[ss ss17]

Recently I was reproducing the Eulerian two-fluid fluidized bed with buried tubes, the purpose of which is to measure the convective heat transfer coefficient around the buried tubes, but after trying several papers I found that all of them have a layer of gas at the bottom of the buried tubes, while the bottom of my buried tubes are full of solids. My model setup is all consistent with the original literature. Does anyone know why this is?
https://doi.org/10.1016/j.ijheatmass...er.2019.06.058

[Martin_Sz]

Several factors can influence the presence or absence of a gas layer at the bottom of buried tubes in a Eulerian two-fluid fluidized bed simulation:
* Minimum Fluidization Velocity: Ensure your gas inlet velocity exceeds the minimum fluidization velocity (Umf) for the specific particle size and shape used in your simulation. Below Umf, the gas won't have enough force to overcome interparticle forces, resulting in a dense packing of particles around the tubes.
* Packing Arrangement: The initial packing of particles within the bed can affect gas distribution. Experiment with different packing techniques (e.g., random packing, close packing) to see if it influences gas holdup near the tubes.
* Drag Models: The selection of drag models in your Eulerian two-fluid model can impact how the gas and solid phases interact. Try using different drag models (e.g., Schiller-Naumann, Syamlal-Obasi) to see if it affects the gas layer formation.
* Boundary Conditions: Double-check the boundary conditions at the bottom of the bed. Ensure they allow for gas flow and aren't restricting gas from entering the region around the tubes.
* Mesh Resolution: A finer mesh resolution near the tubes might better capture the gas-solid interaction and potentially resolve the formation of a gas layer.
If you've addressed these points and still encounter the discrepancy, consider consulting the specific literature you're referencing. Look for details on the simulation setup, drag models, and boundary conditions used by the authors. This might reveal additional insights into their model and potentially help you achieve similar results.

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https://howtooansys.blogspot.com/202...bsence-in.html

[ss ss17]

thank you martin,
Although all the settings of my model are the same as in the original literature.....