Zhou Lang

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About Zhou Lang

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  1. Dear Sir or Madam, Sorry to disturb you. I am Lang. I am simulating the 1D transport of contaminant using PetrSim. I want to have the injection in the extra cell so that it could mimic the real flux boundary condition more accurately. I also set the material properties in the extra cell like water. And I was wandering if it makes sense and what the difference between this model and that inject in the cell 1 is. Thank you! Best regards, Lang
  2. Hello, everyone, When I run my TOUGHREACT model, the runlog.out file displayed "ERROR (convergence problem in initialization of water composition) Please adjust convergence criteria regarding chemical iteration and initial guess of concentration of primary species". The TOUGHREACT v2.0 manual gives: "Execution stop: yes. Self-explanatory. This error results in calling routine chdump for troubleshooting (i.e. the last chemical speciation data are output in the chdump.out file). This error occurs during the initial geochemical speciation of waters specified in chemical.inp (no minerals, before the first time step). Check the chdump.out file for clues, and also check that water temperatures specified in chemical.inp data are not too different than the initial condition of temperature specified in the flow.inp file." I am confused by the statements. I was wondering if there were something wrong in my initial water conditions (Actually, I changed the temperatures and the initial concentrations for many times based on the equilibrium constant) and how to revise it. Thank you!
  3. What anything else should I set up in this model, except for the above settings? Thank you!
  4. Hello, Everyone, I faced a problem on the surface complex. I wanted to simulate the the surface complex between the aqueous Europium+3 and solid S-sOH (a defined group) in clay. I complied the surface complex information in the database, and selected the Eu+3 and S-sOH as the primary species. Now I don't know how to set up the concentration of S-sOH in initial and boundary conditions, since it is a solid group in clay. I would appreciate if someone helps me to solve this problem. Thank you! Best regards, Lang
  5. Dear Alison, Thank you very much for your helpful reply. Best regards, Lang
  6. Hello, everyone, I am confused by the statement on Dist. This and Dist. To in PetraSim 5 User Manual. It was stated that in Page 53: "Dist. This: The distance of the connection in the extra cell. See TOUGH concepts "Spatial Discretization." Dist. To: The distance of the connection in the connecting cell." Does they meam that Dist. This is the distance between the connection interface and centroid of the extra cell; and Dist. To is the distance between the connection interface and centroid of the connecting cell ?
  7. Dear Alison, Thank you for your honest answer. It is still very helpful. Best regards, Lang
  8. Hi. I am confused by the concept of the tortuosity. I found it was defined as is the ratio of the average length of the flow paths through the medium to the straight-line length across the medium (greater than unit) in some papers; sometimes it's defined as the inverse of the above definition (less than unit); another literature defined the tortuosity coefficient as the square of the inverse of that ratio and it's sometimes defined as the diffusion coefficient of diffusing species in a porous medium, De, relative to its value in free fluid, D0. I was wondering what its definition in TOUGH/PetraSim. Thank you! Best regards, Lang
  9. Hello. I am inquiring about how to know the mechanical dispersion in the PetraSim. When I input the diffusion coefficient and tortuosity/porosity, I just can obtain the so-called effective diffusion coefficient. If we want to get the dispersion coefficient, we must know the mechanical dispersion coefficient (dispersion = effective diffusion + mechanical dispersion). Then we can apply the dispersion coefficient to the advection-dispersion equation. So how can we get the mechanical dispersion coefficient? Thank you.
  10. Dear Alison, Thank you for your reply.The problem has been solved. Thank you again. Best regards, Lang
  11. Additionally, I considered a large distribution coefficient Kd in this problem.
  12. Dear Sir or Madam, I am sorry to disturb you. I set up a very sample TOUGHREACT model, just considering the 1D advection-dispersion and adsorption problem. The flux was injected in the first cell, then the C/C0 in the first cell should be 100%. However, the value in my problem was just about 56%, instead of 100%. So I was wondering what is wrong with my model and how to fix it. Thank you! Best regards, LZ
  13. Dear Alison, Thank you very much for your prompt reply and for your helpful and constructive answer which indeed appreciate. Best regards, Lang
  14. Dear Alison, Thank you very much for your prompt reply and for your helpful and constructive answer which indeed appreciate. Best regards, Lang
  15. Dear Sir or Madam, I am Lang Zhou. I would like to set up a inclined flow model (5cm*0.0436cm*2cm), just like the picture shows. However, though layer editor to control the elevation of the cell tops, I just could make a model with 2 vertical boundaries. So I was wondering how could I get the ideal model as the first picture shows. Thank you! Best regards, Lang