Convergence problem chemistry
Hello, everyone,
I was running a water-rock interaction model with Toughreact. The runlog.out file prompted "Warning: chemistry did not converge at node A1114 (routine NEWTONEQ), Non-convergence type: relative Node temperature ....."
I adjusted the loop limit (MAXITCH) and tolerance (TOLCH) in the solute.inp file, which was of no effect.
When I run a long-term simulation, the time step size is always reduced to a value close to zero at a certain moment.
I am also wondering how to use chdump.out for debugging.
Hope someone could help me out of these problems.
Thanks!
5 replies
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I am having the same problem.
Making tolerance extremely high (1E+3) resulted in a very very small time step, and it never ends.
I am sorry for not a helpful reply, but hope somebody can explain this :(
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Usually the reasons for nonconvergence are:
1. Time step too large - set rcour to 0.5 (cfl condition).
2. Chemical system overdetermined. Look at mineral assemblages.
3. Ionic strength increasing to outside range during iteration. Try setting stimax to between 2-8.
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Hi, Eric. I just noticed your reply. I managed to get around this problem. Thanks for your help~
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Jaeshik Chung Good luck 😂