Heat transfer

Version 7 introduces a new solver for conjugate heat transfer between fluids and solids:

• It uses the finite volume method for the solid part of the simulation, and its standard particle-based MPS method to calculate heat transfer on the fluid side.
• The new finite volume method does not require the meshing of the solid bodies.
• Particleworks automatically generates Voxels to calculate heat conduction in solid bodies. The dimension of a Voxel is equal to the spacing set by the user for the definitions of the wall boundary condition.
• The Voxel dimensions can be different from the particle size.

This method eliminates the need to generate solid particles to solve heat conduction.
For applications with very different time scales for fluids and solids and where transient thermal phenomena are not of interest, fluid-solid heat transfer and temperature are predicted by decoupling the simulation of transient fluid from the thermal conduction analysis:

• Particleworks predicts the fluid flow and the heat transfer coefficient (HTC) on the solid walls and maps the HTC distribution onto a fixed element analysis (FEA) model.
• Under steady-state conditions, the temperature distribution of the solid can be calculated in a few minutes for heat conduction analysis.
• Particleworks’ primary role here is accurate HTC map prediction, and version 7 includes a user-defined HTC correlation:
  - the user can define the HTC correlation based on local flow conditions,
  - the HTC prediction can adapt to the flow characteristics even in complex systems, such as an electric motor, where the flow behaves differently in different areas (flow parallel to the wall, impinging jet, pipe flow or other, depending on the region of the electric motor).

Airflow modeling and two-phase flow

Particleworks 7 has a new embedded airflow solver that is fully coupled with the liquid MPS solver:

• The air solver is a finite volume CFD based on a Cartesian grid
• Mesh generation is not required
• Particleworks automatically creates a Cartesian grid based on the wall spacing definition
• Coupling the airflow solver with the liquid MPS solver allows the gas and liquid phases to be simulated simultaneously, allowing for the reciprocal influence of the two fluids (multi-phase calculation with momentum transfer).

Graphical user interface

Particleworks 7 introduces a viewer API and a Python API:

• the user can script and automate the entire process from project creation, model definition, physical properties, and numerical set-up, to solution and post-processing.
• Automation of the simulation process via C++ or Python drastically reduces manual effort and time for repetitive operations, e.g. for comparing multiple designs or the operating conditions of the same system.
• It also paves the way for process integration and design optimization to be applied to Particleworks models.

Some seemingly minor, but actually highly useful new features also available in the new user interface, include:

• The ability to compare scenes to detect the configuration differences between different simulations
• Copy and paste objects and define periodic movements for faster set-up.
• a new task manager with improved usability
• For solution monitoring, the user can define live plots of physical and numerical quantities that are displayed in the interface and automatically updated during the solution
• This makes it possible, for example, to monitor the behavior and stability of the solution and to obtain an immediate idea of trends in physical quantities such as torque or thermal balance.
• The multi-view feature allows multiple scenes to be displayed in a single window. The user can:
  - display different views of the same simulation at the same time,
  - show different variables for different views,
  - visualize the results of two or more projects or scenes to compare them

Pairing with third-party software

Particleworks 7 can dynamically interact and co-simulate with a wide range of third-party software via functional mock-up interface. The list of tools that support FMI is available on the FMI standard web-site

One of the most interesting pairings and co-simulations is with Adams, a well-known multi-body tool:

• An important application is wading simulation.
• A Particleworks-Adams co-simulation can account for the dynamic effects of the vehicle and the vehicle-water interaction at the same time.
• Co-simulation allows you to calculate vehicle motion and water splashing simultaneously, taking into account the effect of water forces on vehicle dynamics.

A special case is the coupling of Particleworks with Ansys Mechanical and Ansys Fluent.

• A dedicated Particleworks-for-Ansys interface was already available for version 6
• Its development has produced a new version compatible with Particleworks 7 with new features.
• Particleworks-for-Ansys allows the user to automatically transfer data from Particleworks to Ansys Mechanical for constant and transient stress and thermal analysis
• Ansys Fluent can transfer constant and transient airflow fields to Particleworks.
• This is an alternative way to measure the effect of airflow on liquids flows.

Visualization

Realistic rendering that allows the user to “enter and view the results from the inside” helps to understand and communicate the results of a simulation. Particleworks 7 has a dedicated plugin that converts its results into a graphical format, editable with computer graphic tools like Blender, Unity or others.