Fluids

Fluids

Multiphase DPM Simulation For Abrasive Particle

    • shubham_C
      Subscriber

      I am simulating a Multiphase flow with DPM particle interacting with primary phase of liquid...

      It is necessary for particle to remove the material from the surface of the wall, how i can simulate that?

      I have used Eulerian multiphase model with DPM both phases have 0.5 volume fraction in the simulation.

      Also which results i should look into for the definition of material removal from the surface of walls?

    • Rob
      Ansys Employee
      We have erosion models with DPM in Fluent, they're based on impact erosion. Abrasion tends to be shear related and you may need to use some UDFs with a suitable correlation. Note, DPM will not see the Eulerian granular phase unless you're using DDPM which won't then work well with the built in erosion models.
    • shubham_C
      Subscriber
      Thanks for the comment Rob...
      Rather than using DPM model, Should i go with Eulerian model and make the secondary phase which are abrasive particle as granular in Boundary conditions?
      I dont have any UDF for abrasion related phenomenon that's why i have asked which results should i look for which will provide me enough confidence to calculate shear removal rate?
      I was thinking that, making abrasive particle as granular in Eulerian model it will interact with primary semi-solid fluid like silicon polymer and provide the result based on shear stress at wall and dynamic pressure value...
      Let me know your response on this...
      I know, to have erosion model i have to go with separate DPM model in the simulation... But it is important for me to have interaction between the abrasive particle.
    • DrAmine
      Ansys Employee
      Should be possible with Euler Granular as mentioned in the help. That will account for abrasive effects and particle shielding effects. https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v211/en/flu_th/flu_th_sec_discrete_erosion_dense.html
    • shubham_C
      Subscriber
      Thanks for comment Dr Amine, but i cant see the link you have provided
    • Rob
      Ansys Employee
      This will help with link https://forum.ansys.com/discussion/22563/using-help-with-links
      You can set the granular phase, but we don't (yet) have a built in model for abrasive erosion. You'd need to work that bit out. Most (all?) of the data is available from Fluent, but you'd need to figure how how much of what values interact to calculate the material removal rate.
    • DrAmine
      Ansys Employee
      You can use the Erosion Models on top of Euler Granular: just create a dummy particle injection.
    • shubham_C
      Subscriber
      Thanks for the comment Dr Amine...
      What you are asking me to do is to create multiphase Eulerian model with two phase of semi-solid liquid and Abrasive particle in secondary phase.
      Also enable the DPM model in which i will create the Injection of Abrasive particle with constant velocity of semi-solid liquid present in primary phase.
      Use of DPM model to find the erosion at the wall and calculate the abrasive erosion caused by particle?
      Another question which arise is that, Secondary phase which is of abrasive particle with volume fraction 0.5 is coming in with Primary phase, so should I consider the volume fraction of secondary phase in the whole simulation ?
      From numerous literature of AFM process i come to know that, Use of granular pressure and strain rate of abrasive particle on the wall of domain also dynamic pressure helps to find the "Ra" value which is given as
      Please let me know what i am thinking is correct approach towards the problem...
      I want to solve the problem with maximum accuracy for entire solution of AFM process.

    • DrAmine
      Ansys Employee
      I did not ask for anything. If you want to account for abrasive effects and shielding you need either to Euler Granular or DDPM Model. With Euler Granular one will require a dummy injection (which does not inject anything). Again the link I shared and the Fluent User's Guide are of great help.
    • shubham_C
      Subscriber
      Thanks for comment Dr Amine...
      I have perform the Eulerian multiphase model with dummy injection and get the value of Wall shear due to Erosion...
      The link you have provided in which the empirical relation talks about E abrasive where value A and n which are empirical constant and velocity exponent are unknow...
      I have search many literature but didn't found the value of those variable...
    • Rob
      Ansys Employee
      They're material dependent, ie sand on steel will have different values to grain on plastic. There are papers etc on the subject, but we don't have data we can share. Try publications from DNV and Tulsa University as both do research in this field.
    • shubham_C
      Subscriber
      Hello Rob and Dr. Amine...
      i want to calculate the normal force exerted by granular particle to the surface of workpiece.
      As i am using an Axi-symmetric model for the simulation which wall stress value should i use to calculate the normal force?
      As i have seen in FLUENT result there no option for normal shear stress caused by particle. I have calculate the surface integral value of pressure but using that value for calculation of normal force is providing me incorrect value.
    • DrAmine
      Ansys Employee
      If using granular model (Eulerian) you have access to Pressure and viscous forces on walls. You might extract from there whatever you want to extract or just write an UDF or Fluent Expression to get what you want to get. The report will provide the force in x,y,z you need just to get the scalar product with normal to the wall.
Viewing 12 reply threads
  • You must be logged in to reply to this topic.