What is the solid volume fraction in the BC means?

MFiX
#1

For example, if I use mass flow inlet in BC, and specify solid mass flow rate=3e-5 kg/s. The fluid also uses mass inlet and fluid mass flow rate=1e-4 kg/s
Then I give 0.01 volume fraction to the solid phase, the gas phase will be automatically calculated as 0.99.

What is the 0.01 means? Does it mean that I only has 0.01*3e-5 kg/s mass flow goes into the reactor?

This question has harassed me very long time. I will be grateful if someone kindly answering my question.

====update====
Sorry for typo, it is volume fraction instead of mass fraction

#2

As you noted, this is volume fraction, not mass fraction. If you specify a solids mass flow rate of 3e-5 kg/s, with volume fraction of 0.01, then the solids velocity at the inlet will be computed so the product of the solids volume fraction, density, inlet area and inlet velocity equals 3e-5.

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#3

Thank you for your replying.

so, if
density=300kg/m3
inlet area=1e-5m2
mass flow rate=3e-5kg/s
volume fraction=0.01
then the inlet velocity can be calculated as
3e-5 / (300 * 0.01 * 1e-5)=0.333 m/s
Am I right?

If in an intuitive explanation:
keeping the 3e-5kg/s unchanged, increase volume fraction from 0.01 to 0.05 means that the particles coming in more slow and stick close to each other, but the number of particles coming in per seconds is not changed.

#4

I get 3e-5 / (300 * 0.01 * 1e-5)=1.0 m/s but this is the idea. Yes, increasing the solids volume fraction will decrease the inlet velocity to maintain the same mass flow rate.

If you look at the standard output (in the console), you will see something like:

    No. particles injected per solids time step =  1.09896699E-02
    No. particles injected per second =        611
    ```

(this is not your example)
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