How to define the mass flow rate in injection of DPM

- November 24, 2019 at 2:42 am
  
  mreza65
  Subscriber
  
  Hi. Could you please clear it below?
  
  For example in a microchannel, we have an inlet and outlet. In a single-phase mode I assume "Velocity inlet" as the condition of the inlet with a velocity of 0.45m/s. However, in the Discrete Phase Model, I choose surface injection and the surface is my the inlet. Now, I want to add "Volume Fraction" of particles as a second-phase. In the injection window, I have to specify the amount of mass flow rate. My question is here, is it correct to use the formula in the attached file?
- November 25, 2019 at 6:06 am
  
  DrAmine
  Ansys Employee
  
  As ANSYS staff we do not look into attachments.
- November 25, 2019 at 6:47 am
  
  mreza65
  Subscriber
  
  Hi Amine.
  
  I wrote the formula in the attached file because I cannot that here.
  
  I explain my problem statement here in detail.
  
  First, I want to decrease the temperature of a 2-D microchannel with water. Inlet velocity is 0.45m/s, inlet width is 0.2mm, density equates 995.7 kg/m^3.
  
  So, the mass flow rate is equal to 0.45x0.0002*1*995.7 (=0.089613).
  
  Then, I want to inject AL2O3 with a volume fraction of 0.03. I think that I can apply this fraction in Discrete Model in the mass flow rate of injection. Could you help me how can calculate it? I use the following formula;
  
  mass flow rate of particle= (volume fraction x density of particle x mass flow rate of water obtained above) / (density of water)=(0.03*3600*0.089613)/995.7
  
  Is it correct?
  
  Thanks in advance
- November 25, 2019 at 2:15 pm
  
  Rob
  Ansys Employee
  
  In the injections you'll see a mass flow: that is the mass of DPM material. If you want to inject a certain volume or mass fraction of particles you'll need to do the sums.
  
  If you're interested in a certain volume fraction then work out the inlet (fluid) volume flow rate and then calculate from there.
- November 26, 2019 at 3:56 am
  
  mreza65
  Subscriber
  
  Thank you.
- February 7, 2020 at 12:45 pm
  
  hero55
  Subscriber
  
  please mreza65 can share me how you calculate total mass flow to get 0.03 volume fraction
  
  and thank you
  
  Any help would be appreciated
- February 7, 2020 at 2:37 pm
  
  hero55
  Subscriber
  
  up
- February 7, 2020 at 3:17 pm
  
  Rob
  Ansys Employee
  
  Maybe read his post carefully? Volume fraction calculations are explained in most text books.
- February 7, 2020 at 8:39 pm
  
  hero55
  Subscriber
  
  sir rwoolhou here I dont understand you (If you want to inject a certain volume or mass fraction of particles you'll need to do the sums. )
  
  what did you mean (you'll need to do the sums) what sums?
  
  and thank you very much.

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