Menu

Discussion Forum

New Discussion
Filter

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Reg: Question in evaporation of droplet simulation

Posted Apr 13, 2010, 1:56 a.m. EDT 4 Replies

Sakthish Sathasivam
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi,

I just want to simulate the momentum and heat transfer between a droplet in a moving air stream. I have used the(Multi-phase) k-epslon turbulent model for momentum transfport and Convection adn conduction heat transfer model extended with turbulent heat transfer. I have 2 problems,( THe droplet is modelled as a circle in 2D with axial symmetry)

I am not sure how to specify/calculate the turbulent thermal conductivity

After i run the model with zero turbulent thermal conductivity, there seems to be no heat transfer between the droplet and air stream.

Could someone please help with this.

Thanks,


Sakthish

4 Replies Last Post Jul 16, 2014, 7:35 p.m. EDT
Naveed Akhtar
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Apr 13, 2010, 3:20 a.m. EDT
Hi

This is a two-phase problem. Are you using the right module for heat transfer and momentum equation required for two-phase flow? As far as I know, there are level-set and phase field modules for multiphase flow but nothing for multiphase heat transfer- are you using one of these? Could you be in more detail about your model?

Regards
Naveed
Hi This is a two-phase problem. Are you using the right module for heat transfer and momentum equation required for two-phase flow? As far as I know, there are level-set and phase field modules for multiphase flow but nothing for multiphase heat transfer- are you using one of these? Could you be in more detail about your model? Regards Naveed
Sakthish Sathasivam
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Apr 13, 2010, 11:54 a.m. EDT
Hi,

Thanks for the reply. Yes i have used the two phase flow with level set method. And your right i could not find any heat transfer model that seperately deals with two phase, but i used the " Conduction & Convection" with turbulence enabled. I am guessing this should be sufficient enough and cover the heat transfer that takes place in the flow.

Sakthish
Hi, Thanks for the reply. Yes i have used the two phase flow with level set method. And your right i could not find any heat transfer model that seperately deals with two phase, but i used the " Conduction & Convection" with turbulence enabled. I am guessing this should be sufficient enough and cover the heat transfer that takes place in the flow. Sakthish
Navid Asadiznajani
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Apr 28, 2011, 2:17 p.m. EDT
Hi Sakthish

I have a same problem. using level set method (although i am still in trouble with level set) I was wonder how we can add heat transfer analysis to it?

so are you saying if we do a laminar two phase flow, level set and want to know the temperature or (heat radiation in my case) is not doable :(

I was thinking I can add physic 'heat transfer with surface to surface radiation" physic to it and do simulation with them. do you think it is doable?

like the hot fluid flows in a canal then the boundary of the canal gets heated by that as the hot fluid flows and conducts and radiates heat.

how is it doable? is it.

Thanks in advance
Hi Sakthish I have a same problem. using level set method (although i am still in trouble with level set) I was wonder how we can add heat transfer analysis to it? so are you saying if we do a laminar two phase flow, level set and want to know the temperature or (heat radiation in my case) is not doable :( I was thinking I can add physic 'heat transfer with surface to surface radiation" physic to it and do simulation with them. do you think it is doable? like the hot fluid flows in a canal then the boundary of the canal gets heated by that as the hot fluid flows and conducts and radiates heat. how is it doable? is it. Thanks in advance
Mohammad Amin Kazemi
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jul 16, 2014, 7:35 p.m. EDT

Hi,

Thanks for the reply. Yes i have used the two phase flow with level set method. And your right i could not find any heat transfer model that seperately deals with two phase, but i used the " Conduction & Convection" with turbulence enabled. I am guessing this should be sufficient enough and cover the heat transfer that takes place in the flow.

Sakthish


Please note that in level set and phase field method, you are not dealing with two fluids anymore. What you have is just one fluid with physical properties varying with level set/phase field parameter.
Something like k=k1*phi+k2*(1-phi)
So, what you need to do is to define each parameter as a function of phi. Then choose a heat transfer physics and solve the problem.
I hope this is helpful.
[QUOTE] Hi, Thanks for the reply. Yes i have used the two phase flow with level set method. And your right i could not find any heat transfer model that seperately deals with two phase, but i used the " Conduction & Convection" with turbulence enabled. I am guessing this should be sufficient enough and cover the heat transfer that takes place in the flow. Sakthish [/QUOTE] Please note that in level set and phase field method, you are not dealing with two fluids anymore. What you have is just one fluid with physical properties varying with level set/phase field parameter. Something like k=k1*phi+k2*(1-phi) So, what you need to do is to define each parameter as a function of phi. Then choose a heat transfer physics and solve the problem. I hope this is helpful.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content