AFT Blog
Welcome to the Applied Flow Technology Blog where you will find the latest news and training on how to use AFT Fathom, AFT Arrow, AFT Impulse, AFT xStream and other AFT software products.
AFT Arrow & AFT xStream New Features Coming Soon
We recently discussed the new features coming out in AFT Fathom 13 and AFT Impulse 10. Now let's talk about the compressible gas and steam side of the product launches. You may be more familiar with AFT Fathom, as it is our flagship incompressible steady state analysis product. AFT Arrow is its counterpart for compressible steady sta
Gas and Steam Transient Analysis is Freaking Hard!
Whew! That was a lot of hard work! As of Monday, April 12, 2021, AFT xStream™ is loaded up and ready to go. And to help you simulate things you have only guessed at before.When we engaged Fred Moody a few years ago to teach a short course at AFT that covered compressible gas and steam transients, we were not certain a commercial quality product cou
Is there steam on your (Microsoft) Windows? How ASME Steam Tables came to be.
In the modern world there are many things we take for granted – especially in first-world countries. Among them are the reliable availability of water and electricity. To our homes. To our workplaces. Just about everywhere.Engineers also take things for granted. One of those is reliable data on the properties of steam and water. But it was not alwa
For Geeks Only – Solving Transient Compressible Flow Equations
Be forewarned that today I am going into full on geek mode and talk about equations for transient compressible flow. These equations are in the form of hyperbolic partial differential equations (PDEs'). If that did not scare you away yet, then you may be as much of a geek as I am! With some fancy mathematics, three PDE's can be converted into six o
Don't throw a fit over your Fitting K Factors - Part 1: Fittings & Losses in AFT Fathom
AFT Fathom, AFT Arrow, AFT Impulse, and AFT xStream all have a tab in the Pipe Properties window called "Fittings & Losses" which allows users to quickly specify K factors for components within a pipeline such as valves, elbows, and area changes. The Fittings & Losses allow you to simplify your model and avoid workspace clutter by int
Steam Piping in Nuclear Power Plants Is Not As Safe As Commonly Believed
As if we all need something else to worry about, right? But I am afraid it is true. The concern stems from how fast steam acoustic waves steepen as they transmit through a system. This steepening causes transient forces on the steam piping much higher than conventional methods predict.When I was beta testing AFT's latest software product, AFT xStre
Would Newton Approve of How You Use His Law?
Improve Safety & Accuracy in Pipe Force Predictions ASME B31 piping code requires engineers to consider loads on pipes from waterhammer, steam hammer and other fluid transients. In principle, this means using Newton's Second Law which he published over three centuries ago. In 1687 to be specific. And in Latin if you want to read it in it
Restore Your Sanity, and Your Corrupted Model Files
Users occasionally contact AFT saying they have lost their model files or cannot open them. Can you imagine spending hours, days, or months building models, and all of a sudden, the progress and work is gone?! If it happens right before a deadline, the engineer will most likely have a minor panic attack, and feelings of anger, depression, or hopele
Declutter Your Natural Gas Model
I don't have any tips for decluttering your garage or office desk, but I can offer you a tip on how to declutter your natural gas model. Perhaps it will save you some time as well in the design phase. As engineers, we like details and will enter as many as possible into our models. I've seen several AFT Arrow and xStream models with natural gas mix
My Recent Visit With Newton and Galileo
I suspect Europeans who live near world history sites just accept this as normal. For a backwater American like me, it is amazing to come across the final resting places of Isaac Newton and Galileo. I recently had that privilege in London and Florence. On my 60th birthday in early April, I had the privilege of visiting Westminster Abbey. Among the
Compressor Maps
A Compressor Map in AFT Arrow allows you to more accurately model the full range of operating conditions for a Centrifugal Compressor junction. AFT recognized the need for this specific feature from customers via support requests and consulting projects. Well, good news…this capability is here! The featu
Reciprocating Compressors and Modeling Approaches
The release of AFT xStream 3 brings with it reciprocating compressors for your gas transient models! Positive displacement compressors now have two subtypes: fixed flow rate for a steady mass or volumetric flow rate, as was present previously, and the all-new reciprocating compressor option. The reciprocating compressor model is for compressors in
Awesome Annotation Tool Additions
The Annotation Tool has new shapes and customization options which will help you organize, markup, comment, and effectively present your models when using the new versions of Fathom 13, Arrow 10, Impulse 10, and xStream 3. In addition to the pre-existing rectangles and ellipses, you can now add diamonds, pentagons, hexagons, octagons, clouds, trian
Pause and Resume Lengthy Transient Simulations Using Checkpoint Files
Much can be done to reduce model run times, but it's a fact of life with transient simulations that some systems are just large and complex, need to cover longer spans of time, or have dynamics that can only be accurately captured with finer sectioning. In such cases, long run times can be unavoidable.Have you ever needed to pause a lengthy si
Sounds Dangerous – Analyzing Sound Power Level in AFT Arrow
As gases flow through pressure reducing devices, the pressure drops and the gas expands, experiencing irreversible energy losses. At these locations, the gas undergoes turbulent mixing and deflects off the pipe walls at high velocities. If the flow is sonically choked due to the restricting device, the flow must also pass through a standing shockwa