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-   -   droplet separation off a particle in turbulent stream (http://www.cfd-online.com/Forums/main/122590-droplet-separation-off-particle-turbulent-stream.html)

anonymous_89 August 22, 2013 13:40

droplet separation off a particle in turbulent stream
 
Hi,

I am looking to develop the following system in a different platform, but I could use a little help from anyone with a CFD background and good understanding of particulate flow. I would very much appreciate the help in making sense of this.

The following is the system I am looking at.

A droplet resides on a particle. The size of the particle is 100 microns and the droplet is around 1-10 microns. The system is in a plug flow reactor with low slip velocity ( U_particle - U_gas is not very high). The Reynolds number of the gas in the reactor is very high (10^5) (calculated using gas velocity and diameter of the reactor) while the particle Reynolds number is very low (10^-2) (calculated using slip velocity and diameter of particle).

I would like to know the shear rate on the particle, so as to see whether the gas flow can separate the droplet sitting on it by overcoming the adhesion force (droplet contact angle is very high). (Drag force on the droplet is not sufficient alone)

My question is, would it be correct, due to the smaller slip velocity and small Particle Reynolds number, to model the flow around the particle as stokes flow? Can i make any assumptions to simplify this problem in the Navier Stokes eqn.

If I know the boundary layer thickness over the particle, i could calculate the shear rate on the particle. how can i go about this?

Thanks

anonymous_89


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