Fluid Flow Modeling
Set or Modify Fluid Flow Properties
In Rocky DEM, there are four unique methods for simulating the interaction between particles and the surrounding fluids (air, water, dust, etc.), known more commonly as Computational Fluid Dynamics (CFD).
Lattice Boltzmann Air Flow Method
The first method is accomplished by enabling Rocky to calculate how particle flow and the boundaries that contain those particles affect the air that comes into contact with them.
This method uses the Lattice Boltzmann Method (LBM) for its calculations and is useful for simulating how much dust a transfer chute design would generate, for example.
In this method, the air flow does not affect the movement of the particles; only the particles and the boundaries affect the air flow.
Constant One Way Method
The first of the two One Way methods, the Constant One Way method, is useful in cases where you have a known, unchanging fluid field and want to understand how it impacts the flow of particles without having to use a separate CFD program.
You can set a constant value for density, velocity, viscosity (and thermal properties if thermal is being solved), and Rocky DEM will use those values to simulate the fluid field.
Ansys Fluent One Way Steady State Method
The second of the two One Way methods is accomplished by a one-way steady-state coupling with Ansys Fluent. In this method, a CFD simulation done within Ansys Fluent calculates the velocity and pressure fields generated by the fluid as it flows through the equipment being studied.
At the end of a simulation, or once steady state has reached the flow field, that data is then exported out of Ansys Fluent and imported into Rocky DEM, where Rocky DEM then calculates how the fluid flow would affect the particle flow.
The Ansys Fluent One Way Steady State method is particularly useful for simulating the effect of water on the movement of particles through a pipe, for example. Or, for simulating the transport of particles with different densities by water in a slurry-like flow.
In the Ansys Fluent One Way Steady State method, the particles do not affect the fluid flow; the fluid flow affects the movement of the particles.
Ansys Fluent Two Way Method
The Ansys Fluent Two Way method, is particularly useful for simulating complex phenomena such as pneumatic conveying, granular drying, slurry flow inside grinding mills, or even chemical reactions between particles and fluids.
In the Ansys Fluent Two Way method, the particles are part of the fluid flow and will affect it in a two-way interaction: particles are affected by other particles and the fluid around it while the fluid flow is also affected by the particle pressure.