[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: kinetic problem



Dear Dr.Parkhurst,
Here is another problem we met. The problem setup is:
100 meter 1d domain with 1 meter cells
5 m/ yr flow velocity
The aquifer initially have 0.8 mol/L K-fedlspar or 2% vol. The other 98% is quartz. The aquifer has 25% porosity
No initial values, but can precipitate gibbsite, kaolinite, and muscovite (K-mica)
The phase definition is taken from example 6 of phreeqc manual.


Gibbsite
               Al(OH)3 + 3 H+ = Al+3 + 3 H2O
               log_k          8.049

       Kaolinite
               Al2Si2O5(OH)4 + 6 H+ = H2O + 2 H4SiO4 + 2 Al+3
               log_k          5.708

       K-mica
               KAl3Si3O10(OH)2 + 10 H+ = 3 Al+3 + 3 H4SiO4 + K+
               log_k          12.970

       K-feldspar
               KAlSi3O8 + 4 H2O + 4 H+ = Al+3 + 3 H4SiO4 + K+
               log_k          0.875


The incoming solution has the following compositions


SOLUTION 		0
       units      mol/kgw
	  temp	 25
	  PH         8.1
       Al         1.e-13
       K          2.74e-5
       Si         9.25e-5
	  Cl         7.62e-5
	  Na         1.509e-4
	Ca         8.843e-4
	  Mg         1.09e-4

The K-feldspar dissolution rate is 10^(-12.5) mol/sec/sq meter.

The scenario is kaolinite has slow rate (K-feldspar rate /100),
muscovite = K-feldspar rate/10000


The problem we got is: If there is no transport part in the simulation, it worked well.After adding one dimensional transport, the simulation can't converge.It warned that element Al and K has negative concentration in solution. Then it


stopped after bad RK step>500.


We attached the input files of transport and no-transport, so you can compare them.


Thank you very much.

Sincerely yours,
Hui Tan

Attachment: transport02.pqi
Description: Binary data

Attachment: Blackmesa-04-8.pqi
Description: Binary data



Project Home Page
Complete Water Resources Division Software
USGS Home Page
Water Resources Division Home Page
NRP Home Page
Help Page
USGS Privacy Statement       

Please note that some U.S. Geological Survey (USGS) information accessed through this page may be preliminary in nature and presented prior to final review and approval by the Director of the USGS. This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the sole responsibility of the user.

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. 


The URL of this page is: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/mail/msg00660.html
Email:dlpark@usgs.gov
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number 2248 since Jan 22, 1998.