[tante]

Hi

I am a newbie in CFD, using COMSOL.

I am now modelling low temperature combustion of methane in air (2% methane). I thought 2% is not incomparable to 20% oxygen in gas mixture so I use transport of concentrated species module. However, there is always a 'division by zero' problem. I have checked the error message and found the equation. There are only 2 denominators in the equation: tcs.T and tcs.Mn(molar mass of mixture), as follows:

Segregated Step 3
Division by zero.
- Function: /
Failed to evaluate expression.
- Expression: dvol_spatial*(((comp1.tcs.DT_wCH4*(((comp1.tcs.nx* mean(d(comp1.tcs.T,x)))+(comp1.tcs.ny*mean(d(comp1 .tcs.T,y))))+(comp1.tcs.nz*mean(d(comp1.tcs.T,z))) ))/comp1.tcs.T)+((((comp1.wCH4*comp1.tcs.rho)*comp1.t cs.Dm_wCH4)*(((comp1.tcs.nx*mean(d(comp1.tcs.Mn,x) ))+(comp1.tcs.ny*mean(d(comp1.tcs.Mn,y))))+(comp1. tcs.nz*mean(d(comp1.tcs.Mn,z)))))/comp1.tcs.Mn))

I really don't know what to do with this. Any tips?

[steve lee]

I have short experience to use COMSOL.. So I can't help you but!
I recommand this page.

https://www.comsol.com/community/