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.
Vacuum breaker and air valves are useful tools in the industry for protecting pipelines against vacuum or near vacuum conditions. High points in the pipe can be susceptible to these low-pressure conditions during surge events, as pressure waves moving through the system cause a sudden pressure upsurge or downsurge. AFT Impulse can help engineers t
One of the many powerful features in AFT Impulse is the ability to calculate transient forces during a waterhammer/surge event (See "Evaluating Dynamic Loads in Piping Systems Caused by Waterhammer" white paper). The resulting transient forces can be exported into a pipe stress analysis software. Pipe stress analysis care about what the trans
If you have worked with Non-Newtonian fluids or low velocity systems in AFT Fathom or AFT Impulse before, then it is likely that you have worked with the Adjusted Turbulent K Factor (ATKF) method before. The ATKF method can be used to adjust K factor data developed for turbulent flow conditions to better predict loss in the laminar f
It was not intentional. The Trifecta I mean. It just sort of happened organically. But now that I have completed it, I think it is kind of cool.There are three Space Shuttles that have flown into space and are now in American museums:Discovery - in the Smithsonian Air & Space Museum in Chantilly, Virginia (near Washington D.C. f
What booth and why does it have waterhammer? Come find out! In a few weeks, AFT and yours truly will be at the Turbomachinery and Pump Symposia (TPS) in Houston – September 10-12 to be precise. We will have a booth (#2824 for those who are coming). And we will have waterhammer. Not just waterhammer software. We have that every year and, as in previ
Almost every piping system has valves, and an accurate solution requires accurate valve losses. For incompressible systems, this is relatively straightforward. What happens when we introduce the complexities of compressible flow? Valve Sizing Equation in Incompressible Flow In liquid flow - like that calculated by AFT Fathom or AFT Im
Any time a rapid transient occurs in a piping system, there is a chance for unexpected surge to impact the system. Though system shutdowns account for many surge events, pump startups can cause water hammer as well. For this blog I am going to cover the basics of setting up pump and valve transients for the startup case in AFT Impulse 7, as well as
Happy New Year and Happy New Decade to all of you around the globe! As engineers, our society depends on us to help solve problems and make everyone's lives better. To provide power, water and heat are the basics. To provide transportation and communication are now critical technologies. Plus lots more.The unfortunate truth is that in solving the p
Like most of you, I have no expert advice to give related to the current worldwide pandemic caused by COVID-19 – also known as the Coronavirus. Thus, I won't presume to offer advice or wisdom on that topic. But everyone is talking about, reacting to and being affected by the pandemic. It seems almost insensitive to not acknowledge that.As the Presi
With new versions of Fathom, Arrow, and Impulse being released, we've been taking time to highlight some of the new features that have been added in. Recently, we've looked at multi-scenario pump vs. system curves, along with more general overview of our new features. In this blog, we'll look at one of my favorites, the new Scenario Comparison tool
Over the past few months, I've gotten to help Impulse users from around the world with their models. One of the most common problems I run into while helping them is runtime. A good rule of thumb I try to use is that most Impulse models should take less than 10 minutes to run, and none should take more than a half hour to run. Longer runtimes mean
In June 2020, AFT's Reinaldo Pinto presented the webinar Calculating Transient Forces for Pipe Stress Analysis. The webinar focused on generating unbalanced forces due to surge in AFT Impulse and exporting them to CAESAR-II. During the webinar, 28 questions were asked. Below are the responses. Download the presentation: www.aft.com/w
In early 2020, AFT users gave us valuable feedback via our annual survey. We read and absorbed requests for additional capabilities our software doesn't yet have, as well as capabilities the software already has and users may not be aware of. Customers praised us for the prompt high-level of support our team provides, and they let us
When I wrote AFT Impulse 1 back in 1996, I slipped in an undocumented feature to make it capable of modeling the first waterhammer project I did in industry. Since then, this feature had a secret (i.e., undocumented) way of being enabled. AFT Impulse 8 will be released any day, and we have finally made this feature accessible to all. In the User Op
While thinking in terms of pressure is often intuitive for engineers, thinking in terms of head can be more challenging. You may be surprised by the number of cases and questions that come to the support team here at AFT about the basic definition of head, and how it relates to hydraulic modeling. Let's get back to the basics with how head is defi
Valves are often oversimplified during modeling. Understandably, defining a valve with its range of Cv at various open percentages requires much more information than an engineer may have during the initial design phase. However, just like handbook data, heuristics, and correlations, valves too can be reasonably approximated using their common char
As the original developer of AFT Arrow, I consider it as one of my babies. This month it is all grown up and now 25 years old. Back in March we came out with the latest new version AFT Arrow 8 – just as the COVID-19 crisis was emerging.Those who have taken an AFT Arrow seminar which I have taught (at least fifty classes and counting!) have likely h
Flow going backwards through a pump? Then the pump starts rotating in reverse? Where the heck is the check valve to stop the flow? These are all great questions (which I will answer later in this article).Theodore von Kármán and Robert Knapp were working on these questions in the early 1930's. Most engineering students encounter von Kármán in their
When I was a child, I was jealous of twins. I thought how cool it would be to have a twin. I had twin cousins a few years older than I was that I saw on a frequent basis. I always got them confused. Which one was Roger, and which one was Ronny?A buzzword floating around recently is "digital twin". Sounds cool. What is it? According to a webinar by
