FLOWNEX 2020 – UPDATE 1
The new Update to Flownex® SE for 2020 expands the possibilities of simulating real-world systems.
Some exciting features included with this release include: built-in functionality to generate system resistance curves within seconds, force calculations for pipe sections, interfacing with CAESAR II for detailed pipe stress analyses, a co-simulation link to the latest version of 6SigmaDCX, along with many other improvements that are listed below.
LIST OF ENHANCEMENTS
System Resistance Graphs
Force Calculations for Piping Sections
CAESAR II Integration
Flownex® provides a very easy to use interface to work with CAESAR II. By using this interface Flownex® can calculate dynamic loads for pipe stress simulations for water hammer cases or pressure waves.
The interface allows a user to import the geometry for a piping system from CAESAR II directly into Flownex®. This saves a user time and also eliminates possible errors that could occur when users need to manually duplicate piping systems in Flownex®.
Flownex® also provides an intuitive way to define the piping sections for which users wants the net forces to be calculated. These calculated forces can be automatically exported in a time series that is easily imported into CAESAR II.
6Sigma is a world leading tool for data centre simulation and a link to 6Sigma has been added. The link allows users to quickly setup combined simulations and allows both steady state and full transient simulations.
Typically, a detailed model of the inside of a data centre can be connected to a complete external cooling model in Flownex®, where all the cooling towers, pumps, heat exchangers etc. is modelled in detail. This allows a complete system simulation that is not available in other software and opens up a whole new spectrum of possible efficiency improvements in both design and operation mythology.
Nuclear Reactor Building Scripts
The ability has been added to build a nuclear reactor using a script. This script reads information from a reactor geometry chart and builds a corresponding reactor. The reactor is built on a separate page in the user interface. Users have access to all of the elements and nodes that defines the reactor.
There are several advantages using this capability. The first advantage is that all the inputs to the elements and nodes that build the reactor can be verified. Furthermore, all internal results are available and finally, the internal connectivity and structure can be manually modified by users if needed.
Example scripts are available on request. Some components have been added to aid in the reactor building, which include a Porous Flow Element and a Composite Conduction component. They are found in the Reactor Building Blocks category in the Nuclear library, as seen in Figure 9.
Angled T-Junctions and Y-Junctions
The existing junction functionality has been enhanced to include the ability to model angled T-junctions and Y-junctions, as seen in Figure 1.
Many of the junction losses as defined in “Internal Flow Systems, 2nd Edition” by D. S. Miller have been implemented, thereby extending the previous functionality from the limited perpendicular junction options. These junctions are available for selection from pre-defined junction types, as seen in Figure 2.
The trace element modelling capability has been significantly expanded. Previous versions only allowed for homogeneous mixing of trace elements on nodes, where users now have the following additional capabilities at their disposal:
- The ability to filter trace elements from the network.
- The ability to specify selective throughflow of trace elements between nodes, thus resulting in non-homogenous mixing of trace elements within nodes.
- The ability to specify trace element sources and sinks on nodes without the precondition that they enter or leave the system via mass sources or sinks defined for the carrier fluid.
- Modelling trace element decay during transients using the trace element decay constant.
Filtering and selective throughflow of trace elements are specified on flow element components and sources or sinks and decay are specified on node components, as seen in Figure 13.
Isentropic Head Compressor
The screenshot preview that displays in Windows Explorer when the preview pane view is activated, has been updated. In the past, the entire Flownex® window area was captured and sometimes it included overlapping windows. Now only the main item inside Flownex® is captured in order to show the most relevant view of the project, as seen in Figure 18.
Psychrometric Boundary Condition
The following enhancements has been made to the heat transfer components:
- Implemented the option to calculate conduction area from the circumference of the connected pipe.
- Made Kugeler-Schulten correlation available for the Convection element.
- Implemented second order convection calculation for a Convection element connected to a Node. This allows convection calculations to be done using the mass weighed average upstream temperature of the flow elements connected to the node that the convection calculation is performed on. This functionality should result in faster grid independence for subdivided flow fields such as those used in a reactor geometry.
- Implemented dispersion for porous flow elements to account for the enhance heat transfer resulting from the disruption of flow in porous media. The dispersion is modelled as increased diffusion heat transfer within the fluid.
- Implemented length over diameter warning for Dittus-Boelter and two-phase flow applications.
- Added the Overall convection heat transfer coefficient and Convection coefficient as results for Convection elements.
The following enhancements has been made to the Nuclear components:
- Second order convection can be specified in the reactor chart.
- Dispersion can be turned on in the reactor chart.
- An error will be given when not all reactor ports that are defined in the chart are connected.
- Added gamma_f0, gamma_m0 and gamma_x0 to the fuel reactivity, moderator reactivity, and Xenon reactivity equations to allow the user to specify a constant offset independent of the prevailing temperatures.
- Changed “Cross section x neutron flux” input in die neutronics chart to “Xenon cross section x neutron flux” to clarify the use of the input.
- Implemented warning that normalized control rod insertion depth when upper or lower limit has been reached.
- Updated “Reactivity” result description to “Control rod reactivity” to clarify its meaning.
- Added warning if neutronics parameters such as Normalized Power, Normalized concentrations of neutron precursor isotopes, Normalized concentrations of decay-heat producing isotopes, Iodine concentration or Xenon concentration go negative and are limited to zero.
- Changed point kinetics error condition to be issued if fission power equal to zero and reactivity greater than the decay neutron fraction, Beta.
- Updated Kugeler-Schulten calculations to interpolate between Nusselt numbers calculated at Reynolds number = 100 and Nusselt numbers of 4 (at Reynolds number = 0) for Reynolds numbers smaller than 100 to correctly reflect the documented range of applicability of the Kugeler-Schulten correlation.
Heat Exchanger Component
The following enhancements has been made to fluid mixtures:
- The capability has been added to specify a mass sink with mass fractions specified to nodes that are internal to a network. This allows for the selective removal of fluid components from a fluid stream to model the action of a filter or membrane. This functionality is not available on boundary or edge nodes as the transfer of mass is an advection problem and boundary conditions cannot be propagated in the opposite direction to the flow.
- Psychrometric results are calculated for all two-phase non-condensable mixtures featuring Water as the two-phase fluid.
The API now provides users with the ability to create copies of components and links. Several functions have been added to the NetworkBuilder interface in order to facilitate this. These functions are documented in the API help file. Examples of how to use these functions have been added to the “NetworkBuilderScripts” demo project located under Demo Networks on the Flownex® Start Page. The Python example “3. Simple Network Builder” has also been updated to show how to use these functions. This example is available in the Help menu under Python Link.
Added the capability to specify an angle for the Louver parallel and opposed 3V blades damper types.
Fixed a bug where flow still occurred even when the level of the Container Interface was at zero.
Limit the emissivity on the Surface Radiation component to values between 0 and 1.