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Clarifications on Site Species and Porous Zone Material

    • sudeepns.197me025
      Subscriber

      Dear Ansys Community, 

      Greetings! 


      I am trying to develop a surface reaction for steam methane reforming reaction. 
      For this purpose, I am using customised NICKEL material as a POROUS catalyst. 
      Hence, I defined the properties of the porous catalyst (density, thermal conductivity, Cp, Molecular Weight) and added it to a create/edit materials > species > mixture. I have attached an image for your reference. 

      However, while trying to import that Nickel site species in the porous zone, it does not appear in the drop-down list. (Attached image for your reference)


      Now, I have the following doubts. 
      1. Is there any possible way to define the site species in the drop-down list under the porous section?
      or
      2. If I define the 'NICKEL' element and give the same properties as Nickel site species, do the tools consider both as the same or will they both be different?
      If they are both different, how can we solve this problem?

      Looking forward to clarifications. 





       

       

       

       

    • Rob
      Forum Moderator

      The value you're highlighting is for thermal conduction in the solid part of the porous media. Have a look in the Reactions tab. 

    • sudeepns.197me025
      Subscriber

      Dear Sir, Thank you for the reply. 

      Yes, Exactly. 
      I have defined the thermal conductivity values for Ni_Site in the reaction tab (Ni_Site is a catalyst, and gas will flow inside the porous catalyst), and Ni_Site has to be used as a solid material in the porous zone. How can it be achieved?

    • Rob
      Forum Moderator

      Then you need to add a Nickel solid material too. If you have Ni_site as the reactive species then Ni_solid may be a good option. Note, don't use the chemical formula (Ni) for both as that can mess with some of the TUI commands.

    • sudeepns.197me025
      Subscriber

      Dear Sir, Thank you for the suggestion. 

      I have even tried creating the Ni_Solid in the reaction. Even though Ni_Solid doesn't appear in the 'solid material name' drop-down list under the porous zone section. 

      I would request you to give me a suitable reference or any source to achieve the same. 

    • Rob
      Forum Moderator

      The porous material is a solid type. The surface reaction material may need to be fluid type? 

    • sudeepns.197me025
      Subscriber

      Yes sir. 

      I have defined catalyst zone as fluid. This will make me to define poroisty easily.
      Further, The solid material in the porous zone should act as site species. This is where exactly I am finding difficulty. 

    • Rob
      Forum Moderator

      No, the solid species is for the media conductivity. The fluid species may well be for the site species.

    • sudeepns.197me025
      Subscriber

      Thank you, sir, for the clarification. 

      So, defining the site species (Nickel-Site) in the reaction tab for surface reaction and further, defining the porosity of 0.3 and selecting the Nickel in the drop-down list by giving the same property as the Nickel site would have no issues in the solution (surface reaction). Isn't it, sir?

    • Rob
      Forum Moderator

      Correct - it's two separate parts of the calculation. 

    • sudeepns.197me025
      Subscriber

      Thank you very much for the clarification, sir. 

      Further, if you have any tutorial files or documents related to surface reaction in the porous zone, I am requesting you to share the files, sir. 

    • Rob
      Forum Moderator

      I can only point you at the public documentation and examples as the Forum bypasses the Export Checks that commercial users undergo. Please check Help (from the solver) and Learning (here). 

    • sudeepns.197me025
      Subscriber

      Good Morning Sir, 
      Thank you for the reply. 

      As per your suggestions, I created Ni_Site in the Create/Edit Section under materials for surface reaction and chose Ni in the Porous zone drop-down list by giving the same property as Ni_Site to the Nickel in the porous zone. 

      However, I come across the following difficulties. 
      1. I was not able to choose the 'Non-equilibrium' in the porous zone. It was greyed. Hence, I was not able to enter the interfacial area density and Convective heat transfer values. 
      2. However, I continued with Equilibrium conditions in a porous zone, and I first used the volumetric reaction and then the surface reaction. Whenever I use the surface reaction condition, '#f1 error' gets displayed on the screen, and fluent exits automatically. 

      Looking forward to your suggestions to get rid of this problem.  

      thank you. 

