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-   -   Surface inejction- steady state - mass flow rate (http://www.cfd-online.com/Forums/fluent/96555-surface-inejction-steady-state-mass-flow-rate.html)

CFD-student January 25, 2012 13:40

Surface inejction- steady state - mass flow rate
 
Hi,

This is the first time i am using the DPM model in Fluent. I have some questions regarding the injection type: "surface injection". My simulation is a 1-way coupled steady state simulation where i resolve the flow field first and then carry out the trajectory calculation decoupled with the flow field. I have created a surface for injecting particles such that i go a uniform distribution of injections points.

What I wonder is the following:

1. How is the number of particles/parcel determined in this steady state simulation? Is it only 1 particle/parcel or is the total mass flow rate in some way distributed over the injected parcels?

2. In this kind of decoupled simulation where the particles dont affect the flow field or each other in any way is there any meaning to the concept solids volume fraction?

3. In general when fluid and solids have the same velocity is ok to estimate the solids volume fraction from the projected area of all particles in a injection zone divided by the injection zone surface area? Is it a better idea to calculate the volume occupied by particles as the mass flow rate multiplied by the residence time and divided by particle density in a given volume divided by the volume of that space?


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