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s_baghalian December 27, 2010 16:28

Gidaspow model
i am modeling a domain with 2 phases. one phase is water and other phase is dispersed solid. i selected Gidaspow for drag coefficient but it doesn't run and one error occur. when i select Schiller Naumann, program run but its results is incorrect. do you know that why this model don't run with Gidaspow model?

pannsave December 27, 2010 17:34

Could you specify the more details of your problem,
What is the solid volume fraction and mean particle size in your case
What was the error ..

s_baghalian December 27, 2010 17:46

yes, of course. volume fraction of sand is 0.73 and mean particle size is 1.28 mm. i selected these options in domain:
maximum packing=0.62
restitution coeff= 0.8
fluid models= inhomogeneous
for particles:
kinetic theory is on.
granular temperature model= algebraic
radial distribution = Gidaspow
turbulence= laminar
solid bulk viscosity,shear viscosity and pressure model= kinetic theory
drag coefficient= Gidaspow
program don't run and no result file error is shown.
do i define other option for remove this error and run it?
do i define minimum volume fraction for it?

pannsave December 27, 2010 19:41

Could you check whether your simulation run without an error when kinetic theory model is off and use simple model of gidaspow for solid pressure.

May be problem with the prediction of granular temperature value and check it
Sometimes they may have unphysically large granular temperatures where the regions of low solid particle volume fraction.
so in order prevent this, specify an upper bound for the granular temperature

s_baghalian December 28, 2010 01:20

thank you very much for attention you. yes, i has run it without kinetic theory but results are incorrect.
how i can specify an upper bound for the granular temperature?

pannsave December 28, 2010 04:37

There is option for specifying upper bound of granular temperature in Kinetic theory model ie., Maximum granular temperature option

s_baghalian December 28, 2010 07:43

what is the value of it? i don't find its value.

pannsave December 28, 2010 11:26

I dont know extactly the range of maximum granular temperature, May be you can look it in the literature

I prefered to give in the range of 0.01 m2/s2

Orlese you try different values to ensure the simulation results are independent of maximum granular temperature

s_baghalian January 1, 2011 07:30

In this model, i turned off kinetic theory, and used Gidaspow model with compact modulus = 100 for solid pressure. Is this model suitable for modeling Water and sediment?
i modeled it inhomogeneous, is it correct or i should model it homogeneous?

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