[ravitejakatragadda]

I am modeling the grille and radiator in the under hood of a car using Ansys FLUENT on Ansys Workbench. I modeled grille and radiator as porous media (In addition radiator is modeled as heat exchanger). The user inputs required for porous media are inertial resistance factor and viscous resistance factor. For that I need to have experimental data of Velocity and Pressure Drop across the porous component (Grille and Radiator in this case)

Could anyone recommend values for the
1. Inertial Resistance Factor
2. Viscous resistance Factor
(Or)
Provide any experimental data for Velocity Vs Pressure Drop for the two components.

Any help in this regard is appreciated.

[m zahid]

hi, have you find answer ? i want to know about the method of finding inertial and viscous resistance for modeling vegetation as porous media.if you have some material or link please share with me .
thanks

[NgoIchSon]

Hi,

I am studying on multiscale CFD simulation of carbon fiber impregnation process by thermoplastic matrix.*

In Brinkman equation: dp/dx = (mu/k)u + beta*rho*u*u, the first term on the right hand side is Darcy or viscous component, while the second term is non-Darcy component. The viscous resistance is 1/k where the beta is inertial resistance.*

According to several refs. such as*Higdon, J. J. L., & Kojima, M. (1981);*Dake, L. P. (1983), the non-Darcy is negligible at low flow velocities and generally omitted from liquid flow equations. Thus, taking into account the inertial term is depend on your flow (gas or liquid, fast or slow)

In Fluent, you can estimate the viscous resistance by Ergun equation (Fluent theory guide) which related to unit length and porosity of your porous media geometry:
Viscous resistance: 1/K = (Dp*Dp/150)*(epsilon^3)/(1-epsilon)^2
Inertial resistance: C2 = 3.5/Dp*(1-epsilon)/(epsilon^3)
where Dp is mean diameter of particles in porous media, epsilon is porosity.

In addition, you also can apply Forchheimer equation for flow through fibrous porous media by replacing Dp by sqrt(K) in C2 equation.

Regards,

Son

Refs:

Dake, L. P. (1983). Fundamentals of Reservoir Engineering: Elsevier Science.

Higdon, J. J. L., & Kojima, M. (1981). On the calculation of Stokes' flow past porous particles. International Journal of Multiphase Flow, 7, 719-727.

[ENGRTAHIR]

I am working on simulation of combustion in micro combustor with n-heptane as fuel.
If i use rough mesh with 0.4mm i get good result and it can be compared with experiment result, but if i use fine mesh with 0.1mm, the solution diverge.
Can anybody help me

[sankalpjain]

Originally Posted by ENGRTAHIR

I am working on simulation of combustion in micro combustor with n-heptane as fuel.
If i use rough mesh with 0.4mm i get good result and it can be compared with experiment result, but if i use fine mesh with 0.1mm, the solution diverge.
Can anybody help me

Try checking the quality of the mesh. It often happens that with refining the mesh some elements become low quality. Check the skewness and try implementing a structured mesh. Also, when is the solution diverging ? is it diverging soon after it starts or is it diverging after significant number of iterations ?

[ENGRTAHIR]

Originally Posted by sankalpjain

Try checking the quality of the mesh. It often happens that with refining the mesh some elements become low quality. Check the skewness and try implementing a structured mesh. Also, when is the solution diverging ? is it diverging soon after it starts or is it diverging after significant number of iterations ?

the mesh skewness is less than 0.6. and it diverge after some iteration.
Do you have udf for porous medium or mass transfer