Pipe Model

Size

The size section of the Pipe Model tab specifies the pipe geometry.

  • Pipe Material

    • User Specified - If selected, the geometry of the pipe must be directly specified.

    • Library Material - Many common pipe materials are included in the standard Pipe Material library. These and any other accessible library materials can be selected. When a library material is selected, the parameters defining the geometry cannot be modified.

  • Size - Select from a list of defined nominal sizes for the selected Pipe Material. Only available for library materials.

  • Type - Select from a list of defined types (classes/schedules) for the selected Pipe Material. Only available for library materials.

  • ID Reduction (Scaling) - Reduction in hydraulic diameter due to scaling can be accounted for by entering a percent reduction in this field. Zero represents no reduction.

Length

The Length is defined as the distance between the two connecting junctions. This length has no relationship to the visual length of the pipe drawn on the Workspace.

Note: In contrast with other AFT products, xStream does not contain the Zero-Length Connector (ZLC) option at this time.

Friction Model

Multiple friction data sets can be compiled for each library pipe material. These different data sets are then made available in the Data Set drop down list. For AFT standard materials, the friction data set is generally "Standard."

The Friction Model can be modified for any individual pipe, and the default friction model can be set in Parameter Options. The Friction Model for a library material can be modified by selecting the User Specified radio button in Data Set, and must be directly specified for User Specified materials.

  • Absolute roughness (default) - Absolute average roughness height. Values of pipe roughness can be found in many pipe handbooks or from manufacturer's data.

  • Relative roughness - Relative roughness is the absolute roughness divided by the pipe diameter.

  • Hydraulically smooth - Hydraulically smooth implies that roughness is negligible. This is not the same as frictionless.

  • Explicit Friction Factor - Friction factor for the pipe, you can enter the value explicitly.

  • Frictionless - For troubleshooting purposes, it is occasionally useful to model a pipe as having no friction. There are limitations to where such a pipe can be located in your model.

For detailed information on how these Friction Models are defined, see Pressure Drop in Pipes - Detailed Discussion.