What's New

View new features for AcuSolve 2025.1.

Altair AcuSolve 2025.1 Release Notes

Highlights

  • Chemical Reaction for AcuSolve-EDEM coupling blast furnace applications.
  • Immersed boundary surface (beta)
  • Battery gas venting
  • Thermal topology optimization
  • AcuSolve-Flux two-way coupling

New Features

EDEM coupling with chemical reaction for Blast furnace application
The AcuSolve-EDEM coupling has been extended to support chemical reactions, primarily targeting blast furnaces in the steel manufacturing industry. This chemical reaction model includes both homogeneous and heterogeneous reactions in the bidirectional coupling, which are modeled alongside momentum and energy exchanges. This model can be utilized for coal gasification and combustion in fluidized reactions, as well as iron ore reduction in blast furnaces, predicting ore reduction using either carbon (coke particles) and/or hydrogen processes.
Immersed boundary surface (beta): Enhancing mesh flexibility
While AcuSolve does not rely on mesh quality, creating water-tight meshes can be time-consuming for you. Additionally, certain corner cases, such as overlapping blade applications in mower scenarios, cannot be handled by water-tight meshes. To address these challenges, the AcuSolve team has developed the immersed boundary surface and introduced this feature as a beta, as further fine-tuning is necessary. The immersed boundary surface provides greater flexibility in mesh generation, allowing you to swap parts for design optimization and significantly reduce pre-processing time, as it does not require clean CAD models. This beta feature currently supports flow, turbulence with the SA turbulence model, complex mesh motion, and EDEM coupling. However, heat transfer and radiation are not supported in this version. In SimLab, the immersed wall icon is available when flow with particle solution is selected.
Battery gas venting modeling
Lithium-ion batteries are equipped with vents or burst discs designed to release gases during thermal runaway. These vents serve as a critical safety function by preventing excessive pressure buildup, which could otherwise lead to cell rupture or explosion. AcuSolve’s thermal runaway battery solution has been enhanced with two models to simulate gas venting in lithium-ion batteries:
  • Experimental Gas Venting Data Model- This model relies on experimentally measured venting parameters, such as the mass flow rate of vented gases and vent gas temperature. Venting is triggered based on cell temperature.
  • Pressure-Reaction Model – This model simulates gas venting by directly calculating gas accumulation, pressure buildup, and subsequent venting. The venting is triggered when internal pressure exceeds a critical threshold. This method requires gas composition analysis, such as Gas Chromatography-Mass Spectrometry (GC-MS) analysis performed post-ARC testing.
Thermal topology optimization
Topology optimization has been extended to include thermal optimization, enhancing the design of heat sinks, cooling jackets, and cooling plates. This feature optimizes temperature changes from inlets to outlets, ensuring the best thermal performance while controlling fluid losses. A major benefit is the elimination of hot spots, leading to even temperature distribution across devices. You can define objectives to maximize temperature from inlets to outlets while constraining mechanical fluid losses. The process uses filtering equations to set minimum design sizes, avoiding overly small features in the computed geometry. Among the turbulence models available from AcuSolve, the SA turbulence model now supports topology optimization for high Reynolds number flows. The topology is computed as a design field, which can be visualized at any iteration during the simulation. At the final iteration, a level-set surface is computed based on a user-defined length scale, providing smoother geometry for downstream applications. You can remesh this computed geometry with a body-fitted mesh to validate device performance. SimLab does not support this feature in time for the release. While waiting for the SimLab implementation, a Python script can be used to convert an input file with basic flow settings to a topology optimization input file.
AcuSolve-Flux Two-Way Coupling
Engineers developing electric machines can now accurately predict thermal behavior under electromagnetic influences, enabling enhanced cooling strategies and performance evaluation. This is achieved through the two-way bi-directional coupling of AcuSolve and Flux via the Kratos framework. This coupling is particularly valuable for improving performance of electrical machines, such as electric motors and induction heating devices. The Kratos framework facilitates seamless data sharing between AcuSolve and Flux, accommodating different mesh types with a reliable mesh mapper. It supports 3D AcuSolve with 2D Flux coupling. The AcuSolve-Flux two-way coupling and the Kratos library are integrated within SimLab, which operates on the Windows platform.

Enhancements

Wet Particle Initialization
A new parameter, edem_initial_liquid_mass_ratio, is introduced to set the initial fraction of liquid mass applied to particles for wet particle modeling in AcuSolve-EDEM bi-directional simulations. This enhancement streamlines the workflow of wet particle modeling in industries that handle wet granular materials, such as asphalt production manufacturing using a rotating drum dryer or pharmaceutical industry using a pill dryer.
Non-Zero Starting Time Support for EDEM
A new parameter, edem_initial_time under AUTO_SOLUTION_STRATEGY, enables setting a non-zero initial time for starting or restarting the EDEM solver in coupled simulations. You can now restart simulations from an arbitrary point in time, reducing redundant computations and allowing more flexible case setups.
AcuTrans File name Using User-Defined Names
AcuTrans now supports user-defined names for file names instead of numerical IDs in post-processing.
PowerShell Script for AcuSolve Windows Environment
AcuSolve’s Windows distribution now includes a PowerShell script (acusim.ps1) for directly sourcing the AcuSolve environment in a PowerShell terminal. This allows you to:
  • Execute AcuSolve commands directly in PowerShell.
  • Run custom PowerShell scripts with AcuSolve environment settings pre-loaded.
Windows users can now work with AcuSolve more efficiently without needing additional setup, streamlining script execution and automation.

