CFdesign 9.0

By Al Dean

CFD (computational fluid dynamics) software is traveling much the same road to mainstream adoption as finite element analysis (FEA) software traveled — and still is — for the past five or so years. Among the developers working toward that goal, Blue Ridge Numerics has been in the vanguard, pushing its CFdesign application and the “up front design"concept to the fore. So, let’s take a look at the major updates in CFdesign 9.0.Accelerated Solving

The first major news, as ever for any computationally heavy application, is an update to the solver technology that underpins CFdesign. For the 9.0 release, the new Accelerant solver offers some new proprietary CPU optimization algorithms that were developed to calculate more efficiently. As usual with these types of things, it’s all relative. The benefits you can draw depend entirely on the work you’re doing. According to Blue Ridge, while a smaller study might be completed 40% quicker, when working with extremely complex studies,tests indicate speed improvements on the order of 2,000 percent.

> > CFdesign 9.0 uses native CAD assemblies and new automation features to deliver a window into system performance up front in the design process.

Alongside solver updates, another common enhancement for any simulation release is a series of updates to the meshing tools, and 9.0 is no different. While automated meshing has become de rigueur in the move toward mainstream adoption, there are many different takes on the process. Blue Ridge’s approach combines new geometry diagnostics, which inspect a model to highlight potential problem areas, with new tools to automate the sizing of the mesh. This conducts an initial topological interrogation of the model to find the most appropriate element sizes.

But perhaps more critical is the refinement process. Again, this uses the topology of the model as well as finding a “global” element size,and it also refines the mesh by both adding and removing element concentrations and densities where appropriate. In structural analysis circles, this usually revolves around handling small features, but within the world of CFD, this is extended to handle small gaps and the geometry’s proximity to other geometry. This gives the system plenty of elements to accurately predict how fluid will interact in such small voids.

< < The intelligent automation of mesh sizing in CFdesign 9.0 removes a source of potential error and allows engineers to spend more time on product reliability and innovation.

Finally for meshing, CFdesign 9.0 brings new tools for handling extruded forms. In many cases, parts or geometric features are prismatic in nature, so it would be prudent to optimize their meshing(and hence their calculation). CFdesign now identifies regions that are suitable for extruded meshing — where a constant cross-section is present — and uses a specific form of element (wedge) to describe those forms. While the applications for this technology are widespread across all industries, it’s particularly useful for parts with high-aspect ratios, like heat sinks, fan blades, and sheet-metal enclosures, as it greatly reduces element count (and as such, calculation times).

Automation & Electronics

Blue Ridge Numerics has done even more work on automating the CFD process with its new Rules on Parts functionality. This allows you to generate filter-type rules that inspect a CAD part’s filename upon import and automatically assigns a material definition based on the name of the part. This is the first release of this technology and —while many organizations don’t define their part names based on material — if you can categorize your parts to single out specific component sets, you can automate the materials assignment process. This is pretty common within the electronics design space, so it will be a major benefit to groups working in that field.

> > A “mouse over” on a microchip reveals critical thermal management data including board, junction, and case temperatures.

Also on the electronic component front, CFdesign 9.0’s compact thermal model tool allows you to define two-resistor microchips for heat-transfer simulation. Only two parameters are required: Theta JB and Theta JC. Once you define these parameters, CFdesign calculates the board junction and case temperatures, then the heat transfer between those (such as junction and board, junction and case) can be derived.The system supports BGA (ball grid array), PBGA (plastic ball grid array), TBGA (taped ball grid array), FC-BGS (flip chip ball grid array), QFP (quad flat pack), PQFP (plastic quad flat pack), NQFP(no-lead quad flat pack), and SOIC/SOP (small-outline/small-outline package) microchip configurations.

Fans

Elsewhere on the intelligent part creation front, CFdesign 9.0 now lets you define fans much more intelligently. In previous releases, you would have to import the full explicit geometry for a fan component for use in a study; from this release onward you can now define it using a standard fan velocity profile. This allows you to quickly incorporate into your simulation an idealized fan component that holds the correct velocity distribution data. Traditionally, this would have required some rather intensive rotating region analysis.

Solar Loading

The final major addition in version 9.0 is Solar Loading. Solar Loading lets you incorporate into your analysis studies transient electromagnetic heat transfer from the sun, a phenomena that can affect the performance of outdoor security cameras, climate control systems,power utility transformers, and such. This feature includes radiation through transparent media and even shows shadowing based on the movement of the sun. Simulation set up is simple: Specify time of year,time of day, and location on the globe using the database in CFdesign,or assign specific latitude/longitude coordinates.

Up front CFD

Many developers are looking to bring CFD to the mainstream market, to reach a point where the average designer or engineer uses fluid and heat simulation tools as part of the daily work process. The concept is that they not only generate full geometric descriptions of new products within their workhorse 3D MCAD system, but they also accurately predict product performance. Within that CFD market, there are many different approaches being taken. For example, there are developers with a history in traditional, expert-driven CFD codes looking to commoditize their high-end products into easier-to-use packages by providing mainstream interfaces to their existing code base. There are also those that have used a similar background but have chosen to develop new systems from scratch for this mainstream market. Then there are developers that set out their stall in the mainstream camp from the very beginning. Blue Ridge Numerics has always been in this last category, and this heritage is reflected in CFdesign.

< < Select a geographic location, a date, and time of year and CFdesign 9.0will show the transient effects of the sun on the product and its environment.

CFdesign is CAD-integrated in a specific sense: It reads native CAD data, imports geometry, assembly structure, and now other information(such as material definition). Then CFdesign allows you to work in an environment that’s tailored to the CFD workflow. This differs from other vendor approaches, which integrate directly into the CAD system interface — this isn’t a criticism or praise, just a statement of fact.

What’s most important is that you have the ability to take the master3D data from your MCAD system and carry out the simulation that you need and feed the results back into the product development process.What all of the updates made in CFdesign 9.0 mean to your business is that you can get the results out of the system, gain a better understanding of how your current product iteration is going to perform when built, and where you need to make changes or improvement — all within a much shorter space of time than has traditionally been possible. And that means two things, you get higher quality products into the market quicker and gain competitive advantage — and that’s what good technology is truly for.

Al Dean is Technology Editor of the UK’s leading product development and manufacturing journal, MCAD and is Editor of Prototype, for the rapid prototyping and direct manufacturing industry, both available by clicking here. Send your comments about this article through e-mail by clicking here. Please reference “CFdesign 9.0” in your message.

CFdesign 9.0
Blue Ridge Numerics, Inc.
Charlottesville, VA