分享一些常用的UDF

下面分享一些简单的 udf，带领小白快速入门。

1、Lee

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#include "udf.h"
#include "sg_mphase.h"  //包含体积分数的宏
#define T_SAT 30.27   //饱和温度373.15 K
#define LAT_HT 1.e3 //汽化潜热1000 J/kg


// 液相质量源项
DEFINE_SOURCE(liq_src, cell, pri_th, dS, eqn)
{
 Thread *mix_th, *sec_th;
 real m_dot_l;// 定义相变质量kg/(m2 s)
 // mix_th存储主相的Thread指针；sec_th存储次相指针，注意ID
 mix_th = THREAD_SUPER_THREAD(pri_th); //指向混合区域的主相
 sec_th = THREAD_SUB_THREAD(mix_th, 1); //指向单相区的气相指针
 thi_th = THREAD_SUB_THREAD(mix_th, 2); //指向单相区的液相指针
 // 温度大于饱和温度，表示为蒸发
 if (C_T(cell, sec_th) >= T_SAT)
 {
   //计算蒸发量，注意液相质量流量为负值，0.1为coeff值
   m_dot_l = -0.25 * C_VOF(cell, sec_th) * C_R(cell, sec_th) * fabs(C_T(cell, sec_th) - T_SAT) / T_SAT;
   //对体积分数求导
   dS[eqn] = -0.25 * C_R(cell, sec_th) * fabs(C_T(cell, sec_th) - T_SAT) / T_SAT;
 }
 else
 {
   //计算冷凝量，液相质量分数为正值
   m_dot_l = 0.1 * C_VOF(cell, sec_th) * C_R(cell, sec_th) * fabs(T_SAT - C_T(cell, sec_th)) / T_SAT;
   //若对体积分数求导得到的值为正，干脆直接赋零值
   dS[eqn] = 0.;
 }
 return m_dot_l;
}



// 气相质量源项，解释同上
DEFINE_SOURCE(vap_src, cell, sec_th, dS, eqn)
{
 Thread *mix_th, *pri_th;
 real m_dot_v;
 mix_th = THREAD_SUPER_THREAD(pri_th); //指向混合区域的主相
 sec_th = THREAD_SUB_THREAD(mix_th, 1); //指向单相区的气相指针
 thi_th = THREAD_SUB_THREAD(mix_th, 2); //指向单相区的液相指针
 if (C_T(cell, thi_th) <= T_SAT)
 {
   m_dot_v = 0.1 * C_VOF(cell,thi_th) * C_R(cell, thi_th) * fabs(C_T(cell, thi_th) - T_SAT) / T_SAT;
   dS[eqn] = 0.;
 }
 else
 {
   m_dot_v = -0.1 * C_VOF(cell, thi_th) * C_R(cell, thi_th) * fabs(T_SAT - C_T(cell, thi_th)) / T_SAT;
   dS[eqn] = -0.1 * C_R(cell, thi_th) * fabs(C_T(cell, thi_th) - T_SAT) / T_SAT;
 }
 return m_dot_v;
}


//混合相的能量源项
DEFINE_SOURCE(enrg_src, cell, mix_th, dS, eqn)
{
 Thread *pri_th, *sec_th, *thi_th;
 real m_dot;
 pri_th = THREAD_SUB_THREAD(mix_th, 0);
 sec_th = THREAD_SUB_THREAD(mix_th, 1);
 thi_th = THREAD_SUB_THREAD(mix_th, 2);
 if (C_T(cell, mix_th) >= T_SAT)
 {
   // 得到蒸发量，Lee模型
   m_dot = -0.25 * C_VOF(cell, sec_th) * C_R(cell, sec_th) *
           fabs(C_T(cell, sec_th) - T_SAT) / T_SAT;
   //对温度求导，若为负则保留，否则赋值零
   dS[eqn] = -0.1 * C_VOF(cell, sec_th) * C_R(cell, sec_th) / T_SAT;
 }
 else
 {
   //得到冷凝量
   m_dot = 0.1 * C_VOF(cell, thi_th) * C_R(cell, thi_th) *
           fabs(T_SAT - C_T(cell, thi_th)) / T_SAT;
   dS[eqn] = -0.1 * C_VOF(cell, thi_th) * C_R(cell, thi_th) / T_SAT;
 }

 // 返回热量值，利用潜热与质量流量的乘积得到
 return LAT_HT * m_dot;
}

2、ke 模型

2.1 ke1

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#include "udf.h"

