Flownex Release 2016 - Smart just got smarter for thermo-fluid design and analysis engineers

2016 has been an exciting year of expansion and development for Flownex, our development team continues to lead the way in systems thermo-fluid simulation software development. With a major focus on software integration and complete turbine simulation capabilities Flownex SE provides tremendous cost, time and risk savings to our users with a design and analysis accuracy that is unbeatable to date.

Luke Davidson – International Marketing & Channel Manager




30 years ago Flownex was brought to life by Professor Gideon Greywenstein, he had a vision to produce a tool that would create extraordinary value through engineering excellence. Flownex has ever since strived to keep his words true, and to resonate his vision.







The advanced pebble bed reactor component has been changed so that it can simulate various kinds of reactors with different kinds of fuels. The ability has been added to specify the neutronics calculations using a script. This enables the simulation of a wide variety of reactors like molten salt reactors as well as solid fuel reactors. The Advanced Pebble Bed Reactor component was changed to the Nuclear Reactor component and Advanced Pebble Bed charts were changed to Reactor Geometry charts. Existing networks using the old Advanced Pebble Bed Reactor will still function, the component icons might change if the default icons were used. All the related charts will be moved to the required folders in the charts and lookup tables. Figure 1 contains screenshots of these changes. For more information see the nuclear chapter in the components user manual.

To allow for more customised heat transfer correlations an extra coefficient named A was added to the Dittus Boelter equation on the reactor geometry chart and the composite heat transfer element in order to be able to model molten salt reactor heat transfer. Figure 2 is a screenshot of the new geometry zone specification window with the new input field. The generic correlation for the Nu number is new expressed as:1. NuclearReactor 3 

1.NuclearReactor 11. NuclearReactor 2

Figure 1: New Nuclear library components (LHS), New Nuclear charts and lookup tables (RHS)

NuclearReactor 4

Figure 2: New term (A) added to the Dittus Boelter Nu number correlation inputs


A positive displacement pump component has been added to the Flownex® component library. Both rotary as well as reciprocating pumps can be modelled via user defined performance characteristics for volumetric flow rate vs. rotational speed at various pressures. The component allows the user to define viscosity scaling characteristics as well. Additionally power and net positive suction head margin results are also calculated.


PositiveDisplacementPump component

Figure 3: New positive displacement pump


The user can now change component types after it was inserted onto the drawing canvas without losing their links and also keeping all inputs with same category and name. Use this by right clicking on a component on the drawing canvas and choosing the “Change Component Type” option as shown in Figure 4.

3. ChangeComponentTypes

Figure 4: Change Component Types in Flownex®


A default report (called Results Overview in Flownex® SE) was added that is run after steady state and transient; this is done so users have a report without even setting up any reports. The default report is presented as a drawing page tab (Figure 5).

Excel® reports, input sheets and parameter tables are now shown on their own tree like other pages as depicted in Figure 6. Refer to the relevant sections in the user manual for detailed descriptions on how to use the tree.

Reporting 1Figure 5: Default report (Results Overview) as Drawing Page tab in Flownex®
4. Reporting 2Figure 6: Excel® reports, input sheets and parameter tables in Project Explorer


Fields that are data transferred to or fields that are set from input sheets or parameter tables are now disabled on the property grid. This allows users to know which fields will be overwritten from somewhere else. E.g. in Figure 7 the length of Pipe – 1 can’t be changed because it is connected to the length of Pipe – 0 via a data transfer link.

5. InputPropertyGrid

Figure 7: Disabled fields during data transfer


The effects of film convection compounding have been added to the film convection component. The film compounding accounts for the effect of the upstream liner coolant films on the downstream liner coolant film effectiveness. Through selecting the associated upstream film convection components from a drop-down list, Flownex® applies the compounding equation to the affected elements resulting in more accurate film effectiveness prediction.

An option was added to use integrated film effectiveness based on the correlation type instead of the more conservative low effectiveness value at furthest position from the slot exit. The option is specified in the Film Convection Component inputs. (See Figure 9)

 6. FilmConvectionComponent 1

Figure 8: Schematic of film accumulation

FilmConvectionComponent 2

Figure 9: Integral interpolation scheme option


A P&ID like drawing mode was added. P&ID symbols were added for the relevant components and links are all black in P&ID drawing mode. The setting for this is located on the Settings ribbon and is shown in Figure 10. Flownex® also ships with a wide variety of P&ID symbols that can be used as images for components, they are found by selecting the master database from the image selector gallery.


 PID drawing mode

Figure 10: P&ID icon on the Settings ribbon


The demonstration (demo) networks have been updated and are set up to illustrate how Flownex® can be used to solve many different type of engineering problems. The networks shown range from simple networks such as determining the flow rate through a pipe connected to tanks at different elevations to more advanced examples such as a three shaft Brayton cycle used to produce compressed air.The demo networks begin with a problem statement accompanied by a physical representation of the problem and are followed by solution in the form of a Flownex® network. These networks are different to the tutorials as they do not include step by step instructions in building the network but are rather a good point of reference for intermediate users looking to better understand how to model particular systems using Flownex®. The demo networks can be found on the start page when Flownex® is opened as shown in Figure 11.


Demonstration networks

Figure 11: Demo networks on Flownex® start page


A drag coefficient calculation option has been added for bolts on Rotor-Rotor and Rotor-Stator components. The drag coefficient can be selected for round, cylindrical, hexagonal, screw, flat and flush rivet bolt heads (See Figure 12). The Rotor-Rotor and Rotor-Stator components have been updated to allow inputs for multiple rotor and shroud speeds. This allows for modelling twin-spool engines. Figure 13 shows the changes to the inputs window.

RotorRotor RotorStator 1

Figure 12: New inbuilt bolt drag coefficient options

RotorRotor RotorStator 2

Figure 13: New multiple rotor and shroud speeds inputs for Rotor-Rotor and Rotor-Stator components


An advanced inputs option has been added to all flow elements to allow the user to easily recognise non-essential inputs - this simplifies inputs on all elements, especially on the pipe element.

10. Advanced input 110. Advanced input 2

Figure 14: New advanced input option


Added a DWSim based fluid generator to replace the CoolProp generator. DWSim has many more compounds available as well as different user selectable property estimation methods. The DWSim import option is located on the Import ribbon as can be seen in Figure 15.

11. Importing

Figure 15: DWSim import icon on the Import ribbon