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Factories
In EDEM, there are two types of particle factory: dynamic and static. Dynamic factories produce a set number of particles at a set rate. Static factories produce a set number of particles in a single timestep. When setting the particle creation rate, remember to consider particle size and space available since setting a factory to produce too many particles for the available space will slow down your simulation.
Particle Properties
Ensure you calculate your particle properties before starting a simulation, as incorrect properties can produce non-physical behavior.
To speed up your simulation, try reducing the shear modulus of your particles. To determine optimum values, compare a simulation with experimental results or compare the results of one DEM simulation with another.
The Rayleigh timestep is calculated from the particle size defined in the Creator. If your simulation uses a a random, normal, or lognormal size distribution, re-calculate the Rayleigh timestep from the smallest particle in the distribution.
Creator
You may not need to define complex object geometries for your simulation: you only need to include geometries that influence the particle dynamics.
If using a series of complicated rotations (for example, when simulating a bucket motion), use the Move with Body option and define your point of rotation at the initial position of the geometry. This reduces the number of calculations required as EDEM will not need to calculate the position of the rotation point once the geometry begins moving.
Simulator
Set the time-step to suit your simulation. For example, a simulation with fast moving particles may require a timestep lower than the standard 40% of Rayleigh.
Depending on your system resources, adjust the number of grid cells in the simulation. Typically, 100,000 grid cells require around 1 Gb of RAM. The optimum grid cell size is 2Rmin.
To increase simulation speed:
- Disable the Auto-update option
- Reduce the particle display detail
- Set the geometry display to Mesh
- Close the solve report
If you are low on disk space, try reducing the simulation`s write-out period. Take care not to reduce this too much, as a low write-out period may not capture all the required information.
Analyst
If you need particle collision data, remember to specify this before running a simulation.
EDEM features a range of visual and graphical tools to help analyze your results. You can also export your simulation data from EDEM and read it into other 3rd party applications for analysis.
Before capturing images, set the background and particle color to suit your needs.
EDEM-CFD Coupling Module for FLUENT
Of EDEM`s available coupling methods, Lagrangian is faster than Eulerian, as Eulerian calculates volume as well as momentum transfer. Use the Lagrangian coupling method when your simulations have a dilute solid phase.
The FLUENT timestep can be 10 to 100 times larger than the EDEM timestep. A particle should remain within a FLUENT mesh cell for three fluent timesteps.
Ideally the FLUENT mesh cells should have a volume equal to or larger than the largest particle in the simulation. All particles must be located within a fluent mesh cell: the simulation will slow down when there are particles or particle sample points outside the FLUENT domain.
All simulations have to be initialized after they are coupled.
The EDEM License Server
To restart an MS Windows EDEM license server:
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From the Start menu, open the Control Panel.
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Click Administrative Tools > Services.
- Scroll through the list to find and select the Sentinel LM service. Right-click then select Restart from the pop-up menu.
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