Resolved Issues

  • Fixed an issue where the porosity_model with cylindrical porosity and radial flow direction did not function correctly.
  • The diffusivity equation (2) under DIFFUSIVITY_MODEL was updated to reflect the density-weighted diffusivity definition.
  • The acuFWH and acuRunFwh sections were removed from the Program Reference Manual, as AcuSolve is no longer positioning for the acoustic applications.

Altair AcuSolve 2025 Release Notes

Highlights

  • Porous media support for AcuSolve-EDEM coupling.
  • Support for multiple field interaction models in AcuSolve-EDEM coupling with multi-drag model selection.

New Features

Porous media support for AcuSolve-EDEM coupling
Modeling a screen or a filter using the AcuSolve-EDEM coupling approach presents a challenge due to the extremely high mesh count required for AcuSolve. Simplification is necessary to reduce computational time. In this scenario, the pressure drop in the flow is modeled using a porous medium, while particle interaction with the screen is handled in EDEM. The porous_medium_region parameter in the ELEMENT_SET can be used to activate the porous medium based on the physical velocity porous approach in one of the carrier field elements.
Multiple field interaction model support for EDEM coupling multi drag model selection
In AcuSolve-EDEM coupling, you may need to select different drag models for particles based on their size and shape. To achieve this, each drag model must be defined using the dedicated FIELD_INTERACTION_MODEL. To support this, a new parameter, edem_particles_names, is introduced which retrieves the list of EDEM particles referenced in the FIELD_INTERACTION_MODEL.
Coarse graining for EDEM coupling
In AcuSolve-EDEM coupling, the number of fine particles significantly impacts simulation runtime. To reduce computational cost, groups of fine particles can be represented by larger particles, known as "grains," thereby decreasing the total particle count in the simulation. The edem_coarse_grain_factor is used to adjust the coupling forces within this coarse-grain system. This factor ensures that the scaled dynamics of the grains accurately represent those of the original fine particles. The coarse grain factor is defined as the ratio of the grain radius to that of an individual original particle.
Non-zero starting time support
A new parameter, initial_time, under AUTO_SOLUTION_STRATEGY now allows you to set a non-zero starting time. While available for all standard AcuSolve simulations, this feature is especially useful for AcuSolve-EDEM coupling simulations, enabling AcuSolve to start at a specified non-zero time after initial particles are generated within EDEM.

Enhancements

Enhancements to auto_wall_surface and Improved Result Consistency
auto_wall_surface_output was revisited to streamline and enhance the heat balance process by eliminating duplicate surfaces. This improvement ensures complete and unique auto_wall surfaces, facilitating accurate heat balance calculations. Additionally, by changing the solver's default setting of exchange_sort_receive better consistency was achieved in results across and run-to-run variations.
Eliminating particle inputs for AcuSolve-EDEM coupling
In previous versions, AcuSolve-EDEM coupling for non-spherical particles required input parameters for sphericity, aspect ratio, and volume using edem_particles_sphericity_values and edem_particles_aspect_ratio_values. As of this version, these parameter requirements have been eliminated.
Floating monitor surface extended to mesh motion
Starting in version 2023, the floating surface output feature enables output data generation without requiring mesh construction around the desired surface. This version further extends this capability to domains with applied mesh motion.
Time-base curve-fit option for GRAVITY interpolation
In the GRAVITY command, a new curve fit variable of time is introduced, enabling you to easily interpolate user data over time without needing to rely on UDFs.
acuOdb enhancements
You can now export AcuSolve data in Abaqus (.odb) format with enhanced options: You can specify a particular element set using the ‘-outs’ option and apply model scaling with the ‘-scale’ parameter.
Documentation Additions
Training manual
  • The thermal-electric battery simulation setup and guidelines in the Solver Feature Guidelines have been updated, summarizing the required battery module input parameters and adding a new section detailing ECM parameter specifications for the battery model.
  • A new section on submitting AcuSolve jobs on Linux servers has been added to the Solver Feature Guidelines.
  • Details about the Eulerian multiphase models and turbulence models are now available under the AcuSolve Solver Features section.
SimLab-based Tutorial Updates
Two (2) tutorials for the SimLab CFD user interface have been updated. The updated tutorials are:
  • ACU-T: 3513/SL-2176 ARC-based Thermal Runaway: 1S1P Module
  • ACU-T: 7202/SL-2502: CFD Topology Optimization of Multiple Flow Paths

Resolved Issues

  • Users reported that acuSig for clean-stop was not functioning properly, with issues depending on the Linux version and hardware. This has been resolved in the 2025 version.