CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

evaporation in vof

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 25, 2006, 05:29
Default evaporation in vof
  #1
asghari
Guest
 
Posts: n/a
Hi all, how to involve evaporation process in vof by udf's? can everybody give me an example(with respective udf) in this case? thank all.

  Reply With Quote

Old   May 25, 2006, 22:11
Default Re: evaporation in vof
  #2
cg
Guest
 
Posts: n/a
Here's a UDF to propagate the VOF interface at a specified speed. I think that you can modify this accordingly for evaporation...

#include "udf.h" #include "sg.h" #include "sg_mphase.h" #include "flow.h" #include "mem.h"

/************************************************** ************/ /* UDF for specifying an interfacial area density */ /************************************************** ************/

#define flame_speed 2.;

DEFINE_ADJUST(area_density, domain) { Thread *t; Thread **pt; cell_t c; Domain *pDomain = DOMAIN_SUB_DOMAIN(domain,P_PHASE); real voidx, voidy, voidz=0;

Alloc_Storage_Vars(pDomain,SV_VOF_RG,SV_VOF_G,SV_N ULL); Scalar_Reconstruction(pDomain, SV_VOF,-1,SV_VOF_RG,NULL); Scalar_Derivatives(pDomain,SV_VOF,-1,SV_VOF_G,SV_VOF_RG,Vof_Deriv_Accumulate);

mp_thread_loop_c (t,domain,pt)

if (FLUID_THREAD_P(t))

{

Thread *tp = pt[P_PHASE];

begin_c_loop (c,t)

{

voidx = C_VOF_G(c,tp)[0];

voidy = C_VOF_G(c,tp)[1]; #if RP_3D

voidz = C_VOF_G(c,tp)[2]; #endif

/* calculation of the interfacial area density */

C_UDMI(c,t,0)= sqrt( SQR(voidx) + SQR(voidy) + SQR(voidz) );

}

end_c_loop (c,t)

}

Free_Storage_Vars(pDomain,SV_VOF_RG,SV_VOF_G,SV_NU LL); }

DEFINE_SOURCE(reactants, cell, thread, dS, eqn) { real source; Thread *tm = THREAD_SUPER_THREAD(thread); Thread **pt = THREAD_SUB_THREADS(tm); source = - C_UDMI(cell, tm, 0)*C_R(cell,pt[0]); source *= flame_speed; dS[eqn] = 0; return source; }

DEFINE_SOURCE(product, cell, thread, dS, eqn) { real source; Thread *tm = THREAD_SUPER_THREAD(thread); Thread **pt = THREAD_SUB_THREADS(tm); source = C_UDMI(cell, tm, 0)*C_R(cell,pt[0]); source *= flame_speed; dS[eqn] = 0; return source; }

  Reply With Quote

Old   May 26, 2006, 12:03
Default Re: evaporation in vof
  #3
greg
Guest
 
Posts: n/a
meby this will help you. By the way do you know haw to add a :from_species_index and to_species_index? the is only from_phase_index and to_phase_index. I don`t know how to do it.

/* UDF to define a simple mass transfer based on Saturation

Temperature. The "from" phase is the gas and the "to" phase is the

liquid phase */

#include "udf.h"

DEFINE_MASS_TRANSFER(liq_gas_source,cell,thread,fr om_index,from_species_index, to_index, to_species_index) {

real m_lg;

real T_SAT = 373.15;

Thread *gas = THREAD_SUB_THREAD(thread, from_index);

Thread *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;

}

if ((m_lg == 0. ) && (C_T(cell, gas) <= T_SAT))

{

m_lg = 0.1*C_VOF(cell,gas)*C_R(cell,gas)*

fabs(T_SAT-C_T(cell,gas))/T_SAT;

}

return (m_lg); }
  Reply With Quote

Old   May 27, 2006, 03:58
Default Re: evaporation in vof
  #4
asghari
Guest
 
Posts: n/a
thank you , But is this UDF included heat transfer process and may be included this process?
  Reply With Quote

Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
VOF simulate interface motion during evaporation ellen peng FLUENT 1 February 11, 2021 07:58
evaporation using VOF in STAR CCM+ aaron_lan STAR-CCM+ 2 July 27, 2018 11:26
about VOF and evaporation mengyue1 FLUENT 5 April 7, 2015 20:08
Question:Considerations about the evaporation in VOF dokeun FLUENT 10 February 24, 2011 21:47
evaporation and condensation in the VOF model Glev FLUENT 0 December 24, 2004 05:55


All times are GMT -4. The time now is 05:28.