Determination of stationary region boundary in multiple reference frames method in a mixing system agitated by Helical Ribbon Impeller using CFD

Document Type : Full Lenght Research Article


School of Chemical& Petroleum and Gas Engineering, Semnan University, Semnan, Iran.


The multiple reference frames (MRF) method is the most suitable method to
simulate impeller rotation in mixing systems. Precise determination of stationary
and moving zones in MRF method leads to accurate results in mixing performance.
In this research, the entire volume of mixing system was divided into two zones.
The kinetic energy values were used to distinguish the zones with different
velocities. The low-velocity zones, close to zero, were considered as the stationary
zone and higher velocities were considered as the moving zone. The standard
geometrical parameters were used for mixing system. The axial velocity and axial
flow number were compared with literatures for validation. The values for
dimensionless diameter of stationary zone at different Reynolds numbers were
achieved for Newtonian and non-Newtonian fluids that are in agreement with
values applied in literatures. The results show that the dimensionless diameter of
stationary zone decreases as Reynolds number increases.


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