Pressure Pipe General Tab
The General tab for pressure pipes is organized into the following groups: • Pipe - General pipe data.
• Initial Status - Specify whether the pipe is initially open or closed.
• Invert Elevations - Displays elevations of the pipe inverts at the upstream (From node) and downstream (To node) end.
• User-Defined Length - Specify whether the pipe length is calculated automatically or user-defined. • Nodes - Displays the nodes at the upstream and downstream ends of the pipe.
• Hydraulic Results - Displays calculated hydraulic data. For further details, refer to the topics describing each section.
Pipe Section
In this section you enter in all of the pipe general characteristics:
• Label - Unique name referencing the pipe in reports, error messages, and tables.
• Material - Pipe material, with its associated roughness value, selected from the Material Library. • Diameter - Diameter of the pipe.
• Roughness Coefficient - Pipe roughness coefficient or value associated with the roughness method selected during the project setup (Manning’s n, Hazen-Williams C, or Darcy-Weisbach roughness height) for the selected material. You can keep the roughness value associated with the selected material, as defined in the material library, or override the roughness value for that specific pipe. • Minor Loss Coefficient - Coefficient K used in the minor loss equation, as defined in the Minor
Losses section in Appendix B. This is the equation most commonly used for determining the headloss
in a fitting, valve, meter, or other localized component.
• Check Valve - When this box is checked, flow can only travel from the From Node to the To Node in a pressure pipe.
By clicking the ellipsis (...) button located next to the Material you can access the engineering library to create and customize materials.
By clicking the ellipses (…) button on the Minor Loss Coefficient field, you can access the Minor Loss elements and generate composite minor loss coefficients to be applied to the pressure pipe. Set the minor loss coefficient value to 0.0 if there is no minor loss in the pipe.
Minor Loss Elements
Pressure pipes can have an unlimited number of minor loss elements associated with them. This program provides an easy-to-use table for editing these minor losses. The minor loss table consists of four columns: • Quantity - The number of minor losses of the same type to be added to the composite minor loss for
the pipe.
• Minor Loss - The type of minor loss element.
• K Total - The total minor loss coefficient for the row. It is the Quantity multiplied by the K Each. The Minor Loss Elements dialog also has three command buttons:
• Insert - Insert a row in the table.
• Duplicate - Create a new row in the table with the same values as the selected row. • Delete - Delete the selected row of the table.
The Minor Loss Elements dialog is accessed by clicking the ellipsis (…) button next to the Minor Loss Coefficient choice list on the Pressure Pipe Editor.
Initial Status Section
The initial status of the pipe can be either Open or Closed. The status can possibly change when calculations are performed based on the presence of controls for that pipe.
In Steady State Analysis mode, the Initial Status is used as the permanent status. However, it can be overruled by the presence of controls, if the Use Controls in Steady-State Analysis check box in the Calculation Options dialog is checked. The Calculation Options dialog is accessed by clicking the GO button in the main view to display the Calculation tab of the Scenario Editor, and then clicking the Options button.
Invert Elevations Section
The From Node and To Node Elevations of the pressure pipe can be entered and viewed here. . If Set Invert to Upstream/Downstream Structure box is not checked, you can set the From and To elevations in this section. Otherwise, the program will compute the pipe’s From and To elevations using the upstream/downstream gravity structure’s sump elevation.
Disabled elevations are defined at the connecting node structure. Only inverts that are connecting to gravity node structures such as wet wells or outlets can be edited. Inverts connecting to pressure elements such as pressure junctions and pumps cannot be edited.
User-Defined Length Section
If the User-Defined Length box is checked, you can enter a pipe length. Otherwise, the program will compute a pipe length from node center to node center, accounting for bends if there are any. Creating user-defined lengths is useful for drawing quick schematics to accelerate your design process.
Nodes Section
Displays the nodes that are upstream (From node) and downstream (To node) of the pipe. If the flow is traveling from the From Node to the To Node then the flow value will positive. If flow is traveling from the To Node to the From Node it will be negative. You can reverse the From Node and the To Node by clicking the Reverse button.
Hydraulic Results Section
This section reports the following hydraulic results: • Pressure Flow - Calculated total flow in the pipe. • Velocity - Calculated velocity in the pipe.
• Headloss Gradient - Headloss in the pipe represented as a slope, or gradient. • Pressure Pipe Headloss - Loss of energy in the pipe due to friction and minor losses.
• Control Status - Open or closed status of the pipe. Open means that flow occurs in the pipe and closed means that there is no flow.