# how the EulerImplicit chemistry solver solves the concentration?

 Register Blogs Members List Search Today's Posts Mark Forums Read October 4, 2019, 04:06 how the EulerImplicit chemistry solver solves the concentration? #1 New Member   Join Date: May 2013 Posts: 22 Rep Power: 8 Hi, all here! These days I used the EulerImplicit chemistry solver to solve the reactions in the flow filed. But I found that the concentration solved by the solver behaved strange in my case, so I traced into the EulerImplicit chemistry solver source to learn how it solves the concentration. in the EulerImplicit.C file, there are lines to construct the matrix: Code: ``` for (label i=0; i& R = this->reactions_[index]; forAll(R.lhs(), s) { const label si = R.lhs()[s].index; const scalar sl = R.lhs()[s].stoichCoeff; RR[si][rRef] -= sl*pr*corr; RR[si][lRef] += sl*pf*corr; } forAll(R.rhs(), s) { const label si = R.rhs()[s].index; const scalar sr = R.rhs()[s].stoichCoeff; RR[si][lRef] -= sr*pf*corr; RR[si][rRef] += sr*pr*corr; }``` let's consider the concentration of a species, c, the new concentration after the time step will be c', then the equation for the code above can be written as: ( RR + 1/dt ) * c'= c/dt here the ( RR + 1/dt ) comes from the code (1), and RR is the reaction rate which have the unit of kmoles/m^3/s rearrange the equation, I got RR * c' = ( c - c' ) / dt = dc/dt so, here is my question, why on the left the " RR * c' " appear? shouldn't it be RR = ( c - c' ) / dt = dc/dt the right equation? the " RR * c' " has the unit of kmoles/m^3/s * kmoles/m^3, which is different of dc/dt that has the unit of kmoles/m^3/s... does anyone has the reference of the EulerImplicit chemistry solver that used in the OF? please help me. Thank you!  Thread Tools Search this Thread Show Printable Version Email this Page Search this Thread: Advanced Search Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode 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 OffTrackbacks are Off Pingbacks are On Refbacks are On Forum Rules Similar Threads Thread Thread Starter Forum Replies Last Post wlt_1985 FLUENT 11 October 12, 2018 09:23 sachinlb OpenFOAM Community Contributions 22 July 28, 2017 06:26 perry OpenFOAM Running, Solving & CFD 4 May 26, 2014 09:09 Roued CFX 1 October 2, 2001 17:49 tokai CFX 10 July 17, 2001 17:25