C_T(cell,mix_th)-T_SAT)/T_SAT;
}
return m_dot_v;
}
DEFINE_MASS_TRANSFER(lic_gas_source,cell,thread,from_index,from_species_index,to_index,to_species_index)
{
Thread *gas,*liq;
real m_lg;
gas=THREAD_SUB_THREAD(thread,from_index);
liq=THREAD_SUB_THREAD(thread,to_index);
m_lg=0.;
if(C_T(cell,liq)>=T_SAT)
m_lg=-0.1*C_VOF(cell,liq)*C_R(cell,liq)*fabs(C_T(cell,liq)-T_SAT)/T_SAT;
else
{
if(m_lg==0.)
m_lg=0.1*C_VOF(cell,gas)*C_R(cell,gas)*fabs(T_SAT-C_T(cell,gas))/T_SAT;
}
return (m_lg);
}
DEFINE_SOURCE(enrg_src,cell,mix_th,dS,eqn)
{
Thread *pri_th,*sec_th;
real m_dot;
pri_th=THREAD_SUB_THREAD(mix_th,0);
sec_th=THREAD_SUB_THREAD(mix_th,1);
if(C_T(cell,mix_th)>=T_SAT)
{
m_dot=-0.1*C_VOF(cell,pri_th)*C_R(cell, pri_th)*fabs(C_T(cell,mix_th)-T_SAT)/T_SAT;
dS[eqn]=-0.1*C_VOF(cell,pri_th)*C_R(cell,pri_th)/T_SAT;
}
else
{
m_dot=0.1*C_VOF(cell,sec_th)*C_R(cell,sec_th)*fabs(T_SAT-C_T(cell,mix_th))/T_SAT;
dS[eqn]=0.1*C_VOF(cell,sec_th)*C_R(cell,sec_th)/T_SAT;
}
return LAT_HT*m_dot;
}
![小弟在做蒸汽在管内凝结换热的数值模拟,特来向各位前辈求教。]()
换热系数.png
![小弟在做蒸汽在管内凝结换热的数值模拟,特来向各位前辈求教。-1]()
水的体积分布2.png |