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Engineering Edge

How to make the most of the XML functionality in FloTHERM & FloVENT

Your complete guide to XML functionality in FloTHERM® & FloVENT®

By Andy Manning, Application Engineering Manager, Mentor Graphics

With the release of FloTHERM™V9.3 and FloVENT™V7.9 Computational Fluid Dynamics (CFD) software products, the implementation of an XML schema for use in those two products was completed. For those unfamiliar with the concept, the XML format is described by a variety of tags and expected inputs, with the collection of these tags and inputs formally known as an XML schema. The XML schema available for FloTHERM and FloVENT specifically defines tags such that the resulting file can be read directly into the software. The resulting file is readable and structured, as shown in the example, thereby lending itself to widespread adoption and readily available software authoring tools.

The standard installation of FloTHERM and FloVENT includes many application examples and common XML schema building blocks, which would allow engineers to become familiar with the format and implementation of the functionality.

The availability of the XML schema offers several advantages to the engineer in considering different applications. Firstly, it allows the creation of objects which are geometrically repetitive in their construction, for example, folded fin heat sinks, data centers, etc. which would normally be time consuming or tedious to build. Secondly, it allows the engineer to define their own SmartParts beyond those currently available in FloTHERM and FloVENT. SmartParts are parametrically defined macros which can be used to create common electronic cooling or built environment objects, for example, enclosures, fans, CRAC units, diffusers, etc. Library objects of these items can then be readily stored for later use. For instance, chimneys are used to isolate the hot air created by data center cabinets. The combination of cabinet and chimney can be readily defined using the XML schema. Thirdly, the use of the XML schema ensures adherence to Best Known Methods Standardization (BKM), where modeling errors can be avoided, and user-independent results produced. Finally, it allows the engineer to bypass the use of the Graphical User Interface (GUI) during the pre and post processing modeling phases and instead use simple software utilities, such as Microsoft Excel’s macro functionality, to manipulate the creation of the model and interrogation of results.

Figure 1. Data Center Model Generation, Solution and Results Using XML

Through bypassing the GUI of the parent software itself, there are two clear benefits. The first is that the process becomes very streamlined and straightforward. There is no need to open/close application windows, construct models, define plots, etc. The advantages of using the FloTHERM or FloVENT (CFD) products are therefore available to field engineers who would not necessarily have the experience to utilize such tools. The second benefit is that it allows the CFD software to be embedded into other third party or company created propriety software packages, and thereby become integral with company design processes. Input/output boundary conditions such as pressure or temperature data can be readily transferred between the FloTHERM/FloVENT software and the third party software. Alternatively, geometrical information from the third party software could be used via the XML schema to create CFD models. As an example of this latter usage, information on data center racks, CRAC units, etc. that is readily available in Data Center Infrastructure Management (DCIM) software can be parsed to create CFD models. The simulation results could then be fed back into the DCIM software.

Let’s look at an example of how this could work using the illustrated case.

  • Data entry of equipment and data center layout. This could be done via an audit or parsing of information from the DCIM software.
  • FloVENT model creation via Excel macro. This would be via a simple button click.
  • The model can then be manipulated in different ways, depending on the requirements. A couple of options could be:
    • Import into FloVENT model for further refinement and simulation. The post-processing capabilities inherent in FloVENT, for example, animations, cut plots, Capture Index values, etc. can then be used to readily demonstrate the appropriateness of the data center HVAC design.
    • CFD simulation via Excel interface and subsequent results import into pre-formatted Excel spreadsheet. In the example shown, the rack supply temperatures have been color coded according to the operational limits of the rack. If desired, results can then be fed back into the DCIM software.

Figure 2. Compact PCB Generation in Virtual Wind Tunnel Using XML XML

As noted above, FloTHERM V9.3 and FloVENT V9.3 completed the implementation of the XML schema that was started in V9.1. All geometric objects and SmartParts included in the two software packages can now be represented and manipulated. Further, the latest version allows PDML Referencing, so any existing geometry or library item to be used with macro or scripts, thereby removing the need to parametrically describe all objects in the XML applications, and simplifying the creation of the input file. This is demonstrated in the second example, which considers the creation of a compact model of a PCB in a wind tunnel. Here, native XML objects are used to describe the wind tunnel, the Solution Domain, Fixed Flow, and Monitor Point, while PDML Referencing is used to identify the model of the PCB to be tested.

Figure 3. Example XML Schema File

So, how to get started? The standard installation of FloTHERM and FloVENT includes many application examples and common XML schema building blocks, which would allow engineers to become familiar with the format and implementation of the functionality. Further technical information and consulting services are available from local Application Engineering resources.


A full implementation of a FloTHERM/FloVENT XML schema is available in V9.3 of the software. The inclusion of the schema provides clear advantages in the creation, solution and post-processing of CFD models and allows companies to tailor the software environment to better fit their organization’s specific needs and work flow.

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