#define Cu 0.09
#define Us 2.2
#define zs 10
#define a 0.15
#define ZG 350

DEFINE_PROFILE(k_profile,t,i)
{
	real z,x[ND_ND],Uz,Iz;
	face_t f;

	begin_f_loop(f,t)
	{
		F_CENTROID(x,f,t);
		z = x[2];
		Uz = Us*pow(z/zs,a);
		Iz = 0.1*pow(z/ZG,-a-0.05);

		F_PROFILE(f,t,i) = pow(Iz*Uz,2);
	}
	end_f_loop(f,thread)
}

DEFINE_PROFILE(e_profile,t,i)
{
	real z,x[ND_ND],Uz,Iz,kz;
	face_t f;

	begin_f_loop(f,t)
	{
		F_CENTROID(x,f,t);
		z = x[2];
		Uz = Us*pow(z/zs,a);
		Iz = 0.1*pow(z/ZG,-a-0.05);
		kz = pow(Iz*Uz,2);

		F_PROFILE(f,t,i) = pow(Cu,0.5)*kz*Us/zs*a*pow(z/zs,a-1);
	}
	end_f_loop(f,thread)
}

2.2 ke2

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#include "udf.h"

#define Cu 0.09
#define Us 2.2
#define zs 10
#define a 0.10
#define ZG 250

DEFINE_PROFILE(k_profile,t,i)
{
	real z,x[ND_ND],Uz,Iz;
	face_t f;

	begin_f_loop(f,t)
	{
		F_CENTROID(x,f,t);
		z = x[2];
		Uz = Us*pow(z/zs,a);
		if(z<5)
			Iz = 0.18;
		else
			Iz = 0.1*pow(z/ZG,-a-0.05);
		F_PROFILE(f,t,i) = 1.5*pow(Uz*Iz,2);
	}
	end_f_loop(f,thread)
}

DEFINE_PROFILE(e_profile,t,i)
{
	real z,x[ND_ND],Uz,Iz,kz,lz;
	face_t f;

	begin_f_loop(f,t)
	{
		F_CENTROID(x,f,t);
		z = x[2];
		Uz = Us*pow(z/zs,a);
		if(z<5)
			Iz = 0.18;
		else
			Iz = 0.1*pow(z/ZG,-a-0.05);
		kz = 1.5*pow(Uz*Iz,2);
		F_PROFILE(f,t,i) = F_PROFILE(f,t,i) = pow(Cu,0.5)*kz*Us/zs*a*pow(z/zs,a-1);
	}
	end_f_loop(f,thread)
}

3、质量入口

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#include "udf.h"
DEFINE_PROFILE(inlet_mlih2,thread,i)
{
	face_t f;
	real flow_time = CURRENT_TIME;
	begin_f_loop(f,thread)
	{
		if(flow_time <= 38)
			F_PROFILE(f,thread,i) = 4.76*0.75;
		else
			F_PROFILE(f,thread,i) = 0;
	}
	end_f_loop(f,thread)
}
DEFINE_PROFILE(inlet_mh2,thread,i)
{
	face_t f;
	real flow_time = CURRENT_TIME;
	begin_f_loop(f,thread)
	{
		if(flow_time <= 38)
			F_PROFILE(f,thread,i) = 4.76*0.25;
		else
			F_PROFILE(f,thread,i) = 0;
	}
	end_f_loop(f,thread)
}

4、速度入口

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#include "udf.h"
DEFINE_PROFILE(inlet_x,thread,index)
{
	real y,v0,h0;
	real x[ND_ND];
	face_t f;
	v0=2.2;
	h0=10;
	begin_f_loop(f,thread)
	{
		F_CENTROID(x,f,thread);
		y=x[2];
		F_PROFILE(f,thread,index) = v0*pow(y/h0,0.10);
	}
	end_f_loop(f,thread)

}

5、时间步长

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#include "udf.h"

DEFINE_DELTAT(mydeltat,domain)
{
    real time_step;
    real flow_time = CURRENT_TIME;
    if(flow_time<120)
        time_step = 1;
    else
        time_step = 0.0005;
    return time_step;
}
模拟 > Fluent
#UDF #Fluent #模拟
分享一些常用的UDF
http://example.com/2024/03/17/010 常用的udf/
作者
DB
发布于
2024年3月17日
许可协议