Resources 2025

Databases 301 - Those Are Some Nice Pipes!

Written by Ben Keiser | Apr 28, 2016 4:00:00 AM

In continuation to my past two blogs regarding how AFT's and greatly enhance flexibility and efficiency, the power that stems from creating customized pipe material databases is no different!

AFT's Software Products incorporate several different pipe materials that you can work with such as steel, stainless steel, ductile iron, copper, PVC, HDPE, etc.  However, should you be worried if you do not see a pipe material in our list of available pipe materials that you need to work with???  Not at all!!  Easily create your own custom pipe material and it will be added to your local user database for you to use forever and ever!

Whether you are using AFT Fathom, AFT Arrow, or , the process is the same.  Start by opening the AFT product you are using and then go to the Database menu and select the "Pipe Material Database".  This will open the Pipe Material Database window as seen in Figure 1 below where you will create your new pipe material by simply clicking the "New Material" button.

 After clicking the "New Material" button, you will be prompted to enter some basic information into the "Add Pipe Material Data" window such as the pipe material name, nominal size, inner diameter, wall thickness, friction model, etc.  As you can see in Figure 2 below, I have created a new pipe material called "Gold Pipe" which is a very nice material as I am sure you can imagine!  Only the elite of pipe flow analysts would attempt to work with such a prestigeous pipe material.

A couple things I would like to point out in regards to the material type and the friction model.  The "Material Type" is simply the desired schedule for that nominal size and you can name that whatever you like.  For the Friction Model, you need to of course, choose a specific friction model.  You also have to give the friction model a description.  Why do you need to give the friction model a description if it is pretty self-explanitory?  Well, if you are interested in defining multiple "standard" friction models and they are using the same "Friction Model" (i.e., Absolute Roughness, Explicit Friction Factor, etc.), then you may want to distinguish things better that have the same Friction Model.

It absolutely is possible to define additional Material Types and Friction Models and I will discuss that shortly.

The wall thickness is option because it would only be required for heat transfer calculations, as the wall thickness does not affect pressure drop calculations.  However, if you ever plan on bringing your AFT Fathom model into AFT Impulse and you have built a custom pipe material data set, the pipe wall thickness is an important input parameter that allows the determination of the wavespeed for the waterhammer calculations.  Therefore, you may want to enter the wall thickness from the get-go in AFT Fathom just in case.

After you click OK to accept the updates for the new pipe material, you will then see a new pipe material, type, and nominal size that has been created in the list of available pipe materials as shown in Figure 3.  Here you can see all the information that was specified for nominal size, type, inner diameter, friction model, etc.

If you would like to add more types for the 10 inch nominal size, simply select the nominal size level (i.e., 10 inch) and then click the "New Type" button.  Specify a new Material Type, Inner Diameter, and Wall Thickness like in Figure 4.

Figure 5 shows that there are now two schedule types that can be used for the 10 inch nominal size for the new Gold Pipe Material.

Now, let me come back to how you can define additional "standard" friction models.  The main thing that I would recommend is that if you would like the new friction models to apply to all sizes and types for your new material, then be sure that you select the Material Level for your new pipe material and add the additional friction models at the Material Level.  Otherwise, they will only apply to the specific nominal size or type if entered at the size and type levels.

So now I'm going to select the "Gold Pipe Material" level and then under the "Friction Data Sets" on the right, I am going to click on "New Data Set".  Then you can specify the description for your new Friction Data Set and enter a value like in Figure 6.  Note that you can define as many "standard" frictional data sets as you like and this includes multiple frictional sets for the same frictional model (i.e., Very Smooth Absolute Roughness = 0.00001 inches and Very Rough Absolute Roughness = 0.1 inches).  This is why you would add more to the description field.

Figure 7 shows that there are now two "standard" Frictional Data Sets that I can use and since I specified them both at the Material Level, then they will be available to use for ALL nominal sizes and all material types for the Gold Pipe Material data set.

You can also specify insulation datasets if you know that there is already insulation included with your pipe material (or you can specify an insulation data set separately).  You can also click on the "Pipe Thermophysical Properties" tab and then you can click the "Specify Properties" button.  By doing that, you can then enter the thermal conductivity and bulk modulus of the pipe as functions of temperature as well as a density for the pipe.  Again, in order for the pipe thermophysical properties to apply for ALL sizes and types for a material, enter these properties at the material level.

In AFT Fathom and AFT Arrow, the bulk modululs for the pipe material is an optional input and is actually not even used in AFT Fathom or AFT Arrow.  However, if you want to use this pipe material data set later with AFT Impulse, then in that case, the bulk modulus for the pipe is also an important input parameter for the wavespeed just like the wall thickness parameter is.  So entering the optional input in AFT Fathom and AFT Arrow will save you some time when using this data in AFT Impulse, that way you do not have to edit your existing database later.

After all is said and done and your new pipe material has been created, you can easily access it from the Pipe Material drop-down menu within the Pipe Properties window and then select the desired nominal size, type, and friction model as shown in Figure 8.

Well, that's all there is to it!  Enjoy those nice pipes!