Learning Forum

[ngothientu]

Hello every one,nI would like to simulate the behavior of carbon particles in a mixture of air and carbon particle (carbon diameter of 2.5 micrometers) under 2 different constant temperatures. nMy required input is carbon diameter, volume fractions of carbon in the mixture (it can set in the Patch after Initialize Click), Mass Diffusivity, and Thermal Diffusion Coefficient.nMy problem is that when I only choose the Mixture model in Ansys, I'm able to enter carbon diameter, volume fractions of carbon. But I can not enter the Mass Diffusivity and Thermal Diffusion Coefficient in the mixture material. Otherwise, when I only choose the Species Transport, I'm able to enter the Mass Diffusivity, and Thermal Diffusion Coefficient but can not enter carbon diameter (in Phase Define) and volume fractions of carbon.nSo, I think I need to combine the Species Transport model and Mixture model but when I change the Mass Diffusivity, and Thermal Diffusion Coefficient, the results for air fraction and carbon fraction distribution contour are NOT CHANGE.nWhat is my wrong procedure.??? Please anyone help me. I really appreciate it. Thank you in advance.n

[DrAmine]

Duplicate? Mixture Model with Slip and you can provide diameter.n

[ngothientu]

Thank you, Dr. Amine for the quick response. But If I need to consider the range of Mass Diffusivity or Thermal Diffusion Coefficient and also input the carbon diameter. So what model should I need to setup??? nThank you so much.n

[ngothientu]

Duplicate? Mixture Model with Slip and you can provide diameter.https://forum.ansys.com/discussion/comment/106094#Comment_106094

Thank you, Dr. Amine for the quick response. But If I need to consider the range of Mass Diffusivity or Thermal Diffusion Coefficient and also input the carbon diameter. So what model should I need to select to model???nThank you so much.n

[Rob]

If you have a multiphase system the second phase (carbon) cannot diffuse within the carrier fluid. If the carbon is modelled as a species then it's a molecular mixture so there is no diameter.nLooking at the effect of temperature. In reality that will cause buoyancy driven flow in the carrier fluid. If you've not switched to a temperature dependent density and don't have a temperature gradient nothing will happen.nHave a very careful read through the Fluent manual covering species (non reacting flow) and multiphase modelling. The courses listed at the very top of the page may also be of use. Then you'll understand what is being assumed in the models to repose the question and simulation settings.n

[ngothientu]

If you have a multiphase system the second phase (carbon) cannot diffuse within the carrier fluid. If the carbon is modelled as a species then it's a molecular mixture so there is no diameter.Looking at the effect of temperature. In reality that will cause buoyancy driven flow in the carrier fluid. If you've not switched to a temperature dependent density and don't have a temperature gradient nothing will happen.Have a very careful read through the Fluent manual covering species (non reacting flow) and multiphase modelling. The courses listed at the very top of the page may also be of use. Then you'll understand what is being assumed in the models to repose the question and simulation settings.https://forum.ansys.com/discussion/comment/106112#Comment_106112

Thank you Sir. Rob. Your comment is helpful to me. Thank you so much.n

[DrAmine]

Molecular Mixing: Species ModelnMacroscopic Mixing /Segregation: Multiphase Modeln

[ngothientu]

Molecular Mixing: Species ModelMacroscopic Mixing /Segregation: Multiphase Modelhttps://forum.ansys.com/discussion/comment/106131#Comment_106131

Thank you, Dr. Amine. That is good information for me. Thank you so much. Arrayn