Question about DPM velocity and Total flow rate

mercury1997mercury1997 Member Posts: 13

Hello:

I'm a beginner for DPM function in ansys fluent. I want to ask a few question about DPM settings:

  1. In the "point properties" what is the meaning of velocity and total flow rate. It's that the "velocity" is use to define the Initial velocity of the particles? And what is the meaning for the total flow rate (especially for a single point)?
  2. Is the velocity and total flow rate don't connect with the set up on the inlet boundary condition(if iI use mass flow rate as a inlet boundary condition)?
  3. How should I define the inject of particle without any initial velocity. Set 0 m/s and 0 kg/s for velocity and mass flow rate can't get any result for particles tracking. Should I set up both value as a vey small number, for example "1e-15"

Hope you could answer my question, Thank you.

Many thanks

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Answers

  • mercury1997mercury1997 Member Posts: 13

    Hello:

    I'm a beginner for DPM function in ansys fluent. I want to ask a few question about DPM settings:

    1. In the "point properties" what do “velocity” and “total flow rate” refer to?

    2. Are the “velocity” and “total flow rate” have any relation with the set up what we define in inlet boundary condition? (Considering I define “Mass flow inlet” at the inlet of the whole structure mesh).

    3. Ideally I would not want to define any additional “velocity” and “total flow rate” to my particles in addition to what the inlet mass flow is.

    Hope you could answer my question, Thank you.

  • alainislasalainislas Morgantown, West VirginiaMember Posts: 61

    Hello @mercury1997


    DPM mass flow rate and DPM initial velocity are independent inputs for your point injection. Note that this is a discrete mass flow rate and not a continuous mass flow (m_dot = rho*vel*area is not valid), instead m_dot = # particles / sec * mass_particle. If you set your DPM mass flow rate you know the mass of the particle based on density and diameter, the # particles / sec (usually referred as the "strength") is the reciprocal of your particle time step.


    We have not specified any velocity here yet, so that's why you need that input too.

  • DrAmineDrAmine GermanyForum Coordinator Posts: 6,642

    Thanks @alainislas for the valuable answer

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