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Flownex SE 2026 Release 1

Flownex 2026 R1 is here, bringing powerful new capabilities to the 1D simulation environment.

This release introduces a focused set of major and minor improvements designed to make simulation workflows more robust, connected and user-friendly. Key updates include Ansys Mechanical integration, a reworked Flownex Workbench integration, improved Excel functionality, enhanced Revit Builder capability, and extended support for Python-driven workflows.

Together, these updates give engineers more flexibility, better integration with existing tools, and a smoother path from model development to analysis and decision-making.

Flownex SE 2026 Release 1

Flownex 2026 R1 is here, bringing powerful new capabilities to the 1D simulation environment.

This release introduces a focused set of major and minor improvements designed to make simulation workflows more robust, connected and user-friendly. Key updates include Ansys Mechanical integration, a reworked Flownex Workbench integration, improved Excel functionality, enhanced Revit Builder capability, and extended support for Python-driven workflows.

Together, these updates give engineers more flexibility, better integration with existing tools, and a smoother path from model development to analysis and decision-making.

major enhancements

The complete Release Notes containing detailed descriptions of the enhancements in the Flownex SE 2026 R1 version 9.1.0 are available under the Help ribbon in the latest Flownex SE release.

ansys mechanical integration

Network Builder Enhancements for 3D Models

CAD entity selection options for rotating components were enhanced to allow the extraction of appropriate measurements from full 3D CAD models.

Due to Ansys Mechanical platform speed enhancements, using Ansys version 2025 R2 or later will result in a faster user interface when using many wall tracing components (Rotating Cavity walls, Bolts and Labyrinth seals).

Rotating Cavity Walls

Cavity wall profiles can now be extracted from a set of faces. A user can also specify the angle of rotation (also called the Azimuthal Angle or Clock Position) at which the wall profile must be extracted, as shown in Figure 1 to avoid unwanted wall features such as holes or bolts.

Figure 1: Specifying the Profile Extraction Angle.

In Figure 2 as an example, the extraction of a complex profile for a rotating cavity wall is demonstrated.

Figure 2: Extraction of a Complex Profile for a Rotating Cavity Wall.
Rotating Cavity Bolts

Bolt areas can now be extracted from bolt surface selections for various bolt shapes, as shown in Figure 3.

Figure 3: Extraction of Bolt Areas from Bolt Surface Selections.

Bolts were moved from the Cavity inputs section into separate sub-components. The bolts are not limited to three rows anymore. If bolts were specified in previous versions, the bolts will be converted to Bolt components. To add a new Bolt component, right click on a Cavity and select “Add Bolt”, as shown in Figure 4.

Figure 4: Adding New Bolts.
Figure 5: Bolts Added to a Cavity.
Labyrinth Seal

When selecting two faces or edges, as shown in Figure 6, the appropriate directional data (axial or radial) will be extracted for each case. In the example below the axial pitch is extracted.

Figure 6: Selecting Two Faces or Edges.

In the below example, two edges are on a different axial offset and the correct clearance result in the radial direction will be extracted.

Figure 7: Appropriate Directional Data Extraction.

A seal diameter can be specified by selecting one edge or a face, as shown in Figure 8.

Figure 8: Selecting an Edge or a Face for the Specification of a Seal Diameter.
Restrictor
  • Options were added for outer and inner selections to calculate annular flow areas. 
  • A tailored entity selection mode has been added that enable selection of revolving annular gaps as shown in Figure 9. The annular area is calculated using Pappus’s centroid theorem.
Figure 9: Selection of a Revolving Annular Gap.
3D Surface Trace Caching

To speed up the user interface, the results for data extracted from face elements are cached and will be updated when related properties are changed, such as the face entity selection, profile extraction angle or the minimum wall interval.  To force a full re-calculation, the Rebuild Tracing menu item on the Flownex Network Builder can be used.

Figure 10: Rebuild Tracing Menu Item on the Flownex Network Builder.
Ansys Mechanical Flow Solver Coupling
Non-Axisymmetric Element Modelling

Non-axisymmetric loads can be applied in 2D axisymmetric models to represent features that are not supported by standard load definitions in Ansys Mechanical. This capability enables more accurate modelling of complex geometries, such as disks with radial holes shown in Figure 11, where conventional approaches may be insufficient.

