Does anyone out there have experience modelling hydrocyclones? In particular, I would like to know how well you do in predicting the pressure drop and how you go about modelling the air core?

I set the boundary condition of the outlet to opening and the air core developed automatically.

That is an interesting approach. Do you then run the calculation as multi-phase using an Eulerian/Eulerian approach?

I was thinking of adding some air to the inlet as I believe that this is often the air that comes to the center in a hydrocyclone (unless the liquid has been de-aerated). The trouble is that the amount of air required is unknown apriori.

How well do you predict the pressure drop through the cyclone with this approach?

I have seen other people locate the gas/liquid interface at the location of zero axial velocity within the hydrocyclone, but this doesn't seem like the best approach to me.

Any more of your thoughts would be most welcome.

I run the calculation as multi phase with and without the homogeneous model. I think that the amount of air in your feed is usually very small. I locate the interface with a volume fraction of 0.5.

I didn't measure the pressure but you could look at:

http://hugin.aue.aau.dk/~granly/202/msc.php

you can download a theses from denmark there and these guys used LDA and pressure measurements.

Thanks Eike, that looks like one of the better references that I have seen for these types of flows I will take a closer look tomorrow.

Hi Eike,

I looked at the thesis that you recommended. Although the geometry of the swirl atomizer is quite different from a hydrocyclone, I still found it a great reference.

Even though the authors used LES and predicted the air core diameter quite well, they were still underpredicting the pressure drop of their device by a factor of 3!

I wonder if you or anyone out there knows why it is so difficult to predict the correct pressure drop in these swirling flow devices (hydrocyclones, atomizers)? There must be one important factor that I am not considering ... is there a trick to the BC's

Let me know what you think. How do your predicted pressure drops match up with experiment?

[asifmohammad7]

Plz tell me how to locate an air liquid interface in hydrocyclone in fluent.....................

[asifmohammad7]

HI
IN my simulation air core is not forming so plz tell me what should i do so that i can predict the air core.