I want to simulate particulate matter concentration inside an office room.The particles are coming along with the air through window and it is going out through the ventilation. The concentration of particulate matter in air is 200 mic grm/m3 .The density of particle is 850 kg/m3. I am using k-epsilon model for turbulence but not able to do the particle concentration analysis inside the room. Could anyone please tell me which model and how I can do the concentration analysis in Ansys Fluent?
Have an idea from here..
http://www.ce.utexas.edu/prof/Novoselac/classes/ARE372/Handouts/Tutorial_example.pdf
Dear Mithresh,
You may have two approaches to model the particle concentration in the office. The first one is Eulerian-Eulerian approach, i.e., modeling the particle concentration as a continuous phase in the air in Eulerian scheme. For your case, I think the drift flux model may work better. The other one is Eulerian-Lagrangian approach, which treats the particles as discrete phase and traces the particle tracks in Lagrangian scheme. I attached some of my previous articles discussing these problems for your references.
Good luck.
Article Particle dispersion and deposition in ventilated rooms: Test...
Article Modeling of ultrafine particle dispersion in indoor environm...
Article Comparison of indoor aerosol particle concentration and depo...
In addition to solving the general transport equation available in fluent, you need to define an additional user defined scalar transport equation for the transport of concentration. You have to model that equation as per your requirement. Mesh the whole room as your flow domain and define required boundary conditions for the user defined scalar at the inlet (window).
I think, you need to define uds0=1 at the inlet (window of the room ).
Find more details about UDS modeling from the fluent manuals.
Hi Mithresh
I would like to know what is the size of PM you are talking about and what is the density of that PM you have considered?
As you discussed I also do the same but in outdoor condition. Upto my understanding of FLUENT, you can choose either your PM as solid phase or gaseous phase of your choice. I have inferred from many studies that particles less than 20 microns are considered as gaseous phase in dispersion modeling becauz of its low settling velocity.
But if you are interested with particle trajectories, then you have only choice as solid phase. Then your model must be a multi-phase analysis with Eulerian-Lagrangian approach and you have to concentrate on injection points.
Thank you Prof.Bin Zhao. I think your suggestion can help me resolve my problem.
Hi Ezhilkumar
Thank you for your reply.
Actually my size of particle is 2.5µm and density is 850 kg/m3.
What is your density of particle?
I am interested in particle mass concentrations not in particle trajectories.Since I am very new to fluent can you please explain on how to do the mass concentration analysis of PM in fluent ?
Looking forward to your reply
Hi Mithresh
Sure will help you.
To your knowledge,even I am very new to CFD-FLUENT and I trained my self with the tutorials available online.
So, now I am under going training courses, as I cant work with these available tutorials for my research purpose because you have to be very specific in defining your equations as said Mr.Jyoti and knowledge on what is happening in FLUENT back-end.
What ever the data your feeding, FLUENT will give you the results but we need a knowledge to interpret and validate the results.
If your interest in bound by your project results, then you may work with getting suggestions and running the software by trial and error methods and tutorial videos.
Have you goan through youtube tutorials related to your work for basics, if not will share few tutorial related to your work for basics and if you have queries, you can ping me?
Hi Mithresh
reply to your PM density.
Have referred many journals, books and found that the density of PM is 2.5 g/cm3 irrespective of size and shape of any aerodynamic particle.
How did you arrive as 850 kg/m3 for PM2.5?
are you defining them w.r.t concentration?
Can you please explain me?
I have arrived at the particle density of 850 kg/m3 based on various literature reviews. Can you suggest me some tutorials which are relevant to this Eulerian and drift flux models..?
yes will share one by one.
1. CFD - Fluent - HVAC analysis - Indoor
https://www.youtube.com/watch?v=YFLga5Vxwo8
Use the above tutorial for basics. Avoid solar radiation input and use your choice of inputs.
For feeding air pollutant data use the below link
https://www.youtube.com/watch?v=LSoQDmz9tyM
https://www.youtube.com/watch?v=eGExRyNH5DI
I think the above said links may help you to some extent.
Mithresh
better you ping me to my mail for future communication if any.
Hi Ezhilkumar
Thank for your concern. I will contact you for future communication through mail.
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