Figure 11: Non-Axisymmetric Element Modelling.

To accurately represent non-axisymmetric features, the following key adjustments are applied:

  1. Volume Scaling – Accounts for the reduction in solid material due to the holes.
  2. Hole Wall Convection Addition and Scaling – Captures the additional inner heat transfer area between the fluid and the hole walls.
  3. Hole Opening Scaling – Reflects the reduction in available cavity wall heat transfer area due to hole openings.

These effects are introduced through custom loads that apply the appropriate scaling within the model. The ACT extension automatically calculates the required scaling factors based on Network Builder surface selections on the relevant components.

Workbench Integration

An enhancement has been made to embed a Flownex project within the Workbench project and link the project to the Mechanical model to set the project on the Network Builder and Flow Solver coupling tree objects in Mechanical.

Figure 12: Flownex Project Embedded in Workbench Project.

A project can now be updated (including parameterised geometry) from Workbench and multiple design points can be run with retained Flownex results for each design point.

Transient Actions from Mechanical

Time-dependent property variations can now be specified directly in Mechanical. Flownex Specific Properties and Global Parameters can be updated, with property step values aligned to the steps defined in the Mechanical Analysis Settings. This leverages Mechanical automatic time stepping to enhance solution stability during property updates.

Figure 13: Dynamic Temperature Boundary Conditions Specified in Mechanical.
Independent Time Step Size

In many cases, resolving swirl effects in Flownex requires smaller time steps than Mechanical, as fluid phenomena change more rapidly than the solid response. This can lead to unnecessarily small co-simulation time steps and increased solution times.

An enhancement has been made that introduces independent time stepping for Flownex and Mechanical. Flownex can operate with a defined maximum time step size, while data exchange occurs only at the Mechanical time steps, improving overall co-simulation efficiency without compromising solution accuracy.

Figure 14: Maximum Flow Solver Time Step Settings in Flownex.
Incremented Data Exchange for 3D Cavities

Discretized data exchange between Mechanical and Flownex is typically achieved using fluid couplings, where fluid lines are defined in Mechanical and assigned as named selections in Flownex. For 3D cavities, however, defining fluid lines in the direction of Flownex incrementation is not practical.

This release introduces support for incremented data exchange in 3D cavities, removing the need for fluid line definitions in such cases.

Figure 15: Incremented Data Exchange for 3D Cavities.
Components and properties
User Properties

An enhancement has been made for users to add additional properties available in Flownex that are not included in the list of properties of a component in Mechanical. These additional properties can be added by right clicking on a component and adding a new “User Property” as shown in Figure 16.

Figure 16: Adding Additional User Properties.

The added User Properties maps to properties of Flownex components and are useful for setting component inputs from Mechanical. As an example, a new User Property can be used to set the heat input of a Node in Flownex, as shown in Figure 17.

Figure 17: A New User Property to Set the Heat Input of a Node.

Different mode options are available for a new User Property, as shown in Figure 18.  The Text option for example can be used for changing option properties or specifying inputs with a specific unit.

Figure 18: Available Mode Options.
Link-Type Components and Node-Type Components

Additional Link-Type Components and Node-Type Components that are not available in the default component set can now also be added by adding a new User Component, as shown in Figure 19. User Properties can be added to these additional components to link inputs for these components to CAD measurements as needed.

Figure 19: Adding Additional Link-Type Components.

When creating a new Link-Type Component, the Type Name for the type of component that needs to be generated can be specified, together with the upstream and downstream connected Nodes.

Figure 20: Specifying Inputs for a User Component.
Updating Flownex Components

Property values can now be updated on existing Flownex components on independent pages that have not been generated by the Flownex Network Builder. This can be done by adding the related component as a new User Component and the User Property associated with the component that needs to be updated.

Figure 21: Updating Component Properties.
Initial Values

The capability has been added for the Network Builder to extract heat transfer surface areas and set the areas as initial values to allow a stand-alone Flownex network to solve. The Flownex network can then be tested to ensure that it has been properly configured, before engaging in co-simulation with Mechanical.

