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Atholl August 26, 2002 05:07

Hi all,

I've defined an injection (i.e. particle density, diameter and position in my geometry) using previously converged case & data files of horizontal two-phase flow in an annulus. After some preliminary sessions of playing around with the settings, I've found a couple of problems:

1) My geometry length is around 6m, but no matter what settings I seem to alter, the particle track terminates around half of the length. What's wrong here?

2) When I alter the particle diameter, small diameters (c. 0.0001m) show the particle staying around the low side of the annulus (where it was defined initially). However, if I change the diamter to something larger (i.e. 0.1m) the track shows the particle being lifted up from the low side to the top side. Obviously, the larger the particle, the less likely it is to be lifted or dragged along by the fluid, so why am I getting this contradictory result?

Thanks in advance,


Shiping Liu August 26, 2002 14:07

Re: Injections
For the question 1,I think you might set a too small step number or too short time.

Atholl August 27, 2002 03:54

Re: Injections
Yes, you are right: I altered some of these settings and it fixed the problem. Thankyou!

Has anyone had any experience with defining injections? I want to find out if a spherical particle of a certain diameter and density will be moved by the prevailing flow field. Is the injection method the correct way to go about this?

I know if the fluid velocity is insufficient, the particle will not move. At higher velocities, the particle may roll, slide or bounce along, and at even higher velocities, the particle will be lifted up into suspension. Can Injections give me this information?

Thanks again in advance


xjrocket August 27, 2002 10:38

Re: Injections
Maybe u would try to calculate Saffman Lift Force.

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