Request for Assistance with Circulating Fluidized Bed Reactor Simulation in MFIX

[sergioefrain]

Dear Developers

My name is Sergio González S., and I am working on a simplified simulation of a circulating fluidized bed reactor (CFBR) using MFIX 2024 software. My objective is to model a rectangular CFBR where air and solid particles enter through the bottom inlet, rise through the reactor, and are recirculated back to the inlet after exiting through the top outlet. This configuration aims to replicate the particle recirculation and gas flow characteristic of circulating fluidized bed reactors, though in a simplified design.

I have attempted to implement this recirculation loop in MFIX but am encountering some challenges. Below are specific areas where I would appreciate your guidance:

1. Boundary Condition Configuration for Recirculation Loop: Is it possible in MFIX to define a boundary condition where the top outlet is directly linked to the bottom inlet to simulate flow recirculation? I would like to know if MFIX supports this configuration or if there are recommended methods for achieving this type of recirculation.
2. Implementation of Flow and Solids Recirculation: I am exploring how to capture the flow properties at the top outlet (air velocity, particle loading) and apply them to the bottom inlet at each time step. I would appreciate any recommended methodologies or documentation that describes how to implement this logic in MFIX.

Any guidance, additional documentation, or configuration examples that could help me implement this recirculation simulation in MFIX would be greatly appreciated.

Thank you very much for your time and assistance.

Kind regards,
Sergio González S.

cfr_Ser_2d.mfx (7.6 KB)

[sergioefrain]

Hello, I hope you are well. Does anyone know anything about the subject I am talking about?

[cgw]

Hi Sergio.

Searching the forum for “circulating” turns up a few things including these:

Route to simulate a circulated leaching column

Hi, I am going to simulate a leaching system where the solutions will be collected and reinject to the system. The solutions keep passing the particle bed in a column with species exchange between the fluid and solid phase. The outlet fluid will be collected to reject into the column. Since the species concentration changes each time, I need to continuously change the fluid inlet property and mock them to the fluid outlet surface. Any suggestions to simulate this process in the MFIX platform…

How to count the number of parcels in the solid outlet, and then inject the same number of parcels to the solid inlet in MFIX-PIC?

When you sum the particles number, you should do like: totP= PIP - IGHOST_CNT CALL GLOBAL_ALL_SUM(TOTP)

Perhaps someone else can provide more assistance.

– Charles

[jeff.dietiker]

This is not natively supported, but this may be achieved with custom code (user-defined-functions, or udfs).

One possible strategy would be to start with monitors, to capture the outlet flow properties. Then you would use this information to reset the MFiX keywords that control the mass inlet BC. I have not tried that. Will be tricky if you have backflow.