Snap Management

An enhancement has been made to preserve user changes to Flownex component properties, specifically for properties that are not set by the Network Builder. This is done by taking a snap before rebuilding the network with the Network Builder to save the specified inputs. After the Network Builder is finished rebuilding the network, the snap will be loaded to apply the inputs to the components and then the component properties from the Network Builder will be applied.

Co-Simulation Geometry Updates
  • The Network Builder can now automatically rebuild fluid lines and named selections after geometry modifications.
  • Network Builder can automatically send updated properties to Flownex before solving.
  • Rotational speed of all rotating components can now be set via global parameters for easy modification.
General enhancements and stability improvements
  • Support has been added for the latest Ansys 2026 R1 release.
  • A Flownex API module license check has been added when using the ACT extension. This will notify a user if the needed API module license is not available.
  • Support for Mechanical steady-state analyses with multiple load steps and automatic sub step adjustment to improve convergence has been added.
  • Improved Flownex co-simulation data exchange to prevent other solved Mechanical analyses from being invalidated during solves or Workbench updates.
  • The Flownex project now automatically saves upon completion of the co-simulation.
  • Updated communication between Flownex and Mechanical to a standard gRPC-based approach for improved reliability.
  • The Draw in Model button that is shown in Figure 22 has been converted to a toggle button. The toggle button can be used to switch drawings on and off without having to refresh all components to clear the drawings.
Figure 22: Draw in Model Toggle Button.

Reworked Flownex Workbench
Integration

The Flownex Workbench System has been reworked from an SDK add-in into an ACT extension. Given its tight integration with, and frequent use alongside the Flownex–Mechanical coupling, it is included within the Mechanical ACT extension.

Legacy capabilities are fully maintained, including Workbench parameter exchange, steady-state and transient solving, and snap loading. In addition, the following enhancements have been introduced:

  • Flownex project can be embedded within Workbench, enabling Save As and archiving together with the Workbench project, while supporting multi–design point data retention.
  • Flownex saves automatically when Workbench is saved and closes together with Workbench.
  • A new Flownex project can be created from Workbench or a user can attach the project to a running Flownex project.
  • Units are customizable for exchanged data.
Figure 23: Updated Flownex Workbench System.

excel enhancements

general Excel enhancements
Enhanced Excel Editor

All Excel-related spreadsheets have been updated to improve functionality. Most Excel user interface actions – such as adding and editing graphs, cell formatting and many more built-in functions – can now be performed using the newly added ribbon bar, as shown in Figure 24, eliminating the need to open a separate editor as in previous releases. This greatly reduces the need to open the workbook externally in Excel for advanced editing.

Figure 24: Enhanced Excel Editor.
Link Definitions Stored in Comments

Data link definitions are now stored in comments, as shown in Figure 25, and not in a separate file anymore. This allows adding rows and columns or moving cells in the Excel sheet without breaking references. Editing a workbook with an external application will not break the links, as long as the comments are kept in place. It also makes it possible to copy the spreadsheets between different versions of a network while retaining the data links.

Figure 25: Data Link Definitions Stored in Comments.
Cell and Summary List Interaction

Selecting a binding cell selects the corresponding item in the binding list, and vice versa, as shown in Figure 26. 

Figure 26: Binding Cell and Associated Item Selected in Binding List.

Selecting a specific item from the binding list will also open the Properties window of the associated component, saving the user time not having to navigate to a component on the Drawing Page to open an item’s Properties window.

Sheet Layout

A user can control the ribbon and summary view’s visibility with the indicated “Show/Hide” ribbon bar arrows, as seen in Figure 27, to maximize sheet space. The visibility choices are saved per Excel item ensuring that each sheet retains its preferred layout.

Figure 27: Show/Hide Ribbon Bar Arrows.
Search

A Search bar has been added to the Parameter Tables, Input Sheets and Reports. The Search bar will help to easily search for items in a large list, as shown in Figure 28.

Figure 28: Search Bar in an Input Sheet.
Binding List Context Menu

A context menu is now available when right-clicking on an item in a binding list for the Input Sheets, Parameter Tables and Reports, as shown in Figure 29.

Figure 29: Context Menu Available on Items in the Binding List of a Parameter Table.

The context menu allows a user to turn a binding on or off, select the associated component on a Drawing Page and deleting the item from the list.

