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Just one numerical simulation contains a wealth of information – we can gain a lot of insight on how a device performs, and from that, we can infer how to make that device better. To confidently recommend one design over another, though, we’ll need to run more than one simulation. As our device knowledge is informed through simulation, we can expect to make numerous geometry/part modifications to the original design. How quickly we can turn these changes around will determine how many simulations we can run within our time budget. Without a highly efficient and flexible workflow, we might find ourselves in the position of being less certain of our final product recommendation. Risky.

 Now, you’ll be hearing a lot soon about Design Manager, a native capability within STAR-CCM+ v12.04® to do design exploration – that’s not this story. Instead, I want to share how two mouse clicks can now get you quickly from that first simulation to the next one, and to the one after that and the one after that...

 First, some history. In STAR-CCM+ v9.04, we introduced logic-based “Filters.” For example, you could create a Filter to return all the geometry parts that contain the name “chip.” Using your Filter to make your part selection in an Operation saves you the trouble of having to find and select all of these objects in the tree by hand. Faster. Less error-prone. Repeatable. Good.

 But, if you were to then add another “chip” geometry part, you had to go back to your Operation, re-apply your Filter and update your selection. In other words, the part selection wasn’t dynamic. To address this, we delivered Query-Based Selection in STAR-CCM+ v10.06. Automatable. Better. But still limited in coverage to just Operations, Displayers and Derived parts. Why is this limiting? Because Regions were statically linked to parts, so if you added, modified or removed parts, you would need to update your part selection for your region manually.

 This is now a thing of the past. In STAR-CCM+ v12.04 we’ve extended Query-Based Selection to apply to Regions, Boundaries, Sub-Groups, Interfaces and Reports. Faster. Less error-prone. Repeatable. Automatable. Better still.

 To show how this can help you, let’s consider the simulation of a packed bed reactor for dry reformation of methane to produce hydrogen gas. These reactors contain randomly packed solid catalyst particles which can be various shapes and sizes:

 

catalyst_particle_shapes.png

 

Our operating conditions may be fixed to a narrow range, so if we want to improve our reactor performance, the choice of particle size, shape and number is going to be critical. Let’s consider our workflow starting point to be a simulation (with the solution cleared) in which the physics continua (fluid and solid), regions, boundaries, interfaces, reports, scenes and displayers have already been set up. In the case shown below, we want to replace the existing packed bed containing cylindrical shaped particles with seven wedge-shaped holes in each (at far left), with a new packed bed based containing smaller tri-lobe shaped particles (at far right). We’ve got four dynamic queries in play that we will use to assign…

A   …any geometry part with a name containing “__particle” to a Unite operation (this was possible in previous versions).

B    …the Geometry Part generated by the Unite Operation to the solid particle Region.

C    …all Part Surfaces containing the name “__particle” to a Region Boundary defined in the fluid region and another defined in the solid Region (the same dynamic query is used for both regions).

D    … all Part Surface Contacts (which are created when the Volume Extract Operation is run) to an interface.

two_click_workflow.png

Now, with your .sim file set up this way, when you hit the Generate Volume Mesh button on the toolbar, our first of two mouse clicks, the Operations pipeline is executed. What you end up with is a .sim file, meshed and ready to go – all Parts to Region assignments are automatically done. The second of our two mouse clicks, hitting the Run button, is almost anticlimactic in comparison. Your simulation starts running and any derived parts, reports and scene displayers that also use Query-Based Selection get automatically updated, as shown in the figures below.

 

 A cylinder derived part (intersecting the packed bed near the reactor wall) is unrolled to compare hydrogen gas production rates between the two packed bed designs.

 Data Focus highlights areas of higher (in color) compared to lower (grey) catalyst site blockage.

 

Reducing the workflow to two clicks did take some preparation and the methodology does rely on a part naming convention. When does it make sense to go through the extra steps? If we want to examine just 3 different particle sizes for each particle shape pictured above, that’s 21 different random packed bed geometries; 21 .sim files that need to be consistently set up; 21 sets of reports and plots and scenes that need to be consistently compared. And, if that isn’t enough of a reason, there are two more great new features in STAR-CCM+ v12.04 - Replace Assemblies and 3D-CAD Part Synchronization - that also leverage the benefits of Query-Based Selection.

Faster. Less error-prone. Repeatable. Automatable. Better still, indeed. The bottom line is this: Some initial preparation to set up your dynamic queries is the logic-based choice.  

 

Products New: 
Matthew Godo
STAR-CCM+ Product Manager
Stephen Ferguson
Marketing Director
James Clement
STAR-CCM+ Product Manager
Joel Davison
Lead Product Manager, STAR-CCM+
Dr Mesh
Meshing Guru
Ravindra Aglave
Director - Chemical Processing
Karin Frojd
Sabine Goodwin
Director, Product Marketing