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# AFT Product Tips

Welcome to the Applied Flow Technology Blog.

## What Does “Head (HGL)” Mean for Submerged Pumps and Exit Pressures?

In AFT Fathom and AFT Impulse , it is possible to model a submerged pump where a short and possibly frictionless suction pipe for the pump’s inlet does not need to be modeled.  When modeling a submerged pump, there are two options available for specifying the system inlet boundary condition at the pump suction.  As shown in Figure 1 below, the Submerged Pump’s Suction Pressure can either be specified as “Head (HGL)” or “Pressure”.   Modeling a submerged pump is not the only time where the “Head (HGL)” or “Pressure” choices will arise.  If an Exit Valve (i.e., a valve that...
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## Know Your Pump and System Curves - Part 1

AFT Fathom can easily generate a pump and system curve for your piping system.  Creating a pump and system curve for a simple system with a single flow path and no control features is an easy and typically well-understood process.  However, as piping systems are quite complicated with lots of branch points, control features, and dynamic interactions, creating a useful system curve can quickly become a common source of confusion.  This three-part blog series is going to help clarify concepts regarding pump and system curves to better understand them.   This Part 1 blog will discuss the basics of what pump...
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## When Should You Use Variable Pipe Resistance?

Have you ever finished running an AFT Impulse model and then received the following Warning message shown in Figure 1 and then wondered what it means? During a waterhammer analysis, the flowrates are constantly changing all throughout the system, therefore, the velocities and Reynold's numbers are also constantly changing.  The friction factors will also be constantly changing during the transient.  By default, AFT Impulse will use the friction factors that are obtained during the steady-state analysis and then use the same friction factors during the transient and they will be assumed to remain constant. Since it is possible for the flowrates...
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## Combining Pipes in AFT Impulse to Decrease Model Run Times: How Resistance Curves Are Merged into Pipes to Increase Pipe Section Length

They say that time is of the essence, and as engineers, that couldn’t ring truer! AFT pipe flow software is there to help engineers save time by more safely, efficiently, and rapidly designing and analyzing their piping systems. AFT Impulse , Applied Flow Technology’s waterhammer tool, helps engineers analyze transient incompressible flow behavior that can cause potentially detrimental pressure surges. It uses the Method of Characteristics, which requires the pipes to be sectioned using a Characteristic Grid. In this Characteristic Grid, all of the pipes are broken into an integer number of section lengths, and pressure waves are assumed to propagate...
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Hi Erin, This method really helps to reduce the runtime of model but in some model like the one which i have with me has few small... Read More
Friday, 05 May 2017 06:37
Hi Devendra, Thank you very much for your comment, and I'm very glad that you have found this blog useful. There is no way to ig... Read More
Monday, 08 May 2017 17:25
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## Getting the Perfect Picture – Graph Formatting Options

Previously, we talked about the Graph Guide , creating Stacked graphs and Dual-Y graphs, and visualizing the results using Animated graphs. This final installment will focus on the various ways to format graphs so they are exactly how you want them to look. In general, there are several ways to set the formatting for the various parts and regions of a graph. I will start with the model we made in the previous blog – the AFT Impulse model, ‘Pump Startup With Event Transient.imp’, which is installed in the Examples folder. Many of the formatting options are gathered together on the...
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## That was EASY! Quickly Change Pipe and Junction Input Data into AFT models using Excel Change Data

Users and potential users of AFT software frequently ask how they can expedite the model input process so that they can get the results they need as rapidly as they need. I’m pleased to report that AFT software has an abundance of features that make the model input process tremendously efficient: global pipe and junction editing, copying input data from other pipes and junctions, and finally, importing data using the Excel Change Data parameters spreadsheet (which is what we are discussing in this blog). The Excel Change Data feature works by importing data from an Excel spreadsheet populated according to a...
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Nice! Thanks for the links to the files -- made the post 100% more useful.
Tuesday, 25 October 2016 17:49
Wednesday, 26 October 2016 18:02
That's Very well explained. I'm expecting something over "GIS Shapefile Import".
Friday, 24 March 2017 07:43
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## The World in Motion - Understanding Results Through Animated Graphs

Previously, we talked abo ut the Graph Guide and how to create Stacked Graphs and Dual-Y graphs. With AFT Impulse and with AFT Fathom’s XTS module, a great way to see how parameters ch ange over time is through animated graphs. For the purpose of continuity, 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 blogs, we used a Stacked Graph and a Dual-Y Axis Graph to examine the pressures and flows at two...
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