Binding Mode Display

The items in a binding list will be displayed based on the specified binding mode, as seen in Figure 30 and described below:

  • Normal: Input property for a specific component.
  • Bold: Input property for all components of the same type.
  • Normal underlined: Result property for a specific component.
  • Bold underlined: Result property for all components of the same type.
Figure 30: Binding Mode Display.
Excel Workbook Component Specific Updates

An enhancement has been made to automatically delete Data Transfer Links when the associated binding is deleted.

Input Sheet Specific Updates
New Dialog Window

When a user drags a property from the property grid on to a cell, a dialog window will be displayed as part of the setup, as shown in Figure 31.  A user can then specify the component identifier placement cell and whether the input should be related to a specific component or to all components of a type.

Figure 31: New Dialog Window Displayed when Dragging a Property on to a Cell in an Input Sheet.
Parameter Table Specific Updates
New Dialog Window

When a user drags a property from the property grid on to a cell, a dialog window will be displayed to aid with a minimal setup, as shown in Figure 32.

Figure 32: New Dialog Window Displayed when Dragging a Property on to a Cell in a Parameter Table.
Transposing

The Transpose option will now transpose the full sheet, including user inputs.

Figure 33: Transposing Parameter Table Data.
Edit Parameter Name

The parameter name can now be edited in both the cell and binding list, as shown in Figure 34.

Figure 34: Editing a Parameter Name.
Excel Reporting Specific Updates
Adding Graphs

An enhancement has been made to add a graph on a sheet or on a separate sheet by selecting Add graph or Add sheet graph from the context menu that is available when right-clicking on a binding list item, as seen in Figure 35.

When selecting the Add graph option, the graph will by default be placed under the comment cell. The user can specify the position and size by selecting a range of cells before clicking on the Add graph option. The chart will then be placed in the selected range.

Figure 35: Selecting the Size and Position of a Graph Before Adding the Graph.

Different chart types will be added based on the specific Output Mode, as described below:

  • Table: Line chart.
  • Table with time steps: XY Scatter chart.
  • Values only: Clustered column chart.
  • Table with identifiers: Line with markers chart.

revit builder

Support has been added for building ventilation ducts from Revit models using the Flownex Revit Network Builder, as shown in Figure 36.

Figure 36: Flownex Revit Network Builder Supporting Ventilation Ducts.

python

quick python script component

A Quick Python Script component has been added to the Scripting category, as shown in Figure 37.

Figure 37: Quick Python Script in Scripting Category.

The Quick Python Script uses Python as its scripting language instead of C# like all other Script components in Flownex. The Python Environment embedded within Flownex will be used to evaluate the code.

Figure 38: Quick Python Script Example.

The first time the Quick Python Script is used the embedded Python environment will be installed.

Figure 39: Installing the Embedded Python Environment.

Modules installed in the embedded environment can be used within the script and a user can also access scripts located in the Python project sub-folder.

A “Generate Variables” button has been added to the Quick Python Script. This button exposes generated variables in the property grid, enabling users to define initial values for the variables before the script is executed.  

python console

A Python Console has been added to Flownex and it is located under Windows on the ribbon, as shown in Figure 40.

Figure 40: Python Console Added to Windows Ribbon.

If the Python Console is opened for the first time, it will be necessary to install the embedded Python environment if it has not yet been installed.

The Python Console allows a user to use Python to interact with the current Flownex instance.  The “Fnx” variable can be used to access the local instance, as shown in Figure 41. The “Project” variable can be used to access the currently open project. Python commands can be executed in the Python Console and the result of the commands will be displayed.

Figure 41: Accessing a Local Instance Using “Fnx” Variable.

The Python Console has the ability to show IntelliSense and Documentation for modules, variables etc, as shown in Figure 42. 

Figure 42: IntelliSense and Documentation Shown.

Scripts located in the Python subfolder of the project can be executed and these scripts can be fully interactive with user input from the Python Console.

The “Stop” button can be used to cancel any long running script or command. The “Open Folder” button will open the Python sub folder of a project. This is the location to use for any Python script that a user would like to use.

cantera

The Cantera library has been added to the embedded Python environment that ships with Flownex. This will allow users to easily extend the combustion models in Flownex.

merging projects

Support has been added for merging drawing pages into another project. Incoming pages with matching names can be added as new or replace existing pages. Users can now create or preserve views during the merge and choose whether to retain incoming or existing component properties.

