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Welcome to the Applied Flow Technology Blog.
Erin Onat

A Clever Way to Mitigate Waterhammer During a Valve Closure

One of the most common causes of waterhammer in pipelines is a valve closure. As the valve closes, the flowing liquid is forced to stop, resulting in a transfer of kinetic energy to potential energy, which ultimately causes a pressure increase. If this increase in pressure is large enough, extremely severe damage can result in the pipeline. Engineers frequently mitigate this waterhammer by selecting a valve that closes slowly enough to prevent the pressures from getting too high. However, a valve that closes too slowly can cause problems elsewhere in the pipeline or result in other undesirable outcomes in the process....
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Ben Keiser

Using Equivalent Lengths in AFT Fathom

One of the new features in AFT Fathom 9 was the ability to model equivalent lengths instead of K factors for various types of fittings. Since AFT Fathom's existence, the standard K factor loss models have been used to quantify the pressure losses across a fitting such as an elbow, a valve, etc.  One of the reasons why the K factor method is very useful is because it is broad and applicable to a wide range of different fittings.  However, the equivalent length method is also a way that engineers will typically quantify the losses through their fittings and they will...
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Ben Keiser

Overcoming New Heights - System Priming Before Siphon Effect Can Help

The process of sizing a pump for the application of priming a piping system as well as for normal operation is slightly more involved than if the system was already primed and the pump was to be sized for a liquid full system.  For a system priming application, the intermediate elevations at high points in a piping system are relevant in regard to the pump that is used.  If a pump is not able to generate enough head in order to overcome the high intermediate elevation points in a system, then the pump will provide no benefit to the system, even...
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Recent Comments
Geoff Stone
Such a system is most likely to experience column separation on pump trip. Therefore it may be necessary to install restriction or... Read More
Wednesday, 27 July 2016 13:07
Ben Keiser
Those are some great points Geoff and I absolutely agree that it would behoove the engineer to perform a proper waterhammer analys... Read More
Thursday, 28 July 2016 15:25
Ben Keiser
Hi Jose, Thank you for reading the blog and yes, you are correct in that if the static pressure drops below vapor pressure, then ... Read More
Wednesday, 14 March 2018 22:22
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Erin Onat

Calibrating Your Hydraulic Model with Multiple Data Sets

When evaluating the hydraulic behavior of aged pipelines and/or pipelines that are exposed to particularly corrosive or dirty fluids, building and running a hydraulic model is a great first step, but more engineering may be required. This is because, over time, residue in the pipeline fluid can buildup in the pipeline and essentially decrease the pipe inner diameter while increasing the roughness of the pipe’s inner surface. Corrosion can also change the roughness of the pipe’s inner surface. Engineers know that these changes due to buildup and corrosion in the pipes can significantly affect the hydraulics of the system, so while building a hydraulic model of the system is essential to evaluate its behavior, calibrating the model to account for these changes can be just as important in getting an accurate representation of your system. AFT Fathom and AFT Arrow offer a goal seeking module to assist with this calibration process with one data set of flow data. To understand how this can be done, visit Dylan’s blog. My blog here will take Dylan’s discussion one step further and discuss how AFT Fathom and AFT Arrow can be used to calibrate a hydraulic model with not just one but with multiple data sets using the GSC (Goal Seek and Control) module.

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Jeff Olsen

Seeing Double – Using Dual Y-Axis Graphs

Previously, we talked about the Graph Guide and how to create Stacked Graphs . Another way to see the interactions between parameters is to show them on one graph with dual Y-axes and a common X-axis scale. I am going to again start with the AFT Impulse model, ‘Pump Startup With Event Transient.imp’, which is installed in the Examples folder, and use the ‘One Pump Start With One Running’ scenario. In the previous blog, we used a Stacked Graph to examine the pressures and flows at two valves (J6 and J9), which opened during the simulation. This time, we will put...
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Ben Keiser

Databases 401 - Managing Databases

So by now, you should be about ready to graduate from my courses on Database Management and have become an expert on how to customize AFT software for your specific needs!  Databases 101 was the introductory course that walked you through the basics and flexibility available to you with relation to using databases in AFT software.  In Databases 201, we got slightly more technical as you learned how to create your own fluid database.  Things got more rigorous in Databases 301 where you learned how to create your own custom pipe material database. In our final course, Databases 401, you will...
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Jeff Olsen

Things Are Really Stacking Up – Creating Stacked Graphs

Using graphs that are stacked on top of each other is a great way to see the variation of several parameters at once and how one interacts with the others. There are several ways to create stacked graphs using the new graphing features in AFT applications, which I will cover here. I am going to start with the AFT Impulse model, ‘Pump Startup With Event Transient.imp’, which is installed in the Examples folder. I am going to use the ‘One Pump Start With One Running’ scenario. We will first compare the flow and pressure in the pipe path from the Supply...
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