Many heating ventilation and air conditioning related components, including ducts, transitions, dampers, junctions, combiners, elbows, screens, entrances and exits have been added to the Flownex® component database, as seen in Figure 1. These components allow for easy modelling of HVAC ducting systems in line with the ASHRAE standards.
Volume Flow Boundary Conditions
The boundary condition specification options have been expanded to include the specification of volume flow boundary conditions, as seen in Figure 3. The volume flow specification will be used to calculate the equivalent mass flow boundary conditions commensurate with flow conditions. The thermodynamic condition can be based on the current node conditions or user specified reference conditions.
Psychrometric Boundary Conditions
It is customary in HVAC applications to specify psychrometric boundary conditions for moist air. A new Psychrometric Boundary Condition is available in the Nodes and Boundaries Library, as seen in Figure 4.
Flownex® now allows for the specification of wet bulb temperature, relative humidity and humidity ratio for moist air mixtures in addition to the psychrometric results that are available for two-phase non-condensable mixtures. The calculation of wet-bulb temperature has been extended to include frost bulb temperatures.
A new fluid named Humid Air has been added to the Mixed Fluids in the Master database for use with the Psychrometric Boundary Condition component.
A psychrometric chart can now be plotted for humid air. The psychrometric chart together with plotted component operating points can assist the user to graphically analyse the psychrometric processes of a system.
Graphs Through Flow Paths
The ability to plot a property, for example, the total pressure through a network has been added.
The property of components along a defined flow path is plotted. Flow paths can be defined by selecting the start and end components of the flow path. The context menu can then be used to quickly define a new graph.
The option to plot a pressure and enthalpy diagram for two phase fluids has been added, as seen in Figure 8.
The pressure-enthalpy operating point of a component using the Fluid Property Graph can therefore be plotted.
FMI Master Capability
Result Layer Improvements
The Result Layers has been updated to show density, energy source, mass source and an indication if choking is present, as seen in Figure 10.
The result layers were also improved to shade the area over the connecting fibres between nodes and elements, which makes it much easier to see the results graphically in large networks.
- Added the ability to create data references through the API. This allows users to create charts such as pump charts, valve charts, etc. by using the API alone.
- Added a Python example to demonstrate adding charts through the API.
- Added a demo network example to demonstrate adding charts via C# scripts inside a project.
- Added Visual Studio 2019 compatibility to the extendibility feature.
- Made it possible to set the chart and other non-double properties on components using the MATLAB coupling.
Script Editor Improvements
One of the best ways to quickly generate a script is by using a Quick Script component. By using the Quick Script to add all the variables you need and then clicking the show entire script button, you can then copy and paste this code to an ordinary script to customise it further. To make this process easier, buttons and context menu items were added to the script dialog to select and copy script code in the Script Editor.
Intellisense has been added to function scripts like the Pipe Friction Factor script and the Heat Transfer Coefficient calculation scripts.
Search and replace functionality were added to all the script editors. Press Ctrl+F to activate the search dialog or Ctrl+H to activate the Replace dialog.
Several additional property types were added to the Quick Script – this include data references, component and property selectors. The primary reason for this was to make it possible to use fluid functions in the Quick Script as well as properties from other components.
An example script that interpolates on a 4D Generic Chart has been added – this is a good generic way to easily add lookup tables to simulations.
The example scripts were changed so that they are not contained inside compounds anymore. This makes it easier to see the actual script code as well as to modify the scripts. The compound-based example scripts are still available in a category called “Legacy Compound Scripts”, as seen in Figure 17.
- The scripts will now only start executing once an initial flow field has been established. This is usually after five iterations depending on the solver settings.
- A function has been added so that a user can specify whether data transfer should happen after the initialise method and before solving the Flow Solver components.
- The user can now set Data Reference Properties, Integer, Boolean and Option Properties from Parameter Tables.
- In order to distinguish between Result and Input parameters in a parameter table heading, the results parameters are shown with a darker grey colour.
- The layout has been improved for Parameter Tables with different DPI screens and custom screen scaling.
- The Parameter Table active conditions drop down now only shows the first thousand items. This was done to increase GUI performance when using very large Parameter Tables.