Non-Newtonian fluids are something almost every elementary school student is familiar with. Mixing cornstarch and water to create a liquid that acts as a solid is an experiment which has captured the attention of children (and adults) for generations. The Discovery Channel show Mythbusters even showed Adam Savage walking across a tub of cornstarch
My High School Physics Teacher When I was in high school (four decades ago!) I had an awesome physics teacher in my junior year, Mr. Kindred. His class was a key influence in my decision to pursue a career in mechanical engineering.I recall Mr. Kindred discussing the future of fusion power and commenting, as was common at that time, that "fusion p
Have you ever been working on an interesting project where you get into the zone by picking up so much momentum in the work you are doing? But then, all of a sudden you hit a brick wall in your progress and cannot help but feel the pain of all that momentum coming to a screeching halt? You are not alone, in fact, fluids experience something ve
Trying to run a model and running into convergence errors? Here are a few common tips to help with model convergence for AFT Fathom, AFT Arrow, and the steady state modes for AFT Impulse and AFT xStream. Though these tips will not work for all models, they have helped with many of the steady state convergence cases that have come through the AFT s
You're tasked to perform a transient analysis of a piping system and it would be really helpful if there was a good software tool out there to help you. Well, you've come to the right place because AFT has great solutions! But our first question is, "What kind of transient analysis are you trying to do?" You might s
Veteran AFT software users are familiar with heritage products like AFT SteamCalc and AFT Chempak Viewer. Some have wondered where these products went. Although licenses to these products are no longer sold, these viewers are now integrated into the main applications for each of AFT's main products: AFT Fathom, AFT Arrow, AFT Impulse, and AFT
You've built a model, verified all of the inputs, and now you have results, but how are you going to organize and present these results? Here is a quick guide to some of the customization available in AFT software for displaying output and exporting your data using the Output, Visual Report, and Graph Results windows. The screenshots and examples f
Let's face it, specifying every pipe size, length, elevation, pump curve and component loss in a hydraulic model can be tedious. While essential to fully defining a system, often there is avoidable redundancy during model specification. The Global Edit feature helps to ease this tedium and redundant specification by mass updating overlapping parame
As you know, AFT is a developer of a world leading waterhammer simulation tool in AFT Impulse. We regularly get asked for waterhammer guidance by engineers tasked with building piping systems. While there are some excellent waterhammer resources available, there is not much decision-making content from non-commercial authoritative organizations. Th
New versions of AFT Fathom, AFT Arrow, and AFT Impulse are being released in the upcoming months. This round of releases focuses on major interface changes which will improve user efficiency. Check out these new features and improvements that will be in Fathom 12, Arrow 9 and Impulse 9. Analysis SetupTo make the modelling process simpler
AFT has some good news for engineers who analyze gas transients. AFT is introducing the new AFT Arrow Extended Time Simulation (XTS) Add-on Module to help engineers better calculate compressed gas flow rate changes in piping systems. This time-based simulation software allows engineers who are designing or troubleshooting industrial
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
Pump manufacturers often supply performance curves at a specified speed. While this is useful when the pump only runs at that rated speed, performance changes when the pump has a Variable Frequency Drive (VFD). A VFD changes the shaft speed, which, in turn, changes the performance curves. If the manufacturer only supplied a curve at a sin
AFT strives to make our interface intuitive and user-friendly, but we know that pipe flow modeling can be complex. That's why the AFT team have worked to put together the AFT documentation portal, a new centralized place to find all of our help resources for AFT Fathom, AFT Arrow, AFT Impulse, and AFT xStream. Here's a quick summary of what you can
Wow, have things changed a lot in the last two months! Russia's unprovoked attack on Ukraine in February has literally changed the world. Our hearts and prayers go out to the Ukrainian people who are experiencing unimaginable suffering. Tens of thousands of people have died and many more have had their lives upended. Now two months later Sweden and
Having some trouble getting your modelling under control? This blog will discuss some tips on how to properly use a control valve in AFT Fathom and how to interpret some common control valve warnings. For simplicity this blog will primarily discuss control valves in the context of AFT Fathom. However, the concepts discussed in this blog also apply
Pumps and turbines may serve opposite purposes, but fundamentally, they operate under the same principles. Both pieces of equipment convert between usable work and fluid energy, and both often use an impeller to make the conversion.Differences between the two pieces of equipment quickly start to appear as they are examined with more detail. A pump
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
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
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
Last month I presented a technical paper that was both the easiest and the hardest paper I have written. The paper was on a waterhammer accident in 2016 at an alumina refinery which caused a slurry pump to catastrophically fail. The pump casing exploded and the hot, caustic slurry it was pumping sprayed onto a technician nearby resulting in severe
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
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
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
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
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