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FLOWNEX SE 8.8.0 (2017)

Flownex® SE 8.8.0 revives the thermal-fluid system engineer’s dream design tool, with yet another release inclusive of advanced industry leading features. With Global engineering software companies adopting, integrating and co-simulating with Flownex® its holistic capabilities have enormously improved.  

Major enhancements include a first of a kind generic nuclear reactor model, many new components as a Bulk Air Cooler, Cooling Tower and a whole new electrical library.

Flownex’s 8.8.0 release presents exceptional libraries, components, speed, accuracy, integrability, and ease of use which continues to propel its superiority in the 1D system’s engineering market.



Ansys Workbench Integration

An add-in has been developed for ANSYS Workbench that allows Flownex® to be added to Workbench. The Flownex® add-in lets users add Flownex® analysis to Workbench, open Flownex® from Workbench and perform studies with Flownex®. It operates in a way similar to the existing Excel add-in in Workbench. Figure 1 shows the Flownex® add-in in Workbench.
Fig. 1 - Ansys Workbench Integration

Generic Nuclear Reactor

Flownex® has expanded the Nuclear Reactor capability to simulate Molten Salt (liquid fuel) Reactors (MSR), Liquid Metal Cooled Reactors (LMCR) and High-Temperature Gas-cooled Reactors (HTGR) of any geometry. The new “Generalized fuel zone” in the Flownex® Nuclear Reactor model is capable of handling any fuel geometry and any fluid type. It expands the geometry capability to plate fuel, cylindrical fuel rods, spherical fuel elements, irregular cross section fuel (like the cross-shape produced by Lightbridge), as well as prismatic block fuel used in some HTGRs. Appropriate pressure drop and heat transfer correlations can be selected from the built-in library or defined by the usr. For neutronic calculations, the “Generalized fuel zone” can provide temperature feedback, as well as heat generation in all solids and in the core coolant.

Bulk Air Cooler | Component

A Bulk Air Cooler component has been added to simulate heat exchange between process water and an air stream. The heat transfer is mostly driven by mass transfer between the air and water stream and to a limited extent by convective heat transfer. In the case of bulk air coolers, the primary objective is the cooling of air using the evaporative cooling of the process water. The modelling of these bulk air coolers fundamentally relies on Flownex’s capability to model mixtures of air-water-vapour fluids using the two-phase and non-condensable mixture model. By specifying a single input called the “Factor of merit”, the complete operating envelope of the bulk air cooler can be modelled.

Cooling Tower | Component

A Cooling Tower component has been added to simulate heat exchange between process water and an air stream. With cooling towers, however, the primary objective is the cooling of process water using evaporative cooling to the air stream. The modelling of these cooling towers fundamentally relies on Flownex’s capability to model mixtures of air-water-vapour fluids using the two-phase and non-condensable mixture model. Two methods are implemented in Flownex® for the modelling cooling towers. The Factor of merit model uses a single parameter to characterise the operating envelope thereof. An alternative approach of somewhat higher fidelity is based on the Merkel model approach, and divides the cooling tower in three distinctive zones, namely: Spray zone – water distribution into the cooling tower, normally using spray nozzles. Fill zone – water is distributed onto or between a fill media to increase the surface contact area between the water and air. Rain zone – water from the fill zone “rains” into the collection pond to allow further contact between water and air. Both forced draught, as well as natural draft cooling towers, can be modelled in Flownex®.

Pipe Elevation Profile

An elevation profile for pipes has been added. This allows the easy simulation of complex pipelines with a single discretized pipe. Figure 5 shows the Pipe Profile Editor window that can be used to specify the elevation profile for pipes.
Fig. 5 - Pipe Elevation Profile, i
Fig. 5 - Pipe Elevation Profile, ii.


