As is my custom, whenever a new version of Simcenter STAR-CCM+ is released, I go over and summarize the most important news for multiphase simulations. And the release of Simcenter STAR-CCM+ 2510 will not be an exception to this rule. I will go over here what we at Volupe find to be the most impactful changes and editions to multiphase simulations.
Generalized phase replacement model
The generalized phase replacement model is an improvement to the phase replacement model available in VOF-simulation. Where the old version was often used to remove numerical ventilation in marine simulations, by allowing the primary phase to be replaced by the secondary phase, it is now possible to go also the other way. What this model does is replace one phase with another phase based on a certain user defined criterion. The advantage of this model is that it can allow you to remove spurious flow features from under resolution, especially for cases where you know that improved resolution would not provide any engineering value. At the same time, you can remove physical and correct flow features, that might lie outside your area of interest, that also do not provide any engineering value to your simulation. This model is now available for both VOF and MMP.
Particle Rotation model for solid particles
Lagrangian particle simulations have previously had its largest strength in liquid droplet simulations, like fuel-spray, and spray-drying type simulations. Siemens have however put a strategic focus on expanding the solid particle capability for LMP. This now introduces the feature that allows us to resolve the particles’ rotational degree of freedom for solid LMP-particles. This is important because without it, particle paths can be inaccurate. The new particle rotation model unlocks drag Torque, spin lift force, and user defined drag torque, which subsequently allows for more precise modelling. It also adjusts particle-wall rebound calculations to take rotational effects into account. This means that we now have an overlap in LMP and DEM capability, and seeing as LMP is far cheaper computationally, it becomes the obvious choice where particle-particle interactions can be ignored. The video shows the difference in including rotational effects and not doing so. The deposit shape and location is highly impacted by accounting for rotation.
Wall-bound droplet coalescence model
In this version, we see the introduction of a collision model specifically for wall-bound Lagrangian phases. In many applications it is important to be able to capture the complex dynamic of droplets sliding, interacting, and merging. This new feature improves the accuracy of predicting both the spatial distribution and the size distribution of liquid droplets as they slide across a surface. The model is based on the NTC collision model framework but has here been adapted for wall-bound particles. It models coalescence, meaning that when droplets collide on a surface, they will merge and form larger droplets. Compared with the free-stream NTC collision model, this means that there is only a coalescence outcome in the collision map. The animation below shows the same example simulated without (left) and with (right) coalescence. We can see that the inclusion of coalescence allows for larger droplets to accelerate and sweep up the smaller, stationary droplets. This interaction results in a more realistic and accurate distribution of droplets across the surface.
Template DEM phase interactions
It is now possible to template DEM phase interactions. This means that you can create a set of templated phase interactions and assign all phase interactions to the template. Assume you have several DEM-phases, this means that you will need interactions for all phases towards boundary interactions as well as interactions between all DEM-phases towards all other DEM phases. With many different phases and/or several different boundary-interaction types, this will help you reduce the number of interaction setups.
DEM compatibility with Fluid Film
In version 2510, there now exists a basic compatibility between DEM and Fluid film. This includes the option to select DEM mode for contact with a Fluid Film boundary, and that makes the most standard particle-wall contact modes available. So, far this excludes the conduction heat transfer, but that is planned for future release. The animation shows this application for tablet coating in a rotating drum.
User-Defined Flexible Fiber model
We now have access to a dedicated shape editor. This allows us to create user-defined flexible fibers. The development of this capability comes after community ideas. Input for segment can be provided manually or via table, similar to the shape editor for particle clumps or composite particles. This also comes with the option of “has stored compression energy”, that will when activated relax the fibers to straight rods in the absence of external forces.
SPH-solver improvements
A few new features are also available for the SPH-solver. First, it is now possible to run SPH with particle refinement. You can refine based on shapes locally, and outside of your shape refinement criteria particles will coarsen. Particle refinement allows for 10 levels of refinement and is compatible with all models accessible with SPH (CPU and GPU), but it is only available with the boundary Integral Method for wall representation.
Secondly, the SPH-solver is now compatible with mesh-free multibody motion. Since you are no longer limited to rotation, this opens up for several applications previously not accessible. You can model contact between different solid bodies and the motion from the SPH fluid forces.
It is also possible to run your SPH-simulations with an outlet boundary condition, both a pressure outlet definition and a mass flow rate outlet. You can also link two simulations and set up a 1-way FSI-simulation. You can model the effect the fluid flow (SPH) has on a solid (but not the other way around).
I hope this has been an interesting read and that you can utilize some or several of these features in your simulations. Reach out with any questions to support@volupe.com.
Author
Robin Victor
support@volupe.com