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 Batis August 27, 2010 22:37

Particle Tracking

Hi,
I have question about Particle Tracking Model.

Assuming that we have information about particle diameter, particle material density and particle mass flow rate, we can evaluate number of real particles flowing into the domain per unit of time. So, if we provide number of representative particles (Number of Positions) and we divide number of real particles by number of representative particles, we can evaluate how many real particles each representative particle reprasents. Dimension of these value is [1/unit of time], am I right?

But, in documentation it is written: "For steady state simulations, the Number of Positions parameter sets the total number of particles to be injected". So, it is a finite value? There is no constant number of particles flowing per unit of time?

Batis

 gravis October 4, 2010 08:00

As you said, in a steady state simulation you set a fixed number of tracks to represent the mean particle paths. In a transient simulation, you set the number rate of particle tracks injected - [1/unit of time].

In both cases, you also specify e.g. the particle size distribution and the total mass flow rate of all tracks.

So, in a steady state simulation, you don't directly specify a constant number of particles flowing per unit of time. However, indirectly you specify the mass flow rate for each particle track. Consequently, by specifying the particle size distribution you also are indirectly specifying the number rate per track.

if you know the mass flow rate of particles you can calculate the mass flow rate per particle track. And if you know the size distribution it is possible to calculate the number of particles flowing per unit time.

To answer your question, yes there is a constant number of particles flowing per unit time, provided that you specify a mass flow rate and a particle size distribution.

 Batis October 6, 2010 15:20