5 Replies Latest reply on May 20, 2016 9:10 AM by Amit Katz

    Kitchen Gas Burner Flow Simulation

    Hamad Khaled

      Hello,

      Thanks in advance for reading my post. I am trying to perform 2d flow simulation on residential gas burner. The purpose of the simulation is to quantify the amount of CO2 captured by the exhaust fan. I am having issues with defining air as my environment. I have defined a fluid subdomain on my burner surface with combustion products CO2, water vapor and methane. I have assigned a volume flow rate out the burners’ surfaces as a boundary condition. Also, I have used an external fan on my exhaust geometry.  I will attach my model for your kind evaluation.

       

      My concerns are

      1. 1) Mass fraction of Co2 is much higher outside the exhaust hood area which is an indication of no air in the surrounding. I am not sure how to define air in the surrounding.
        1. 2)     Similarly, the temperature outside the burner area is much higher than expected. As I said earlier when I define my fluid subdomain on the burner surface, I have defined the temperature to be 500K.

      Please share with me your valuable comments to enhance my simulation and improve my results. Thanks again.

       

      Message was edited by: Hamad Khaled I have uploaded my latest file "stove emission simulation" where I tried to do 3d flow simulation on my stove burners to simulate CO2 emissions. However, I was not able to get the mesh to be 3d and I wanted to know if I can define an equation to calculate the capture efficiency of my stove fan. I have assigned the surface right above the burners to be my fan and I wanted to calculate the amount of mass of CO2 going through the fan versus the total amount emitted. is it possible to do in SW? Thanks again.

       

      Message was edited by: Hamad Khaled I have take a snapshot of the mesh attached. As you may say, the mesh does not cover the flow domain accuratley. Its more like a 2d surface mesh. Thanks a lot Mr. Katz for your continuous help.

        • Re: Kitchen Gas Burner Flow Simulation
          Amit Katz

          I made some changes to your setup. Unfortunately it's in SW2016 version, sorry if you can't open that. I'll explain what I did.

           

          First of all, you do not need fluid subdomains here. That feature is used when you have two phases of fluids (i.e. gas and liquid) that are compartmentalized and physically separated. Furthermore it needs to be applied to a volume, not a surface as in your case. This feature is used in some cases, for example in gas/liquid heat exchangers where the fluids don't physically interact.

           

          You can set your environment to be air at room temperature using the general project settings, in the initial conditions submenu, like so:

          gasmix11.PNG

          By the way, I didn't do so but I would also recommend turning on gravity in your simulation. This model relies on natural convection partially so it's an important consideration. This is also an option in the general settings under "Analysis type".

           

          Your radiating surface setup was odd looking, I wasn't sure what you were trying to do so I just disabled it. What I did instead was use the thermodynamic properties of the gas inlet to define a set temperature of 500K, like so:

          gasmix1.PNG

           

          You did not have any goals defined in this simulation. Without goals the software cannot make a good decision on when to stop the calculations. So I added some generic goals (min/max global pressure, average global temperature) and CO2 mass flow goals for your inlet and outlet.

           

          Now the results look a little more realistic.

          gasmix111.PNG

          gasmix1111.PNG

            • Re: Kitchen Gas Burner Flow Simulation
              Hamad Khaled

              Awesome!! Thanks so much Mr. Katz. Your explanation is great. I really appreciate your help. I could not open the file as you expected but I will work on implementing your recommendations.

               

              Also, I wanted your clarification if I want to have a delta "P" of the fan on the top surface do I still need to define a fan or is there a way where I can define the delta P only so that the simulation will figure out that I have lower pressure point on that surface for good representation of flow distribution.

              Thanks again for your support.

              • Re: Kitchen Gas Burner Flow Simulation
                Kim KyuHyung

                Unfortunately this problem about combustion is not supported in flow simulation. so you can't.

                as i know, the other simular tool is possible to simulate these problem such like attached image.

                combustion.jpg

              • Re: Kitchen Gas Burner Flow Simulation
                Amit Katz

                I don't understand the issue. You couldn't get the mesh to be 3D? Do you mean that you don't know how to switch to 3D flow domain?

                 

                As for your efficiency equation, you can define an equation goal. Start with two surface goals of mass flow rate of CO2, one for your inlet and one for your outlet. Then your CO2 capture efficiency equation goal is just: CO2-out/CO2-in