How can i approximate Darcy coefficient and Forchheimer coefficient?

Not sure how one would 'estimate' the values.  Generally you'll need experimental data capturing the curve of velocity versus pressure drop across the porous medium - in your case likely the 'stack' of foam plus perforated leather

Not sure how one would 'estimate' the values.  Generally you'll need experimental data capturing the curve of velocity versus pressure drop across the porous medium - in your case likely the 'stack' of foam plus perforated leather

i want to replace the experiment with analysis.

I'm trying to use some formulas like this.

https://holzmann-cfd.com/community/blog-and-tools/darcy-forchheimer

i want to replace the experiment with analysis.

I'm trying to use some formulas like this.

https://holzmann-cfd.com/community/blog-and-tools/darcy-forchheimer

 

Yes - that page also has a velocity versus pressure drop curve (though only two data points).  Not sure what you would do without that information

Yes - that page also has a velocity versus pressure drop curve (though only two data points).  Not sure what you would do without that information

i will get pressure drop data from Flow analysis. with different velocity. 
it will be tough but gonna make fine mesh geometry about leather layers.

i will get pressure drop data from Flow analysis. with different velocity. 
it will be tough but gonna make fine mesh geometry about leather layers.

Once you have velocity vs pressure drop - you can use HyperWorks CFD to determine the coefficients - as in this tutorial:
https://help.altair.com/hwcfdsolvers/acusolve/topics/tutorials/acu/acu_6500_intro_cfd_r.htm#acu_6010_intro_cfd_r
That calculator will be added to SimLab at a later date

This is the main description page for the Porosity Model in the Command Reference Manual:
https://help.altair.com/hwcfdsolvers/acusolve/topics/acusolve/porosity_model_acusolve_com_ref.htm

Not sure how one would 'estimate' the values.  Generally you'll need experimental data capturing the curve of velocity versus pressure drop across the porous medium - in your case likely the 'stack' of foam plus perforated leather

You could  find pressure drop correlations for different porous media, screens and etc from here. Handbook of hydraulic resistance: https://www.nrc.gov/docs/ML1220/ML12209A041.pdf