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.

heat and mass transfer

Please login with a confirmed email address before reporting spam

Hi, I'm trying to simulate the methane combustion in a tubular reactor. For this i try to couple laminar flow, heat transfer in fluids and transport of concentrated species. I follow the round jet burner tutorial, because is very similar, only has a different feature, in my study case the reaction kinetics is necessary. I do a first study where the reacting flow is solved, and in a second study, with two steps, i solve in the first step the heat transfer using the solution of study 1 and in the second step i solve the fully coupled model.

Well, the first study is solved correctly, i can use whatever temperature in the Transport Propierties (i faced the negative concentrations using max(eps^2,r)).

Howerer when i tried to solve the second study and use ht temperature as input in Transport Propierties I get the following errors: Step 1: if I use an inlet temperatura lower than 750K (aprox.) its ok (from that temperature the activation energy is reached and reaction occurs). In other case, I have this error: "The dependent variables comp1.p, comp1.sof.inl1.Pinl, comp1.u, comp1.w are missing in the segregated solver steps. Add them to existing or new steps"

Step 2: "undefinde value found in the equation residual vector"

I attach my model, in case someone would have time to take a look. Thanks in advance



0 Replies Last Post 23 gen 2018, 07:36 GMT-5
COMSOL Moderator

Hello Francisco Palomo

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.

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.