Seeking Insights on Modeling Low-Concentration Sand Slurry Flow in Horizontal Pipes

rshettCFD · December 18, 2023, 13:47

Hello Community,

I'm currently engaged in a project involving the simulation of low-concentration sand slurry flow through horizontal pipes. This process is characterized by transient sand injection, which occurs after the water phase has achieved a fully developed state. My approach utilizes the k-w SST turbulence model.

The system I'm working with features a pipe that is 12 meters long and has a diameter of 0.0508 meters. Both experimental and analytical models suggest that the sand should remain in a heterogeneous suspension. However, in my simulations, I'm observing a quicker settlement of sand compared to its transport by the carrier phase, which is contrary to expectations.

Efforts to rectify this include tweaking various parameters such as the specularity coefficient and experimenting with the k-epsilon turbulence model, but these modifications haven't been successful in maintaining the sand in suspension.

I have two primary queries where I would greatly appreciate your expertise and suggestions:

How crucial is mesh refinement in this context, and what strategies can I employ to balance the need for a fine mesh with computational efficiency? Would enhancing the mesh resolution significantly impact the accuracy of simulating settling slurries?

When defining the material properties for sand in the simulation, what viscosity values should be considered?

Your insights and recommendations on these matters would be invaluable to my research.

Thank you for your time and assistance.

Best regards,
Rishi

rshettCFD · December 19, 2023, 00:56

I believe I've found the solution to the issue I was experiencing. The root cause appears to be the surface roughness setting, which was initially set to zero. By adjusting the roughness height to the diameter of a particle and setting the roughness constant to 0.75, I observed that the pressure gradient increases, likely due to enhanced friction. This change results in a greater drag force on the particles.

I welcome any additional advice for fine-tuning the model.

Also, I'm currently using the default value for the granular temperature of the sand phase, which is 0.0001 m²/s². I'm wondering if this should be adjusted. Any suggestions on this would be appreciated.

Best regards

December 18, 2023, 13:47	Seeking Insights on Modeling Low-Concentration Sand Slurry Flow in Horizontal Pipes	#1
rshettCFD New Member rshettCFD Join Date: Sep 2023 Posts: 4 Rep Power: 2	Hello Community, I'm currently engaged in a project involving the simulation of low-concentration sand slurry flow through horizontal pipes. This process is characterized by transient sand injection, which occurs after the water phase has achieved a fully developed state. My approach utilizes the k-w SST turbulence model. The system I'm working with features a pipe that is 12 meters long and has a diameter of 0.0508 meters. Both experimental and analytical models suggest that the sand should remain in a heterogeneous suspension. However, in my simulations, I'm observing a quicker settlement of sand compared to its transport by the carrier phase, which is contrary to expectations. Efforts to rectify this include tweaking various parameters such as the specularity coefficient and experimenting with the k-epsilon turbulence model, but these modifications haven't been successful in maintaining the sand in suspension. I have two primary queries where I would greatly appreciate your expertise and suggestions: How crucial is mesh refinement in this context, and what strategies can I employ to balance the need for a fine mesh with computational efficiency? Would enhancing the mesh resolution significantly impact the accuracy of simulating settling slurries? When defining the material properties for sand in the simulation, what viscosity values should be considered? Your insights and recommendations on these matters would be invaluable to my research. Thank you for your time and assistance. Best regards, Rishi

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December 19, 2023, 00:56		#2
rshettCFD New Member rshettCFD Join Date: Sep 2023 Posts: 4 Rep Power: 2	I believe I've found the solution to the issue I was experiencing. The root cause appears to be the surface roughness setting, which was initially set to zero. By adjusting the roughness height to the diameter of a particle and setting the roughness constant to 0.75, I observed that the pressure gradient increases, likely due to enhanced friction. This change results in a greater drag force on the particles. I welcome any additional advice for fine-tuning the model. Also, I'm currently using the default value for the granular temperature of the sand phase, which is 0.0001 m²/s². I'm wondering if this should be adjusted. Any suggestions on this would be appreciated. Best regards