    • Rob
      Forum Moderator

      Check model compatability for the first point. For the second, is there anything written in the transcript (.trn file)?

    • sudeepns.197me025
      Subscriber

      Dear Sir, Greetings

       

      I looked into the .trn fike, but could not understand it better. 

      Here are the important screenshots of the .trn file and looking forward your help to solve this issue. 

      The reaction happens perfectly till the volumetric and as soon as I switch on the surface reaction, I get the error. 


       

       

       

    • Rob
      Forum Moderator

      Why have you got nitrogen in your mixture if there isn't any in the domain? 

      SIGSEV often means there's some data missing somewhere, so my guess would be the surface reaction isn't set up right. Given you're using a GUI journal (a really bad idea, always use TUI journals) I'd double check you're actually adding all data into the model. 

    • sudeepns.197me025
      Subscriber

      Thank you for the continuous support and time, sir. 

      1. I have read in the manual that the last species in the list should be a dummy species because, in fluent, under the create and edit material section, the last species is not considered for the Boundary conditions. I have attached the screenshots for example. Capture 1 contains O2 as the last species, and it is not visible in Boundary conditions to select. So I have chosen CH4, CO2, CO, H2 and H2O, which will be available in BC and N2, being the last species, will not be available. 

        2. For Surface reaction, I have written the UDF, and it's getting imported correctly without any error. I am using an inbuilt compiler (Ansys version: 2024 R1). 
        I am giving reactions under the mixture section. Attached is a screenshot for your kind perusal and there it self I am mentioning the site density of Ni_Site. Please let me know, where I am going wrong. 

        3. Is there any way to get to know, which data I have missed for surface reaction (From Output files?)

        4. can you brief me on the procedure for using TUI journals?

        Looking forward to your reply.

       

       

       

       

    • Rob
      Forum Moderator

      No, the last species should be the largest component, and is what ever isn't the others. So don't use a dummy species. For an air combustion model I'd have nitrogen last as it's likely around 70-80% by volume of the mixture. 

      What part does the wall species play in the reaction? If you're using a UDF check all materials/species are available and correctly defined in the UDF. 

      TUI journals use the commands in the Console. If you click into Console and press you'll see a list of commands. Type the command and press to trigger, and again to see the new list. So,

      /display/object.... etc

      will display an object (contour or whatever). Use q (lower case Q) to move up a level in the menu tree.  GUI journals rely on panels being open/closed correctly and identically each time and "Button-1" is found on each panel, so is not unique to a panel which can cause interesting things to happen. 

    • sudeepns.197me025
      Subscriber

      Sir, Thank you for the suggestions. 

      I am selecting H2- Air Mixture in the species transport, and the list doesn't contain CH4, CO2, and CO. 

      After completing this process, I remove the air, and O2 from the default list. Thereafter, in the boundary conditions, the last species is not visible. 

      Further I have attached the basic image as a reference for you about my volumetric and surface reaction area. The surface reaction happens inside the porous catalyst. 

       

      I am looking forward to your reply, sir. 

      The species used in the UDF is in line with the species selected for the reaction. I have cross-verified it. 

      Sir, It would be highly appreciable if you could please provide me with the tutorial file to carry out the surface reaction in the porous zone. 

    • Rob
      Forum Moderator

      I'm not aware of any tutorials covering this. Have you set the options in the Reaction tab of the fluid zone?

    • sudeepns.197me025
      Subscriber

      Yes Sir, Total 6 reactions. 
      3 Volumetric reactions and 3 surface reactions. 

    • Rob
      Forum Moderator

      Here?

       

    • sudeepns.197me025
      Subscriber

      Dear Sir, Thank you for the reply. 

      I have attached the screenshot, where I will be defining the three volumetric and three surface reactions. 

       

      Looking forward for your valuable suggestions. 

       

    • Rob
      Forum Moderator

      That's the Species>Reactions panel, look closely at what I screen grabbed. 

    • sudeepns.197me025
      Subscriber

      Dear Sir, Greetings.

      Yes, in the screen shared by you, I use, surface to volume ratio as 300 (Based on my calculations) and reaction mechanism I chose is surface reaction in the drop down list. 

       

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