AFT Blog

Click on the junction to be moved once to select it. Then hold the Ctrl key down while you drag the junction icon and the pipes will remain in their current location. Note this results in the pipes being disconnected from the junction.

While we usually think of building a system model in the Workspace (and, of course, we can have multiple models within a file in different scenarios), you can have multiple, disconnected system models within the work space simultaneously. This has many uses, including facilitating parametric modeling. For example, you're modeling a system with a defined supply flow and want to evaluate the results for various supply flow rates. After building the model, select the whole model (Edit/Select All or ctl+a), then duplicate it (Edit/Duplicate or ctl+d) as many times as desired. For each instance specify a different supply flow and,...

Using “Specified Heat Rate In Constants” for the thermal model of heat exchangers can often cause problems in system models.  The reason why is because this thermal model type causes the heat exchanger to act like an “assigned heat input” junction as does an assigned flow junction does for providing constant flow rates.  Another problem is that this thermal model can cause unrealistic temperature changes across a heat exchanger.  When the heat rate is specified and the mass flow rate and heat capacity are calculated based on the system solution, the temperature change will be whatever is required to maintain...

Many components, such as isolation valves, elbows, and adjacent area changes, do not need to be modeled graphically when a simple k factor will suffice. In these cases, the AFT Fathom user can simplify and avoid unnecessary workspace clutter by integrating this data into a single pipe specification, using the Fittings & Losses tab. Fathom has a built library of component loss data provided by Miller, Crane, and Idelchik. The Fathom user can quickly and easily pick from a database of components, enter the quantity, and click OK. It is important to note, however, that Fathom uses the size of...

All AFT Products automatically generate backup files each time you save your model. Backup files will be saved to the same location you have saved your model file to. They will have the exact file name as your model, but rather than having the extension *.fth, *.aro, *.imp, etc., they will have the extension *.001, *.002, *.003, etc. Every time you click save while working in your model, a new backup file will be created. If the maximum number of backup files already exists, the new backup file will overwrite the oldest backup file. The maximum number of backup files...

After you receive your AFT software , you will probably wonder how to learn the software quickly so you can begin using it.  AFT provides a very handy Quick Start Guide for each software product in English Units and SI Units.  These quick start guides are short, concise, would take maybe a day of your time, and are extremely powerful to assist you in producing highly accurate and advanced models! With larger companies, sometimes the AFT software will go straight to the IT department for installation and the engineer may never see the hard copy of the quick start guides. ...

Filters and screens impose a pressure drop that varies with flow rate. The variation is non-linear, but manufacturers will often provide only one data point for pressure loss at the design flow rate. Using a single point, or constant pressure drop, can produce significant inaccuracies in your model. With this in mind, AFT offers the “Fill As Quadratic” option for entering loss data.   Using only a single point, “Fill As Quadratic” will create two additional points for you. This first is simply 0,0; zero flow produces zero pressure drop. The second point is 2 x Flow and 4 x...