Porous media pressure drop not agreeing with the experimental values

Jmaes · June 3, 2023, 17:32

Hello everyone,

I have the experimental pressure drop data through a porous media and I trying to simulate it in fluent. My geometry is in the attached image. The brown part is the porous zone and the entire thing would be vertical. I found the porous media parameters using data and applied it but the pressure drop I am getting is way lower than that in experiment. Where could I be going wrong?

I tried to simulate the pressure drop in just the inlet part until a few millimeters after the channels end and tried to replace is with just one section of equivalent diameter and a porous zone but the pressure drop in this case was higher.

I've been trying to do this for the past two days but I am getting no results. Please help me. You can find the parameters I used in the attachments.

MKuhn · June 8, 2023, 08:54

What are your material properties? Calculating with a constant density could be a reason.

Jmaes · June 8, 2023, 09:04

The fluid is water and I don't suppose I need to specify the porous medium material, do I?

MKuhn · June 8, 2023, 09:13

No, I don't think so either. Sorry porous media is not my field.

Jmaes · June 8, 2023, 09:45

Thanks anyway

Jmaes · June 8, 2023, 11:04

Hello semj,

Thanks for the insight. Is there a way to choose a specific equation? I always thought that fluent does this on it's own.

I am aware that the flow through a packed bed is modelled using the Ergun's equation and you can find the viscous resistance and inertial resistance parameters in one of the images I attached in my original question.

Furthermore, you can find the geometry in one of the images as well. What you see is the fluid volume extracted using SpaceClaim. The porous zone is activated carbon particles of average diameter of 0.7 mm and the diameter of the middle sector is 31.92 mm. The length of the porous zone is 3cm. The setup is vertical, in that, the porous media would be at the bottom though It doesn't have to be at the bottom, it can be half way through the pipe.

I think the reason the experimental data doesn't match with the simulated data could be due to the reduced velocity by the time the water reaches the porous media. In the actual experiment, the water starts to fill up in the middle sector and acts pretty much like a bottle with a hole at the bottom. However, I do not have any equipment that to measure the velocity of water right before it reaches the porous zone

June 8, 2023, 09:13		#4
MKuhn Senior Member Moritz Kuhn Join Date: Apr 2010 Location: Germany, Dresden Posts: 218 Rep Power: 17	No, I don't think so either. Sorry porous media is not my field. Jmaes likes this.

June 8, 2023, 09:45		#5
Jmaes New Member James Ranawadia Join Date: Apr 2023 Posts: 15 Rep Power: 3	Thanks anyway MKuhn and semj like this.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Multiphase Porous Media Flow - Convergence Issues	VT_Bromley	FLUENT	8	May 30, 2024 03:59
viscosity udf don't use correct temperature and strain rate	rezvani	Fluent UDF and Scheme Programming	8	May 27, 2021 06:40
FLUENT + porous media and direction angle	zog	FLUENT	2	August 11, 2019 10:47
lower pressure drop compared to experimental value in Two phase flow calculations.	Ash Kot	Fluent Multiphase	0	May 16, 2017 17:29
Hydrostatic pressure in 2-phase flow modeling (long)	DS & HB	Main CFD Forum	0	January 8, 2000 16:00

June 8, 2023, 08:54		#2
MKuhn Senior Member Moritz Kuhn Join Date: Apr 2010 Location: Germany, Dresden Posts: 218 Rep Power: 17	What are your material properties? Calculating with a constant density could be a reason.

June 8, 2023, 09:04		#3
Jmaes New Member James Ranawadia Join Date: Apr 2023 Posts: 15 Rep Power: 3	The fluid is water and I don't suppose I need to specify the porous medium material, do I?

June 8, 2023, 11:04		#6
Jmaes New Member James Ranawadia Join Date: Apr 2023 Posts: 15 Rep Power: 3	Hello semj, Thanks for the insight. Is there a way to choose a specific equation? I always thought that fluent does this on it's own. I am aware that the flow through a packed bed is modelled using the Ergun's equation and you can find the viscous resistance and inertial resistance parameters in one of the images I attached in my original question. Furthermore, you can find the geometry in one of the images as well. What you see is the fluid volume extracted using SpaceClaim. The porous zone is activated carbon particles of average diameter of 0.7 mm and the diameter of the middle sector is 31.92 mm. The length of the porous zone is 3cm. The setup is vertical, in that, the porous media would be at the bottom though It doesn't have to be at the bottom, it can be half way through the pipe. I think the reason the experimental data doesn't match with the simulated data could be due to the reduced velocity by the time the water reaches the porous media. In the actual experiment, the water starts to fill up in the middle sector and acts pretty much like a bottle with a hole at the bottom. However, I do not have any equipment that to measure the velocity of water right before it reaches the porous zone