FLOWNEX® SE 2018 - Update 1 Release

We've launched our latest update to our Flownex SE 2018 release.

Some of our major enhancements is adding a thermostat and thermostat bypass component, scale drawing measurements, liquid mixtures and more. 

Luke Davidson | International Marketing & Channel Manager

Thermostat and Thermostat Bypass

Thermostat and Thermostat Bypass components were added to the Flownex® component library. Thermostats are required in systems that control the heating or cooling of the working fluid close to the desired temperature. This component is typically found in engine cooling systems or air-conditioning of buildings. The component level behaviour is therefore similar to a valve that will change its opening as a function of temperature.

The new “liquid-gas” fluid model in Flownex® is ideal for the accurate prediction of the flow regimes and pressure drop of air-oil flow in many industrial applications. For example, in aero-engines, air and lubrication oil are mixed in a bearing chamber, which is subsequently drained by a scavenging system comprising of a pump and piping system where the air and oil are separated.

The complex nature of this two-phase flow, characterized by turbulence, a deformable phase interface, phase interaction, phase slip, and compressibility of the gas phase makes the mixture difficult to analyse and therefore makes these lubrication systems difficult to simulate.

To overcome these difficulties, Flownex® has added an updated set of governing equations to describe the interaction of the phases. Additional pressure drop and flow regime correlations have also been added to provide a commercial solution to the design of pressurised lubrication systems.

ThermostatThermostat Bypass

Figure 1: Thermostat and Thermostat Bypass.

A typical thermostat has two flow paths, namely the primary flow path and the bypass flow path, however there are cases without a bypass, and therefore Flownex® allows the modelling of a Thermostat with and without a Thermostat bypass. The opening of the Thermostat is dependent on the inlet static temperature and specified as a chart. The opening of the Thermostat Bypass is obtained from the opening of the Thermostat, also defined by means of a chart. The secondary loss for both the Thermostat and Thermostat Bypass as a function of their respective openings are calculated from the user-defined charts for secondary loss versus opening.


Figure 2: Close-loop network with a Thermostat and Thermostat Bypass.

Scale Drawing Measurements

The scale drawing functionality has been expanded. A scale drawing ribbon was added to the toolbar with all the scale drawing related functionality.

Scale Drawing Ribbon bar

Figure 3: Scale Drawing Ribbon bar.


The user can specify the scale and coordinate system of an imported drawing with two known coordinates on the drawing canvas. This allows the drawing origin to be away from the zero-point on the axis and also simplifies specifying the scale. The drawing scale and coordinate system can be changed at any time and the components will be scaled accordingly.

Generate scale drawing dialog

Figure 4: The Generate Scale Drawing dialog.

Point and line measurements can be drawn on top of the imported picture. The line will determine the correct lengths and coordinates from the scale and coordinate system of the imported drawing.

Point or line measurement

Figure 5: Adding a point or line measurement.

The coordinates of the points and length of each line can be connected to any input fields on components. They are connected without data transfer links to avoid cluttering the drawing canvas.

Input property link to measurement on drawing canvas

Figure 6: Input property link to a measurement on the drawing canvas.


Fields associated with the measurements are greyed out. Moving the points or lines will update the coordinates and lengths while keeping the associated fields updated.

Input property link greyed

Figure 7: Input property greyed out when linked to a measurement.


The point and line measurements or the components and links that are drawn on top of a scale drawing picture, can be hidden and shown when required with the buttons on the Scale Drawings ribbon tab.

The opacity of the background picture can be changed to make it easy to see the measurements on the drawing. The opacity slider on the toolbar is used for this.

Global Parameter Displays on Drawing Canvas

Right-clicking on any property in the input or result grid will display a context menu with a new option called “Display on Canvas”. This allows the user to choose the location where to display this property for all components of the same type. The same context menu of the relevant property on the property grid is used to remove what is displayed on the Drawing canvas.

Adding input or result property

Figure 8: Adding an input or result property using the right-click context menu.


In the configuration screen, the user can change the advanced configuration options like the number of significant digits, or whether the caption should be displayed.

Configuration screen for displayed parameters

Figure 9: Configuration screen for the displayed parameters.

Script Debugging

The Scripts can be debugged if a debugger is installed on the computer. Visual Studio is recommended for debugging. The Debug button is located on the Script editor.

Script editor with added debugging

Figure 10: Script editor with the added debugging.

After clicking the Debug button then the user will be prompted to select which debugger to use.

Prompt to select appropriate debugger

Figure 11: Prompt to select appropriate debugger.


A breakpoint can be placed in the relevant function requiring debugging and the run button can be pressed in the debugger to continue. The debugger will break as soon as your chosen line of code is hit.

Breakpoint added to debugger

Figure 12: Breakpoint added to the debugger.

Liquid Mixtures

The ability to specify a fluid mixture consisting of multiple liquids was added. The user can select various liquids as pure fluid components in a fluid. The mass fractions for each component are specified similarly for gas mixtures. Flownex® will calculate the mixture thermodynamic properties and the user can specify the mixing rules for the transport properties (viscosity and conductivity) by selecting one of the pre-defined mixing rules or coding a script for custom mixing rules. The mixture will be treated as a single-phase liquid in the Flownex® solver. A Help button was added to direct the user to the appropriate location in the User Manual discussing the mixed fluid theory.

