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"Repeated restart of integration."
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Topic: "Repeated restart of integration." (Read 404 times)
Hosseif
Contributor
Posts: 7
"Repeated restart of integration."
«
on:
November 20, 2017, 03:57:21 PM »
I'm doing reactive transport modeling in which phreeqc has been coupled to a transport solver. I'm simulating dissolution of a mineral according to reaction A(s)=A(aq). It's a kinetic reaction and rate = kS(A-A_eq). initial solution in the domain is A=0.001 and I inject a solution with A=0.002 and dissolution happens. at some points in the simulation I'm getting an error saying ""Repeated restart of integration.""
What could be a possible reason for that?
This is part of my phreeqc input:
SOLUTION_MASTER_SPECIES
[A] [A] 1 1 1
SOLUTION_SPECIES
[A] = [A]
log_k 0
PHASES
[A]_decay
[A]=[A]
log_k 0
SOLUTION 0
units mol/kgw
[A] .002
END
SOLUTION 1
units mol/kgw
[A] .001
END
RATES
[A]_decay
-start
10 if KIN("[A]_decay")>0 then rate = ( TOT("[A]")-.001 )* 50
20 moles = rate * TIME
30 SAVE moles
-end
END
KINETICS 1
[A]_decay
-m 0.1
-cvode true
END
Best,
Hossein
«
Last Edit: November 20, 2017, 04:00:16 PM by Hosseif
»
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dlparkhurst
Top Contributor
Posts: 1210
Re: "Repeated restart of integration."
«
Reply #1 on:
November 21, 2017, 04:25:39 AM »
The sign of moles is important. The sign of moles times the coefficient in formula determines whether the concentration of [A] increases or decreases. I have rewritten your RATES equation so that [A] is removed from solution if the concentration is greater than 0.001 and removed if less than 0.001.
SOLUTION_MASTER_SPECIES
[A] [A] 1 1 1
SOLUTION_SPECIES
[A] = [A]
log_k 0
PHASES
[A]_decay
[A]=[A]
log_k 0
SOLUTION 1
units mol/kgw
[A] .002
END
RATES
[A]_decay
-start
#10 if KIN("[A]_decay")>0 then rate = ( TOT("[A]")-.001 )* 50
10 rate = ( 0.001 - TOT("[A]"))* 50
20 moles = rate * TIME
30 SAVE moles
-end
END
USE solution 1
KINETICS 1
[A]_decay
-formula [A] 1
-m 0.1
-step 1
-cvode true
END
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Hosseif
Contributor
Posts: 7
Re: "Repeated restart of integration."
«
Reply #2 on:
November 21, 2017, 10:06:05 AM »
Dear David,
Thank you so much.
I just ran the rewritten phrqc file by you. It leads to precipitation of [A]_decay phase while I'm looking for dissolution of [A]_decay phase.
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dlparkhurst
Top Contributor
Posts: 1210
Re: "Repeated restart of integration."
«
Reply #3 on:
November 21, 2017, 04:46:20 PM »
Then start with a solution with a small [A] concentration.
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"Repeated restart of integration."