Lagrangian Multiphase (LMP) to MMP sub-grid phase interaction
Reduces computational expense of hybrid multiphase simulations by transitioning small Lagrangian droplets/bubbles to MMP phases
Enables hybrid multiphase approach
including mixtures
Highly beneficial to applications such as
e-motor cooling where jets of oil break up into ballistic
droplets, which further break down into mixtures and even
foams
LMP breakup or other physics can lead to a large number of particles with low Stokes numbers
LMP is not an efficient or well suited
model for droplets/bubbles which are numerous, 10s microns in
size and carried with the continuous flow
LMP to MMP subgrid phase interaction
allows transition based on Stokes number, diameter and other user
criteria
LMP
diameter is passed to S-Gamma population balance model if
active
S-Gamma population balance model for MMP-LSI
Allows further transport of droplet (and/or bubble) sizes in MMP coming from LMP (or other sources) in the presence of free surfaces
Original S-Gamma model was only valid for
continuous dispersed flows
New approach allows phase inversion
through a free surface from a dispersed droplet phase S-Gamma
population below the free surface to a dispersed bubble phase
S-Gamma population above (if both active)
Mirrors implementation for EMP-LSI
Allows breakup and coalescence modeling at
sub-grid scale alongside resolved structures
Key to
predicting correct droplet and bubble sizes and transport of
phases
Includes model for bubble entrainment at
free surfaces
LMP impingement into MMP-LSI free
surfaces
Allows LMP
droplets to impinge into existing bodies of fluid
Mirrors
existing capability between LMP and VOF
Applies
when LMP droplets pass into region of high volume fraction of
corresponding continuous phase
Ensures most
appropriate model used locally
Avoids
tracking LMP droplets in continuous MMP phase of the same
substance
Typically LMP
impingement is sub-grid, but cell clustering can be used if impingement
effects are to be resolved
Volume of Fluid (VOF)
VOF wave model:
Turbulence vorticity limiter
Improves the
accuracy of wave propagation in marine simulations
Reduces
unphysical turbulence production that can develop around free
surfaces after several wavelengths and associated dissipation of
waves
Available when VOF
wave model selected
Available for:
Standard
and Realizable k-ε models
Standard
and SST k-ω models
Free surface quality
indicator field function and report
Allows easy
assessment of the quality of free surface capture in VOF
simulations
Free Surface
Quality Indicator field function has 3 possible values:
0 - No
interface
1 -
Smeared interface
2 - Sharp
interface
Corresponding
report, Free Surface Quality, can be used to determine the
average interface sharpness throughout selected regions
Report
returns ratio of sharp interface cells to all interface cells
(sharp and smeared)
An
interface that is sharp everywhere will return 1
Can be
used to trigger Volume Fraction Reinitialization
Eulerian Multiphase (EMP)
S-Gamma: Performance
improvements and reduction of default quadratures
Fewer quadrature
points needed to achieve consistent results independent of quadrature
point number
More
efficient distribution requires fewer points and less trial and
error
Reduced
computational expense and memory requirements
Default number of
quadratures reduced to 5 (from 8)
Typically 5
produces a good fit
Applies to both EMP
and MMP
Wall boiling: Li
nucleation site density model
Predicts more
accurate values for high levels of wall superheat compared to existing
models such as Hibiki-Ishii and Lemmert-Chawla
Less need
for limitation of nucleation site density
Improved
convergence compared to existing models
Normalized Phase Mass
Conservation Error and Iterations per Time Step reports
Reduce time to
solution whilst ensuring good convergence by using these reports to
drive stopping criteria
Provides
alternative to adaptive timestep approach using adaptive number
of inner iterations
Two new reports
are provided:
Normalized
Phase Mass Conservation Error
Can be used as basis for inner iteration stopping
criteria
Iterations
per Time Step
Can be used to monitor resultant inner iterations
Fluid Film
Habchi boiling
model
Improved accuracy for modeling boiling in Fluid Film beyond
critical heat flux
Includes Leidenfrost effect resulting in longer
(more physical) film residence times beyond transition compared
to existing model
Two options for Fluid Film boiling are now available
Habchi (new model)
Rohsenow (pre-existing model)
Lagrangian Multiphase (LMP)
Transfer model from free-stream to
wall-bound phase D4715
The benefits of
wall-bond modeling are now available to a larger set of water-management
cases with both free-stream and wall-bound representations of
droplets
New options and
models enable the transition to the wall-bound phase
Lagrangian-Lagrangian Phase Interaction
Deposition
model
Transfer
to Wall-Bound Phase mode in the Boundary Conditions menu
Parcel
Transfer Injector for free stream to wall-bound phase
automatically created with activating Deposition model
Cyclic Injector Specification for Table injectors
Simplified workflow for converting the
outcome of VOF simulation into the input of faster LMP simulation using
the new Cyclic Injector Specification option
VOF
simulation or experimental data provides droplet initialization
data for one rotation or cycle
LMP
simulation reuses the same data in a cyclic manner
Applications: E-motor cooling; fuel,
paint, and agricultural sprays with cyclic output from nozzles
Postprocessing
injectors using Solution History
Advanced
post-processing of the initial state of injected particles by selecting
the injector as an input to the Solution History
Useful for
comparing the state of particles at different locations with the
state of particles generated by the injectors
Discrete Element Method (DEM)
Particle Agglomeration model
Accurate modeling of particle
agglomeration and deposition via the upgraded Parallel bonds contact
model
Two bond
formation options
Time Window, existed previously
User Defined, the bond forms only at specific local
conditions
Bonding
material can differ from particle material, two options for Bond
Stiffness
Particle Material Based, existed previously
User Defined, for a wide range of granulation
applications
Parallel
bonds renamed to Particle Agglomeration
Bonding
between particles and boundaries enabled
Contact Time field
function
Access additional
useful information about particle state via new field function
The Contact Time field
function returns time elapsed since the beginning of the
particle-particle or particle-wall contact
Available for all
particle types and shapes
Improved realism when modeling
contact time-dependent physics such as particle agglomeration
Injection Table option for Particle
Orientation
Ability to transfer
the particle state from one simulation file to another when particles
are non-spherical
New
Injection Table option for Particle Orientation method
Reads the three table columns with values of angles
that define particle orientation
Improved control
over the initial orientation of non-spherical particles
Smoothed-Particle Hydrodynamics (SPH)
Inlet boundary conditions
Enable analysis of applications with liquid injections with the support of inlet
boundary conditions
Velocity Inlet and Mass Flow Inlet
Compatible with Constant, Time evolution, and Field
Functions
Rotating and static inlet boundaries
Target applications: vehicle water runoff,
powertrain lubrication by injection
Reports for removed particles
Enhanced monitoring tools to assess the simulation convergence through new reports
for removed particles
Report for Particle Remediation Removed
Particles
Position-Based and Velocity-Based
Enhanced Moment report
Increased accuracy for the Moment report
No dependency on the surface mesh resolution
Visualization of Velocity on solid boundaries
Faster simulation analysis with the visualization of
velocity vector and scalar field on solid boundaries
Wall velocity depends on the solid boundaries type
(slip or no-slip walls)
