[CFD] Eulerian Multi-Phase Modelling

[CFD] Eulerian Multi-Phase Modelling

An introduction to Eulerian multi-phase modelling in CFD. Eulerian multi-phase modelling is available in most mainstream CFD codes (OpenFOAM, Fluent, CFX, Star etc). The following topics are covered in the video:

1) 0:37 What are dispersed-continuous and continuous-continuous phase interactions?

2) 5:02 What are the Eulerian multi-phase model equations?

3) 12:29 What is inter-phase drag and how is it accounted for?

#multiphaseflow #eulerianmultiphase #cfd

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Some Useful References:
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1) ANSYS Fluent Theory Guide
16.5.3 Conservation Equations

2) ANSYS CFX Theory Guide
5.5.2 Interphase Drag for Particle Model

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Disclaimer
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The methods, algorithms, equations, formulae, diagrams and explanations in this talk are for educational and demonstrative purposes only. They should never be used to analyse, design, accredit or validate real scientific / engineering / mathematical structures and flow systems. For such applications, appropriate trained, qualified and accredited (SQEP) engineers / scientists should be consulted along with the appropriate documentation, procedures and engineering standards. Furthermore, the information contained within this talk has not been verified, peer reviewed or checked in any way and is likely to contain several errors. It is therefore not appropriate to use this talk itself (or any of the algorithms, equations, formulae, diagrams and explanations contained within this talk) as an academic or technical reference. The reader should consult the original references and follow the verification and validation processes adopted by your company / institution when carrying out engineering calculations and analyses. Fluid Mechanics 101 and Dr. Aidan Wimshurst are not accountable or liable in any form for the use or misuse of the information contained in this talk beyond the specific educational and demonstrative purposes for which it was intended.

[hamedmehrvlogs]

That's an amazing video mate! Especially that mention that, the dispersed-continuous and continuous-continuous interaction differs in how we define the interfacial area per unit volume. It was super helpful.

[MalcolmAkner]

Damn, you are such an expert in explaining this in a way where it feels simple and approachable. Excellent pedagogic skills Aiden!

[engineersacademy]

Appreciate alot.. One of the best CFD masters on YouTube.
Really very informative and clear

[tusharthorat]

Great video. Simple and effective. It would be great if you can post a video on combustion models.

[mihirmakwana]

Hi Aidan. This video was very informative. A video on Lagrangian Multiphase model along with a comparison to Eulerian will be good sequel to this one. Cheers :)

[RichardDuneSJTU]

Thanks for your very detailed introduction.

[hydrokbar]

i think thanking is not sufficient for your efforts...i really mean it

[HaithamAhmed-kryl]

Really, Thank you for this valuable video. Go ahead ! We are waiting your new videos.

[akhileshwarsingh]

Today, I watched this lecture and subscribed your channel. Your lecture was compact with quality. I am hoping some lecture related to interface tracking in multi-phase. I mean VOF model with explicit function. Thanks for this video.

[kaushalsorte]

Hello Aiden. This explanation was very helpful. Thanks.
Could you please make a video on Volume of Fluid approach as well? Thanks in anticipation.

[thunderza]

So in continuous-continuous flows, we don't normally model the ''surface drag'. For two incompressible fluids, the interface velocity is continuous. ie there is no phase velocity difference. However, I am talking about the single-fluid approach - which is the standard approach for fuel/tank slosh - maybe it is different in the multi-fluid approaches.

I have never header of using the gradient as a stand-in for the surface area. I mean there is no mathematical reason for the gradient of the volume fraction to be related to the surface area, they are spatially orthogonal quantities. The gradient is used frequently as the interface normal (when normalised). For an algebraic VOF scheme, knowing the surface area of the interface is next to impossible, but for geometric methods, it is implicit in the scheme.

Sorry perhaps because I work building these models I am being a bit critical. I love this channel in any case. Please don't take it personally, just a bit of confusion on my side. :D

[ryanlin]

Thanks for your good teaching really. It's very literally. hope for next video about VOF model!

[mickbatti]

Nice video, thanks. However, in the drag model, please note that what counts is the frontal area of a sphere, not its surface area. The Cd of a body is generally defined using its frontal area. Therefore, equation 12 turns out to be 3/2*rp/dp, not 6*rp/dp

[hassanazizi]

Great explanation. I would request you to kindly give an insight to the modelling of mass transfer mechanisms between the different phases in your next video.

[mohamedelbouti]

Thank you for this amazing video, i just have a question regarding the VOF and mixture models, in Fluent when choosing VOF model we have also the option to choose dispersed interface, and when choosing mixture model, we have the option to choose sharp/ dispersed interface, could you please give more details about that ? Thanks

[ashishtiwari]

Good work. Your explanations are simple enough to understand. Keep continuing with the good work. I am a masters student in CFD so it sounds familiar. I would request you to make videos on hybrid RANS LES models and probably on parameters such as q criterion and vorticity.

[Lunamycat]

Great video Aiden. What model should I use if we have both continuous-continuous and dispersed-continuous interactions in the same flow system?

[samueltorres]

Thank you for the clear explanation! For a project I need to simulate the dynamics and concentration profiles of polydispersed nanoparticles in a microfluidic and I was considering to approach the model using the Euler-Euler method in COMSOL (treating them as a dispersed phase), also introducing LES equations. Can this model be considered for nanoparticles? Do you think this approach could work?

[danieltarraf]

Thank you, may I ask a question ?
Assume we are spraying water in hot air (~1000c). some of the water will evaporate. Now, At the beginning of time t=0 we know r_vapor = 0 every where (we don't have vapor yet). If we consider the equation (4), r_vapor will not change as time progress (r_vapor = 0 for every time step). Is this correct ? Should not we add a volume fraction term (representing the transfer from water to vapor) as we did to the continuity equation ?

[Miao_zai]

Hello Aidan At 20:50 in the video, is that continuous-continuous interaction Cd is calculated same as Dispersed-continuous interaction Cd? All using the Schiller model? Thanks