A utility has been created that can run through the projects in the validation pack on a customer’s PC and ensure that they solve correctly and generate the correct results. The utility will create a report with the status of the run, as well as the other relevant information relating to the run.
Fig. 6 - Validation

Electrical Library

Fig. 7 - Electrical Library

The Electrical Library has been updated to improve its usability and broaden its application. Basic components such as the Resistor, Capacitor and Inductor were added to serve as building blocks for large load systems. Three phase inputs and results will prove to be more valuable to the user. Characteristics (such as more impedances forming the equivalent circuits) are added to the Induction Motor and the Transformer for an improved component specification. The added Motor component allows the user to specify a motor characterised by a torque-speed curve. The Motor and Induction Motor component can execute with a mechanical-flow network using a connection to the Flownex® Shaft.

Links To Other Software

  • The Fluent – Flow solver coupling has been updated to make it easier to use. Both the server and journal file versions were updated.
  • Simulink, Matlab and Labview links have been updated to work with API and not with Memory Map anymore. The Memory Map functionality has been removed due to 64bit compatibility issues.
  • A Help File has been added for the Python Link.
  • The ability to run multiple Flownex® instances via the API has been added. This is a setting that can be turned on and off in the application settings.



  • Flownex® is now available in 64bit.
  • Added a Property Monitor window that can be used to pause the simulation during transients when properties attain certain values. It can also highlight properties when they have changed.
Fig. 8 - Property Monitor
  • Improved complex values parsing. Users do not have to put spaces in between the complex and imaginary parts anymore. 
  • Added the ability to transfer data using Data Transfer Links before and after each flow solver iteration in transient/dynamic simulations as this was only possible for steady state simulations.
Fig. 9 - Data Transfer Link - Transient Behaviour
  • Use FIPS compliant cryptographic provider so Flownex® can run on FIPS compliant computer setups.
  • Added the capability to preserve an active page when automatically re-opening all pages.
  • Added the ability to prevent Flownex® from opening newer databases.
  • Added a button to the License Setup window so that license information can be copied to the clipboard.
Fig. 10 - License Setup window with Copy to Clipboard button
  • Added the capability to allow multiple instances to run through the API. A setting was added that turn this option on and off.

Compound Components

  • Added a Create Copy option to the compound components context menu as seen in Figure 11.
Fig. 11 - Create Copy option Option in Compound Context Menu

Fluids, Charts & Lookup Tables

  • Made data references that use others (like mixtures) copy or move their dependencies with them – the user is asked for confirmation.
    Improved the Error reporting when a Chart or Fluid was not found to identify the item that was using that Chart or Fluid.
  • Made the Positive Displacement Pump chart show all of the lines on its charts at the same time as only the selected line was shown.
  • Made the Variable Speed Pump show all the lines on its charts at the same time as only the selected line was shown.
  • Issue a meaningful error when a Material Property Table only contains no valid data.
  • Save units selected for Constant Properties in Fluid and Material dialogs.

Flow Solver

  • Made pipe diameters and areas dynamic so that it can be changed within sequential iterations and during transients. 
  • Added Fixed Exit Temperature option to the Flow Resistance element.
Fig. 12 - Flow Resistance Element with Fixed Exit Temperature
  • Added Pump head result to Variable Speed Pump. 
  • Diameter and Wall thickness have been added as a result for all relevant components. 
Fig. 13 - Diameter and Wall Thickness Results
  • Prevent Fix on sovler value options from being used in Steady State
  • Updated the Pressure Relief and Pressure Regulating Valve icons, as seen in Figure 14.
Fig. 14 - Pressure Regulating Valve and Pressure Relief Valve Icons
  • Improved film compounding in Film Convection component to use appropriate upsteam cooling slot conditions.


  • Added an example that shows how to build a page with Visualization components using a Script.
  • Added an example that shows how to issue warnings and errors from a Script. 
  • Simplified the way that scripts convert to and from Repository Scripts – the “Yes/No” option on the input grid was removed to make it less confusing. 
  • Made operator overloading for C# consistent between doubles and integers so that doubles and integers can be used in the same way in the Quick Scripts. 
  • Made Variables setup grid disabled when Script is a Repository Script in Quick Script. 
  • Added a flag to Iterative Script to indicate it is the last iteration.