Multiple liquid mixture specified in Flownex
Figure 13: Multiple liquid mixture specified in Flownex®.

Specify Drawing Grid Spacing

The size of the grid on the drawing canvas can be changed on the page inputs. To access the page inputs right-click on a page and choose “Edit Page” on the context menu.

Specifying drawing grid spacing

Figure 14: Specifying drawing grid spacing.

Change Location of Identifier and Description Text

The location of the display can be changed in the project settings under “Drawing Text Settings”.

Changing location of Identifier and description 

Figure 15: Changing the location of the Identifier and Description.

Added Button to Copy Used Data References to Project Database

A button was added enabling the user to copy all the charts and lookup tables from the databases located in the project to the project database. This is useful when using a company database and it is necessary to send a project to another user that does not have that database.

Copy data references to project database

Figure 16: Copy the Data References to Project Database.

Added Confirm Delete Dialog on Data References and Categories

The user will be asked for confirmation before deleting a data references to prevent accidental deletions.

Confirmation delete dialog

Figure 17: Confirmation dialog before deleting a data reference.

Master Database Location

The location for the built-in master database that ships as part of the Flownex installation was changed. The name for the database folder is now “Master” (it was previously in a folder called “Project” in the installation folder).

Nuclear Reactor

Added friction factor and flow area to Detailed Reactor Output file.


The Python resource files have been updated. Firstly, a getting started guide has been added to assist new users with installing Python and installing the required libraries for using the Flownex API. Another example has also been added to show how Python can be used to automatically build a network from a CSV-file using the API. Furthermore, the Flownex.py file has been updated to automatically determine your Flownex install directly from the registry entries created when Flownex is installed.


The Cooling orifice was removed and will be replaced with a Nozzle in the existing networks.

Bug Fixes

Drawing canvas

  • Fixed the problem when pasting a component the component was not always placed at the location where the preview showed.
  • Changed the Ctrl+Drag+Copy mechanism to work the same way as other software.
  • Fixed the problem where background image selection for graphs did not work.
  • Fixed the problem when first Copy-Paste and then undoing of components on geometries left viewless components in the project.

Property Grid

  • Fixed the issues during multi-editing of components and the double fields having different selected units but the same values. i.e. when the length is 1mm in one component and 1m in another.


  • Fixed the problem when specifying an end time on the main scenario in actions causing the user interface to freeze.

Nuclear Reactor component

  • Fixed the problem where the solid material selection drop-down box freezes in the general fuel zone in the Nuclear reactor component.
  • Fixed the problem when specifying fractions in the general fuel zone where double precision numbers did not exactly add up to 1.0 for the Total solid fraction and Total heat fraction.
  • Fixed the problems when the solution produced NaN results for moderator temperature and reactivity when moderator fraction is set to 0.0.

Flow Solver

  • Fixed convergence criteria for the Two-phase tank component where solving seemed to have converged whilst still solving to converge the Two-phase tank component.
  • Fixed the problem causing the Flow resistance component not to solve when the initial pressure drop is zero.
  • Fixed the problem with the loading of snaps for non-circular pipes and number in parallel not set to unity.
  • Fixed the problem with liquid-gas mixtures during transients with Two-phase tank component not solving.
  • Added a mass fraction relaxation parameter to solver inputs for liquid-gas mixtures.

Flow Solver Components

  • Fixed an error in the Reynolds number calculation for Orifice in pipe transition component.
  • Fixed the problem where the mass fraction boundaries are not correctly applied when specified in the first time step of a transient when changing setting from mass source fraction to mass fraction boundary.
  • Added a warning when the British standard orifice’s solution is in the two-phase regime.
  • Added a warning when two-phase conditions exist at an element outlet when exit temperature is specified.


  • Removed redundant set of polynomial equations in the fluid properties editor.


  • The py file has been updated to typecast the component and property variables used in the SetInput and GetOutput functions fixing an AttributeError that occurred in version 8.9.0.


  • Corrected conversion factor from Pa to mmH2O.

Manual Updates

The following sections in the Flownex® General User Manual have been updated:

  • Updated the Scale Drawing functionality and Excel importer component specification in the Importing chapter.
  • Updated the Graphic User Interface chapter to include:
    • Parameter Display Setup to the Results ribbon tab.
    • The ability to change components’ Identifiers and Descriptions text locations.
    • Grid X and Y spacing on the page properties.
  • Added Script debugging to Libraries chapter.
  • Updated the Fluid mixtures to include Liquid mixtures setup and theory in the Charts and Lookup Tables chapter.
  • Added copy all used Data References to the Project database functionality to Databases chapter.


The following sections in the Flownex® Library Manual have been updated:

  • Added the Thermostat and Thermostat Bypass.


The following tutorials have been updated:

  • Added Tutorial 40 illustrating how to use the Scaled Drawings functionality.