When saving details for a server license the Node Locked license details are now reset and vice versa. This makes it easier to switch between Server and Node Locked licenses.
- Added the ability to change fluid property/characteristic graphs axes units.
- Added the ability to plot the convection/radiation properties of a Composite Heat Transfer or a Distributed Heat Source along the length of one of the connected pipe components. Previously all points were plotted at the same length.
- Added borders to graphs. White (hidden) by default.
Added several new online map sources, as seen in Figure 18.
The console version of Flownex® can now be used to run parametric studies or sensitivity analysis. The user can specify the command line parameter -sensitivityandparametric to run the current active sensitivity analysis configuration in a project.
- The Nuclear Reactor now allows the use of multiple Pebble Bed Fuel Zones in transient cases. Previously the chart based neutronics implementation only worked in transient cases for one fuel zone.
- Added an error when the sum of fractions for heat input for all the zones in the nuclear reactor does not equal one. For cases when the sum is zero, this will be a warning only.
- Added toggle buttons to ribbon menu to easily turn on and off result file generation settings, as seen in Figure 19.
Added secondary loss inputs to the primary and secondary side of the Plate Heat Exchanger component.
- Added lower limits for the following inputs:
- Number iteration Temp1
- Number iteration Temp2
- Number iteration Temp transient.
- Changed name of “Use iterative temperature solver” input to “Use BiCG matrix solver for energy equation solution”.
- Add properties on the Scheduler to indicate if warnings and errors have occurred. These properties can be used in parametric studies etc. to monitor success of solving over all the runs. The warning and error count were also added as properties.
Distributed Heat Source
- Added the ability to specify the heat input associated with the Distributed Heat Source component using a local specification option.
- Added errors and warnings for the Distributed Heat Source when incorrectly connecting Distributed Heat Source components to each other or when the Distributed Heat Source is over specified.
- Fixed problem with heat fractions not being applied during transient for distributed heat source.
Jet Pump Component
Added loss coefficient results to the Jet Pump component.
- The Momentum addition inputs will now only be available on pipes and not on all components.
- Implemented warning when small L/D values are used along with Dittus-Boelter and also for two phase flow.
- Added the option to allow the specification of mass source conditions with fixed temperature/enthalpy, hereby allowing energy source calculations that are not based on ambient conditions.
Secondary Loss Component
Extended secondary loss component modelling capability to include Liquid-Gas mixtures, particularly for modelling oil-air mixtures in gas turbine lubrication systems.
Nozzle and Rotating Nozzle
Implemented input area option on Nozzle and Rotating Nozzle components, allowing for non-circular orifice shapes.
Added results for increments in discretized Labyrinth Seals.
Jet Impingement Convection
Removed upstream cross flow link in Jet Impingement component and instead use net inflow to fluid node. This enables modelling networks with jet impingement where the flow direction of the cross-flow stream is not pre-determined, but forms part of the solution.
Rotor-Stator and Rotor-Rotor
Added disk area results for increments in cavities. This allows more detailed heat transfer modelling and calculating thrust forces.
Added gauge pressure result.
All Element Types
Added humidity ratio result on all elements when used with the Humid Air fluid.
The following items were added to the Validation Pack:
- Flow Resistance
- Secondary Loss
- User Specified Pressure Drop
- User Specified Pressure Ratio
- Cross Junction
- Finned-Tube Heat Exchanger
- Plate Heat Exchanger
- Shell & Tube Heat Exchanger
- Distributed Heat Source
- External Pipe Heat Transfer
- Slurry Networks
Nodes and Boundaries
- Psychrometric Boundary Condition
- Volume Flow Boundary Condition
- Nuclear Reactor
- Custom Vortex
- Forced and Free Vortex
- Labyrinth Seal
- Rotating Annular Gap
- Rotating Nozzle
- Rotor-Rotor Cavity
- Rotor-Stator Cavity
Turbos and Pumps
- Turbine and Compressor
- Basic Valve
- Check Valve
- Control Valve with Loss Coefficient
- Pressure Regulating Valve
- Pressure Relief Valve