Console Version

  • Prevent console from opening newer versions or projects.

Nuclear Reactor

  • Added the reactivity unit “mN” as well as Dollar reactivity values. 
  • Changed Heat Transfer options to Neutronics options on Reactor dialog. 
  • Added Flow and Solid volumes in ARR file. 
  • Added Average moderator temperature to increment results and to ARR file. 
  • Added Fission power as a result on Reactor. 
  • Duplicate power specifications were taken off the Reactor Chart Zone and the transient and steady state Reactor inputs were simplified. 
  • Preserve column and row geometry in Nuclear Reactor settings when inserting rows and columns in the Nuclear Reactor Geometry editor. 
  • Added options to add rows and columns above and below and before and after on Nuclear Reactor Geometry editor. 
  • Added Moderator, Fuel and Xenon reactivity results. Changed External reactivity name to Control rod reactivity, as seen in Figure 15. 
Fig. 15 - Nuclear Reactor Results
  • Indicates ports with a P on the zones in the Reactor Geometry editor.



  • Fixed the Python Link example, as it had to be updated for the new library structure.
  • Prevent user from removing root scenario in Actions Setup dialog–it causes an exception.
  • Fixed problem where Simple Convergence Bar did not show full convergence when the Temperature Solver is turned off even though the solution converged.


  • Prevent crash that occurred when On and Off values of a toggle button are both the same, and the user solved the network in steady state. An error is issued indicating that they are the same.
  • Fixed the display on canvas of complex double values with units as only the modulus value was shown.
  • Make sure everything is updated (for example text on the Drawing Canvas and IO Boxes) when changing the component type from the context menu.

Fluids, Charts & Lookup Tables

  • Fixed database assignment of data references when multi-editing–selecting Fluids/Charts on many components with the property grid caused an error.
  • Removed wrong unit from Poisson’s Ratio in the Solid Properties Script.
  • Fixed Mixture Material Test dialog to work with more than ten fluids.
  • Fixed problem with warning messages given for mixtures where the mass fraction is 0 in the viscosity and conductivity calculations.


  • Fixed the problem where Quick Script variables were over written during snap load.
  • Fixed the problem where exceptions were caused when calling mixture script functions with wrong amount of fractions.


  • Fixed the problem where IO Boxes were not pointing to correct components when copied and pasted into compounds.
  • Fixed problem that sometimes occurred when exposing heat transfer side properties in a compound, as the upstream and downstream side sometimes got swapped.
  • Fixed launching of a user’s custom compound component Help from component tree.
  • Fixed the problem where changing component type to a compound broke the connectivity.
  • Compounds within compounds did not display their links correctly if the outer compound contained links with the same name.
  • Fixed problem where Composite Heat Transfer elements failed to solve in compounds when the compound was reloaded.

flow solver

  • Fixed the problem where a meaningful error was not issued when the Ambient radiation area is zero in the Composite Heat Transfer element.
  • Set Roughness option to Darcy-Weisbach when Non-Newtonian fluid is used on pipes.
  • Prevent unnecessary warnings when the Vapour pressure table is empty in the Fluid Properties window.
  • Fixed the pressure drop results reporting when choked flow occurs in pipes.
  • Added warning for slurry networks that fail to converge on account of non-constant background fluid properties.
  • Changed “Pressure drop including elevation” result to “Pressure drop” to avoid ambiguity.
  • Removed element inlet condition results since element upstream conditions now reflect appropriate conditions under all circumstances, e.g. when connected to an Open Container.
  • Fixed lower limit of Secondary Loss Factor calculated for Mitre Bend component that lead to errors.
  • Added “Subcooling” and “Superheat” results to Nodes.
  • Changed results of some variables on incremented elements to use average values instead of the results from the first increment.
  • Fixed visibility of Nusselt number result on flow elements.
  • Fixed Adiabatic Flame writing negative values to node mass fractions.
  • Added two-phase critical pressure result on elements.
  • Fixed Open Container not working with two-phase flow with evaporation.

Download full release notes here.


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