Truly innovative desktop fluid flow analysis
FloWorks from NIKA
FloWorks continues the current trend towards design centric analysis tools, offering desktop fluid flow analysis.
Significantly, FloWorks is the first fluid simulation application specifically developed for Windows NT rather than UNIX allowing it to be fully integrated into SolidWorks.
It also uniquely offers full associativity with the design data allowing efficient design iteration based on analysis rather than intuition.
Flow analysis has long been in the domain of specialists and FloWorks offers unparalleled ease of use and cost effectiveness for a highly complex engineering analysis.
As with many of the design analysis tools, ease of use is achieved by hiding complexity from the user.
But this is not to underestimate the quality of the interface and integration achieved with SolidWorks.
Analysis projects can be set-up manually or using a practical, no frills wizard.
This steps through the selection of a suitable project template, which by default generates a new SolidWorks configuration specifically for the study allowing features or parts to be suppressed without affecting other configurations.
Further wizard steps include selection of the system of units, of which there are plenty including the option for custom combinations and the specification of an internal or external study.
The study medium of liquid or gas can be selected from a substance database.
Up to ten substances can be combined within a project, specifying the relative proportions of each.
Advanced options include heat transfer, time dependence and gravitational effects.
The final wizard page sets initial model parameters such as pressure, temperature and density plus velocity.
By setting good estimates the analysis run time can be reduced.
Turbulence settings such as intensity, length, energy and dissipation can also be set.
On leaving the wizard a FloWorks tab is generated in the SolidWorks FeatureManager containing a tree giving access to the project input data and results.
The benefits of integration with the modeller become immediately apparent.
For internal flows, model openings need to be closed in order to create a fully closed volume.
This is simply done by adding SolidWorks features.
Historically the transfer of a design to analysis was problematic as it was not the part that was required but the empty space.
Not only does this mean considerable time and effort in modelling but also discourages design iteration as the process needed to be repeated every time the design changed.
For FloWorks the empty space is automatically detected from the parametric part models and can be simply re-generated each time the design changes.
The interface allows analysis goals to be set using non-expert terms.
In order to achieve accurate results goals must be defined for each parameter being studied such as pressure and mass flow.
Flow conditions and surface goals can similarly be set, selecting model geometry and accessing dialogs using standard SolidWorks commands and right mouse button menus.
Once the study is fully defined, the analysis can be run.
A virtual box is automatically generated bounding the part or assembly to define the study domain.
The space within this box is divided into slices and cells per slice determined by the model geometry and the goal accuracy previously defined.
Once a base grid is generated automatic iterative adaptation takes place to allow for wall singularities such as small gaps and sharp corners.
This adaptive process aims to improve accuracy where necessary whilst saving time and computational effort wherever possible.
During the mesh generation process a dialog shows progress and statistics indicating the number of cells generated.
A tally of irregular cells indicates where any mesh problems have been encountered and results may be inaccurate.
Once the mesh is complete the solver runs with a multiple tabbed dialog.
Again progress is tracked together with graphs on the goals tab plotting each of the defined goals to indicate convergence.
On the preview tab a results plot is updated on a selected plane every ten iterations.
Right clicking inside the preview area allows the plot parameter such as pressure, temperature or velocity to be selected.
Once the pre-defined engineering goals have been achieved the solver stops.
After the monitor dialog is closed, results can be displayed directly in the SolidWorks windows.
Since the SolidWorks graphics area can be split into four panes, different results can be displayed simultaneously in each view.
The FloWorks tree in FeatureManager gives access to each of the result types.
Cut plots are defined by selecting and offsetting a SolidWorks plane.
Again the parameter to be displayed on the plane can be selected and the number of decimal points set to give a useful plot.
By default colour plots are generated but vector plots, flow trajectories and isolines can also be displayed.
Flow paths can be displayed as simple trace lines or as coloured ribbons to also indicate velocity variations.
Since the results are displayed on the SolidWorks model it can be rotated to best visualise the data.
Multiple results can be displayed in the same view and can be switched on or off as required.
By defining a single point in a SolidWorks sketch, the flow line from an individual start point can be tracked through the model.
In addition to the model plots, goal summary data can be exported to Microsoft Excel.
This can be for all or just user selected goals and the generated Excel file contains multiple sheets containing a summary, a convergence plot for each goal and the raw plot data.
Excel is also used to graph variation of any of the parameters along a path through the model.
This can be a simple planar SolidWorks sketch or 3D spline but it must pass entirely through the fluid domain.
Documented reports incorporating model plots and analysis data can be automatically exported to Microsoft Word.
In addition to the data inserted according to the selected template, additional comments can be added manually.
Model plots can also be saved as .BMP bitmaps for manual reporting.
Once a study has been run variants of the design can readily be explored.
An entire analysis project can be cloned as the stating point in order to avoid the need to duplicate the goal definition process.
This essentially generates a further SolidWorks configuration allowing component features or parameters to be edited without altering the initial study.
Although parts and features can be suppressed directly in SolidWorks, this can sometimes lead to rebuild errors if other parts or features reference the suppressed details.
To get around this FloWorks offers a component control tool allowing parts to be disabled for the analysis only and hence not altering the rebuild process.
Although the intelligent interface, named IDI is intended to simplify analysis preparation by providing a simple step through process, many manual overrides are also available.
User defined unit systems for instance can include any combination of units and decimal places while material properties can include dependencies such as density values as temperature varies.
Such custom materials can be organised in user folders in the material database.
Materials can also be globally replaced within an analysis project to aid multiple iterations.
Mesh handling tools include a geometry checker to ensure the model is a perfectly closed volume and therefore suitable for analysis.
The mesh itself can be manually adjusted in situations where the smallest flow gap is an order of magnitude smaller than the nominal.
A preferred method is to simply define a surface goal on an adjacent surface but if necessary the resolution can be increased by raising the number of cells but this can significantly increase the solve time.
Advanced capabilities include conjugate heat transfer studies allowing a total heat release to be applied to a component and the performance of surrounding fluid flows to establish dissipation performance.
Transonic shock wave and external supersonic flows can also be studied.
Density changes at high speed are handled using compressibility effects.
FloWorks is a truly innovative product both technically and in terms of the target users.
Although in this first release it does not offer full top end functionality such as semi-permeable studies or electrostatics, it is entirely consistent with the design orientated SolidWorks philosophy.
The available functionality covering internal and external studies, steady and transient flows, multi-phase studies, flows with boundary layers, laminar and turbulent flow and heat transfer will be adequate for many applications.
Accuracy has not been validated as part of this review but as with design-centric FEA and Moldflow tools it is likely that misinterpretation of results by non experts is a greater danger than incorrect data.
The key issue is that it makes flow analysis accessible to a far wider audience, offering the prospect of a better design understanding at an earlier stage.
The interface certainly limits the learning curve and encourages experimentation and the automatic adaptive meshing essentially hides all the clever bits.
Results can be readily visualised and collated into reports and the integration with SolidWorks is seamless including extensive use of configurations and entire project set-ups saved within the design files.
Direct associativity between the design data and the analysis tool enables multiple iterations to be handled without the traditional struggle to define the empty volume and reapply parameters.