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FLOW-3D Cast v4.1 aims to further streamline metal casting engineers’ simulation workflows by enabling them to more quickly set up simulations, avoid common errors, identify and enter missing data, and analyze simulation results faster and more effectively.
Active Simulation Control
Active Simulation Control allows simulation parameters to be automatically changed during run-time based on user-defined conditions at history probes. Simulated variables recorded by history probes can be used to control the behavior of time-dependent objects, such as mesh boundary conditions, mass sources and GMO components. For example, a shot plunger in an HPDC simulation can be transitioned to a fast shot when metal reaches probes located in gates and also increase data output frequency to capture more flow details.
An HPDC simulation where fast shot is automatically triggered when the fluid reaches the gates. The triggering process is automated through the new Active Simulation Control feature. The plunger motion during the slow shot has been calculated using the Barkhudarov method1 to minimize the amount of air entrained into the melt in the shot sleeve. This results in much higher quality castings and reduced scrap rates.
Batch Postprocessing & Report Generation
Batch post-processing and report generation have been developed hand-in-hand to save users significant time when it comes to visualizing, analyzing and communicating the results of their simulations. With batch post-processing, users can define a series of animations, scenarios, plots, and text data that will be automatically generated when the simulation completes. The graphic requests are defined in FLOW-3D Cast which runs FlowSight in the background. Graphic requests can also use context files to create the desired output. Once batch post-processing has completed, the user can create a fully-featured report in HTML5 format that can be easily sent to his or her manager, associates, colleagues, or clients. Images and videos can be embedded in the report, and the user retains full control over the formatting of text, captions, and references.
Metal Casting Models
Squeeze Pin Model
Squeeze pins can now be simulated to model the behavior of the real die casting machines, where they are used to compensate for metal shrinkage during solidification in hard-to-feed areas of the casting. Squeeze pins can be created using STL files or interactively by adding a cylindrical squeeze pin on a selected surface.
Intensification Pressure Model
A new plunger-type geometry has been added. Intensification pressure can be specified to remove macro-shrinkage and micro-porosity.
Thermal Die Cycling model
The thermal die cycling model has been enhanced by the addition of two new stages: the ejection stage, when the die is open but the part is still attached to the ejector die, and the preparation stage, when the die is closed just before the filling. In addition, the thermal die cycling solver has been optimized to deliver a fully-converged thermal solution during all thermal die cycles instead of targeting the solution towards the last cycle. This is achieved at no loss to performance.
Valves and Vents
External pressure and temperature at valves and vents can now be defined as a tabular function of time, allowing users to define a more realistic behavior of these components of the die casting process during filling. The valve/vent pressure and temperature can also be controlled by probes placed inside the cavity, which is useful during the process design stage.
The PQ2 diagram allows users to better approximate the shot machine capability. The new feature is especially useful during the die casting design stage, when it is not known what gate velocities a given shot machine can achieve.
Cooling channels can now be controlled by the total amount of heat removed or added by each cooling channel to the die.
Air Entrainment Model
A new option has been added to the air entrainment model to take into account the compressibility of the entrained air. Air compressibility is important in flows with significant variation of fluid pressure, for example, in the high-pressure die casting filling process
The cavitation model has been enhanced to better represent the behavior of cavitating fluid over a wider range of flow conditions. A new option for cavitation nucleation, based on empirical relations, complements the existing constant rate approach. A new passive gas model option has been added that tracks the cavitating gas in the fluid but does not open bubbles, thereby reducing computational time and meshing requirements.
Two-fluid Phase Change Model
The two-fluid phase change model has been extended to include super-cooling.. It is implemented by defining a constant super-cooling temperature and allowing the gas temperature to descend below the saturation point before condensation takes place.
Simulation Results and Analysis
Simulation Results File Editor
A utility to edit FLOW-3D Cast v4.1 results files allowing users to merge results files and remove edits.
Linking flsgrf.* files
Restart simulation results files (flsgrf.*) can be linked to the results files from restart source simulation to display the results in a single, continuous animation in FlowSight.
Fluid/wall Contact Time
A new spatial quantity has been added to the solution output that stores the time that metal spent in contact with each geometric component, as well as the time spent by each component with metal.
Performance and Usability
Calculators to help estimate heat transfer coefficients, the thermal penetration depth, valve loss coefficients, the fluid depth in the shot sleeve, and the plunger speed are now available directly in the Model Setup dialogs. They are also accessible from the Utilities menu.
Thermal Die Cycling
The setup has been greatly simplified through the introduction of predefined thermal segments and the inclusion of a heat transfer database.
GMRES Pressure Solver
The speed of the GMRES pressure solver has been improved by up to a factor of two by optimization of data structures used in the solver. The gain in performance comes at a modest increase in memory usage of less than 20%.
The sampling volume tool has significantly expanded by allowing the definition of sampling volumes using an STL geometry. The list of output quantities calculated for each sampling volume has been expanded to include all the same quantities computed for the whole computational domain, such as fluid volume, min/max temperatures and particle counts.
Performance of the structural analysis model has been enhanced through improved parallelization and optimization of the solver for simulations with partial coupling.
Workspaces can now be imported from previous installations of FLOW-3D. Workspaces and user selected simulations can be copied
Expanded Simulation Pre-check
The simulation pre-check now includes the preprocessor checks and links an issue to where the problem is occurring.
The depth-peeling option now gives better representations of transparent geometries and is 10x faster than v4.0.
There are new, interactive creation tools for baffles, history probes, void/fluid pointers, valves, mass-momentum sources, and squeeze pins. Additionally, the interactive tools for probing and clipping are improved.
All objects (e.g., mesh blocks) can now be enabled/disabled.
Estimated Remaining Simulation Time
The estimated remaining simulation time has been added to the short-print output to the solver message file.
Ability to reverse signs on tabular data that allow negative values by right clicking on selected data. Ability to right-click and save to .csv or copy to an external file.
1 23-10 Michael R. Barkhudarov, Minimizing Air Entrainment, The Canadian Die Caster, June 2010