AFT Blog
The Opposite of Good Vibrations - Evaluating FIV, AIV, FIP Guidelines from AFT Fathom and AFT Arrow
Learn how to use AFT Fathom and AFT Arrow to help calculate the Likelihood of Failure (LOF) for Flow Induced Vibration (FIV), Acoustic Induced Vibration (AIV), and Flow Induced Pulsation (FIP) in accordance with Energy Institute Guidelines to avoid v...
It's a Pump! It's a Turbine! It's a Pump as Turbine!
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 betwe...
What Is Transient Analysis?
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! ...
Know Your Pump & System Curves - Part 3
In the final "Know Your Pump & System Curves" blog series, I am going to discuss the complexities behind pump vs. system curves for systems with pumps in series and parallel configurations. Multiple pumps in series configurations are relatively s...
Digital Twin – Identical or Fraternal?
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 buz...
That Valve’s Got Character – Applying Pre-defined Characteristic Curves
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 d...
It was an honor to visit our friends in Beijing, China to provide our Channel Partner, AECsoft Engineering Software (AECSOFT), two days of complimentary workshops. During these workshops, attendees had a hands-on experience with AFT Software as well the opportunity to discuss relevant hydraulic topics. Each attendee also received a 15-day free trial license to review topics discussed in the workshop. The first workshop, held August 21-22, hosted 65 attendees from twenty-nine companies. The workshop focused heavily on technical orientation to the AFT software. The second workshop, held August 24-25, was dedicated exclusively to the biggest state...
For several users of AFT software, it goes pretty predictably: first you place a pressure junction, then maybe a pump, then some sources of pressure drop including valves and heat exchangers, and then the model is finished off with another pressure junction. Of course, this is greatly oversimplifying the process and the vast array of systems that are modeled with AFT software, but here’s my point: most users are more familiar with modeling open systems that include individual pressure junctions located both upstream and downstream of the system. But what about modeling closed systems? The truth is that modeling closed systems...
Computers currently cannot think like an engineer. That is probably a good thing, but sometimes it can get us in trouble. Many of us rely on computers daily not just for fun or leisure, but for our livelihoods. They connect us in ways previous generations never thought possible and augment our mental abilities especially in terms of performing complex calculations and modeling intricate systems. Knowing this, it is important to remember that no matter how slick the user interface or how advanced the underlying code is, a computer program is only going to take what you give and process it with...
There are many (six!) ways to define a pump transient event in AFT Impulse. This gives you great flexibility in creating a model that behaves the way you want it to. One thing true for all pumps is that they must be started at least once. Pump startups often cause significant transient effects on the system so you may wish to model this with AFT Impulse. Even narrowing your pump transient down to a startup, there are still four models left to choose from: Without InertiaStartup With Inertia and No Back Flow or Reverse SpeedStartup With Inertia - Four Quadrant, Known...
Unknown to me, a few weeks ago I was sitting across from a Brazilian hydroelectric engineer on an airplane flying across Brazil. His name was Roberto and he did not speak English. I myself was learning the basic Portuguese phrases but that was the extent of my language skills. I was traveling with my son (an engineering student himself) who was spending the southern winter (i.e., northern summer) working in São Paulo, Brazil. My son had learned to speak Portuguese amazingly well and struck up a conversation with Roberto. That was when he found out Roberto was a civil engineer who used to work in hydroelectric power.
To define any transient event in AFT Impulse or AFT Fathom XTS the application must know when it begins. To do so, the user should know how time and event logic is approached in AFT’s transient solvers. In this article, we will discuss the three different time bases used in the applications, the selection of a single or repeating event, and the many possible triggering events that can start the user defined transient. The user defines these items in the Initiation of Transient section of the junction’s Transient tab. The requirements for each junction can vary, but the general approach applies...
In February I reached a new low. Up until that point, my lowest point happened as a child in my home state of California. That was when my father took me through Death Valley - elevation 282 ft (86 m) below sea level.
But this was different. I was not going to the lowest spot in North or South America (Death Valley). I was going to the lowest spot in the entire world. I was on my way to the Dead Sea. Located on the border between Israel and Jordan (see my personal photos below), the Dead Sea is at an elevation of 1412 ft (431 m) below sea level - and getting lower all the time as it further evaporates.