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...
"Who has extra time?", you ask. Well, at least for today, we all do. Because today is the day on which a "leap second" will be added - according to this article in TIME magazine.
I like cool new features in software. And I am especially proud of those in the upcoming AFT Fathom 9. We expect this new version to be available in the next two months. Below I will touch on some of the new features I think will be of most interest to you.
Well that depends on how optimistic you are, but either way you can model partially full pipes with AFT Impulse! This means partially full along the axial direction, as opposed to partially full along the radial direction. This function only works for pipes that have a slope, and when the pipe is partially full it drains from the end with the higher elevation. Pipes which contain vacuum breaker valves, exit valves, spray discharges, or assigned pressures at the outlet can drain or fill during the transient. This draining or filling is limited to the specified pipe. AFT Impulse will not model...
When dealing with a compressible gas system, heat transfer and thermal effects are very important to account for. When a gas is flowing down a pipeline, it will cool down as the gas expands due to the frictional pressure drop. Many would say that adiabatic or isothermal conditions will bracket the potential flow rates that are possible for a constant pressure drop in a pipe. However, this is not the case. If a gas is cooled or heated as it flows down the pipeline, the flow rates that can result for a given pressure drop can actually be outside the “bounds”...
In AFT Arrow, there are three types of fluids that can be modeled: AFT Standard, ASME Steam, and Chempak. The focus of this article will be on how to use the Chempak Database with AFT Arrow in order to perform dynamic mixing calculations. But first, I would like to briefly introduce each of the three types of fluids that can be modeled in AFT Arrow. The gases in the AFT Standard fluid list are included with the standard AFT Arrow software. Various equation of state models are available including Ideal Gas, Constant Z, Three Parameter, and Redlich-Kwong. There are also multiple...
Engineers often think in terms of extremes in order to add perspective to a problem. So I will engage in some extreme thinking here to help understand why engineers are by and large a very dissatisfied group of people.
Many engineers are familiar with gas accumulators and their ability to aid in surge suppression modeled in AFT Impulse, but what about liquid accumulators? Liquid accumulators are different from gas accumulators in that they are assumed to be liquid full and do not have any gas that can compress and expand in order to dampen pressure spikes caused by water hammer. Liquid accumulators change the system response to pressure spikes, but they operate differently than gas accumulators. There are only three required input parameters for liquid accumulators; Elevation, Elasticity, and Initial Volume. Figure 1: Liquid Accumulator Properties Window Initial Volume is...