Figure 43: Merging Drawing Pages in a Project.

bulk renaming

The capability has been added to rename multiple components simultaneously. Users can prepend or append strings, find and replace text within existing identifiers, or replace identifiers based on defined naming rules. Support has also been added to include links during renaming and to rename all occurrences within snaps.

Figure 44: Bulk Rename Window.

dark mode

Dark mode has been implemented for Flownex. The Dark Mode setting is found on the Settings ribbon, as shown in Figure 45.

Figure 45: Dark Mode Setting on Settings Ribbon.

The colour mode can be set explicitly to Dark Mode, Classic Mode (light mode) or to Use System Setting, which will apply a user’s system setting.

Figure 46: Flownex Project in Dark Mode.

pipe schedules and roughness selection

The Pipe and Bend schedule database has been expanded with the latest versions of 30 commonly used international pipe size standards, covering both European and USA standards for various materials.

Figure 47: Pipe Schedule Database Index.

The Roughness database was also updated to contain more internationally recognised sources. The sources are now also clearly stated for reference.

Figure 48: Roughness Database Index.
minor enhancements

Solving Options on Drawing Pages

Drawing Pages can now be enabled or disabled without losing the individual solving settings on components or links by selecting Enable Page Solving or Disable Page Solving, as shown in Figure 49. Enabling or disabling solving of all components will change the individual solving settings on components as well.

Figure 49: New Solving Options on Drawing Pages.

reset units

The capability has been added to reset all the changed units on properties to the current unit system. This can be done by clicking on the “Reset units to active units” button in the Edit Unit Systems dialog as shown in Figure 50.

Figure 50: Reset Units to Active Units Button.

api

Due to COM type library versioning, unregistercomapi.bat from version 9.1.0, as shown in Figure 51, must be executed before registering and using the COM API in older versions.

Figure 51: Unregistercomapi.bat File in Installation Folder.

single file projects

It is now possible to open a single file project (.projz file) by dragging and dropping the file into a Flownex project with open drawing pages.

graphs

A “Copy as Table” option has been added to copy a graph’s data as a table to paste directly into Excel. This option eliminates the need to save the graph as a CSV file first.

Figure 52: New Copy as Table Option on Context Menu.

The default names for copying and saving images and CSVs of graphs has also been improved.

Data Transfer Links

Data Transfer Links will now be shown as dashed when the link is not connected between two components.

Figure 53: Difference Between Data Transfer Links that are Not Connected and Connected Between Components.

Generic Charts

A display type option has been added to the Generic 2D, 3D and 4D Charts to display data as logarithmic, as shown in Figure 54.

Figure 54: Logarithmic Data Display on Generic 3D Chart.

Finned-Tube Heat Exchanger

A Generic option has been added as a Tube geometry type option for the Finned-Tube Heat Exchanger, which allows a user to specify the tube area and tube circumference for the tubes, as shown in Figure 55.

Figure 55: Generic Tube Geometry Type Option on Tube Side.

Heat transfer results have been added to Sub-Element results on the Tube Side of the Finned-Tube heat-exchanger, as shown in Figure 56.

Figure 56: Sub-Element Heat Transfer Results on Tube Side.

Word Reporting

When importing Excel Sheets into Word Reports, hidden sheets will be excluded. Hidden files will also be ignored when scanning the project for report templates and generated reports. Microsoft Word and some other external editors will create a temporary hidden file during editing that must be ignored by Flownex.

New Pure Fluids

Ethylene Glycol and Propylene Glycol mixtures have been added as Pure Fluids, as shown in Figure 57:

Figure 57: Ethylene Glycol and Propylene Glycol Mixtures Added as Pure Fluids.

Composite Heat Transfer

An option has been added on the Composite Heat Transfer element to obtain the disc convection heat transfer area directly from cavity geometry inputs, as shown in Figure 58, when the Composite Heat Transfer element is connected to either a Rotor-Rotor or Rotor-Stator Cavity.

Figure 58: Obtain from Disc Geometry Convection Area Option.

Reality DC Room

The 6SigmaDCX Simulation component has been renamed to Reality DC Simulation, as shown in Figure 59.

Figure 59: Reality DC Simulation Component.
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