Validation Cases

Scientific reliability is key

Therefore, we prepared 5 validation cases to demonstrate the scientific reliability of CFDEM®coupling

CASES

CASE I
SETTLING SPHERE

Single particle is released in a cubic box and starts to settle under the influence of gravity.
Method: resolved CFD-DEM – cfdemSolverIB, i.e. no usage of drag force models.

Comparison of settling velocity:
simulation with CFDEM®coupling against results published by Pianet et al., Computers & Fluids 36 (2007), 359-375 shows a good match.

CASE II
ERGUN TEST CASE – FIXED BED

Fluid flow through a fixed particle bed – the Ergun equation describes the resulting pressure drop in dependence of the fluid velocity.
Since the particles cannot move, no fluidization can occur and the pressure drop increases linearly with increasing flow velocity.
Method: unresolved CFD-DEM – cfdemSolverPiso

Comparison of the pressure drop against the analytical solution provided by the Ergun equation.

CASE III
ERGUN TEST CASE – FLUIDIZATION

Fluid flow through a particle bed – the Ergun equation describes the resulting pressure drop in dependence of the fluid velocity.
When a certain minimal fluidization velocity is reached the particle bed will fluidize which will result in a constant pressure drop despite increasing fluid velocity.
Method: unresolved CFD-DEM – cfdemSolverPiso

Comparison of the pressure drop against the analytical solution provided by the Ergun equation, particle bed fluidizes at predicted minimal fluidization velocity Umf.

CASE IV
FLUIDIZED BED

An vertical air exerts a drag force
onto the particles and causes a fluidization of the bed. A good measure for quantifying the behavior is the consideration of the time-averaged void fraction (see results below).
Method: unresolved CFD-DEM – cfdemSolverPiso

Comparison of the time averaged void fraction of the bed at different heights – simulation results with CFDEM®coupling are in good accordance with experimental results from the literature.

CASE V
SPOUTED BED

A continuous air jet enters
through a hole in the bottom and causes a periodic motion of the particle bed. A good measure for the behavior of the spouted bed is the velocity at different heights (see results below.)
Method: unresolved CFD-DEM – cfdemSolverPiso

Comparison of the vertical velocity component at different heights – the simulation results obtained with CFDEM®coupling are in good accordance with experimental results.