Fluids

Fluids

For Deriving Porous Media for using known Pressure loss how is the value of loss factor KL=0.5?

    • uditkumar007
      Subscriber

      Hello,

      In the Ansys manual for the value of C2 i.e inertial resistance, I happen to know the porosity of the medium.

      Suppose if the porosity of the medium is 25% i.e the medium has a 25% area to flow.

    • Karthik R
      Administrator
      Hello,nKl is the loss factor that generally is coming from correlations or experiments. You might be able to find this from the literature. nRegarding your second question - permeability is used to calculate the viscous resistance and not inertial resistance. The nomenclature used in Fluent is C1. Please look at the Users Guide for additional information on this. nKarthikn
    • uditkumar007
      Subscriber
      Hello Sir,nThank you for answering. nSir will the value of loss factor, KL be equal to 0.5 if I change the porosity i.e the area the flow through the medium? If not how can I calculate it?nSir is there any reference you can provide? nFor the 2nd part that's a mistake on my part. Sorry, Sir. I meant I have the porosity data of the medium. So how can I calculate the value of C2 in any other way? I don't have the data for pressure loss vs Velocity. nSince I have the permeability data too I can calculate Viscous resistance easily.Sincerely,nUdit.n
    • Karthik R
      Administrator
      Hello Udit,nUnfortunately, I don't have a handy reference I can provide. You might have to dig into the literature. There are many papers that estimate Kl with porosity. Many hydraulic loss textbooks and handbooks should have correlations. Based on what you are attempting to model, I'd strongly recommend that you look into the literature for this data. Once you have the correlation, you should be able to plug the porosity and estimate the value of Kl. This becomes your input. nIf you don't have an exact number, perhaps running a sensitivity test might at least give you an idea of how this factor would affect your overall simulation. But, to narrow down your results and get some physical conclusions, you will need to nail this parameter Kl.nI'm not aware of any other way to estimate this value (unfortunately).nI hope this helps.nKarthikn
    • uditkumar007
      Subscriber
      Thank You so much, Sir, for the suggestions. I look for the literature to find an appropriate estimate.
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