Tutorial 2: Piping System

This exercise will walk the user through building a portion of the water circuit of a piping system. The user will learn how to:

  • Edit chamber properties
  • Edit element properties
  • Check the model
  • Run the model
  • Post-process the model
  • Chamber Types: Plenum, Momentum
  • Element Types: Junctions, Incompressible Tube, Bends, Transition, Nozzle
  • Fluid: Liquid Water

Step 1: Examine geometry and create plan

  1. The user will be creating a model of a water piping circuit shown in figure 1.01.

Figure 1.01: Water piping system

  1. The model begins with long runs of straight piping connected by 90-degree bends. It then splits in two directions and transitions into smaller diameter pipes, which then feed four spray nozzles.
  2. To model this piping system, the user will primarily be making use of tube, bend, and junction elements.

Step 2: Load IGES file

  1. Go to File → Load IGES File
  2. Browse to IGES location and select open (water_piping.igs)

Figure 1.02: Loaded IGES on default background

Step 3: Building Model

  1. Plan model setup based on what is known about the geometry

Figure 1.03: Sketch/Outline of model

  1. Drag and drop Boundary Plenum chambers at the inlet and outlet locations from Figure 1.01
    1. Pressing and holding “Shift” while dragging chambers and elements enables snapping to IGES vertices for easier placement (Figure 1.04)
    2. Additionally the translate (right click chamber/element → translate) option and manually editing the coordinates (Property Editor → Location), can be used to assist in placing chambers and elements in the right location
  2. Use to adjust symbol and text size

Figure 1.04: Snapping to IGES vertices

  1. Click and drag non boundary momentum chambers to the locations (blue circles) in Figure 1.03
  2. Set the inlet Plenum to a Static Pressure of 24.7 psi and Relative Total Temperature of 70 F
    • Set “Fluid Type” to “Single Liquid Species” and select “Water (L)” under “Single Liquid Species”
  3. Set the outlet Plenums to a Static Pressure of 14.7 psi and Relative Total Temperature of 70 F
    • Set “Fluid Type” to “Single Liquid Species” and select “Water (L)” under “Single Liquid Species”
  4. Click and drag Incompressible T-Junction elements to the pipe connection locations in Figure 1.05

Figure 1.05: T-Junction element locations

  1. For the piping leading up to the T-connection, use Incompressible Tube elements to connect the straight sections of pipe and incompressible Standard Circular Bend elements for the bends as shown in Figure 1.03
  2. For the tube elements, use the lengths shown in Figure 1.06.
    1. Set the number of stations to 10, check “Specified Diameter” under “Cross-Section Shape” and input a diameter of 2.07 in
    2. Under Segment Data, set Roughness to 0.0018 in and check “Adiabatic” for “Station Heat Transfer”

Figure 1.06: Tube Element locations

  1. For the Bend elements, set Bend Angle to 90 degrees, Bend Radius to 3.105 in, Diameter to 2.07 in, and Roughness to 0.0018 in
  2. After the T-Junction, place an Incompressible Conical Transition element, an Incompressible Tube element, followed by another Incompressible T-Junction as shown in Figure 1.07

Figure 1.07: Post T-Junction model set-up

  1. For the Conical Transition Element set Contraction K Loss to 0.06, Length to 0.166 in, Inlet Diameter to 2.07 in, and Exit Diameter to 1.5 in
  2. For the T-Junction Element set “Angle Between Arm 1 & 2” to 90 degrees, “Through Pipe Diameter” to 2.07 in, and “Branch Diameter” to 2.07 in
  3. For the Incompressible Tube element set Length to 6.10 in
    1. Set the number of stations to 10, check “Specified Diameter” under “Cross-Section Shape” and input a diameter of 1.5 in
    2. Under Segment Data, set Roughness to 0.0018 in and check “Adiabatic” for “Station Heat Transfer”

  1. Plan to set up the spray nozzle as shown in Figure 1.08

Figure 1.08: Nozzle model set-up

  1. Place the momentum chambers (blue circles) and connect them with Tube, Bend, and Liquid Nozzle elements as shown on figure 1.08
  2. For the first Bend Element use an incompressible Circular Mitre subtype and set Bend Angle to 90 degrees, Diameter to 0.81 in, and Roughness to 0.0018 in
  3. For the first Incompressible Tube element set Length to 4.32 in
    1. Set the number of stations to 10, check “Specified Diameter” under “Cross-Section Shape” and input a diameter of 0.81 in
    2. Under Segment Data, set Roughness to 0.0018 in and check “Adiabatic” for “Station Heat Transfer”
  4. For the second Bend element use a Incompressible Standard Circular subtype and set Bend Angle to 90 degrees, Bend Radius to 1.215 in, Diameter to 0.81in, and Roughness to 0.0018 in
  5. For the second Incompressible Tube element set Length to 30 in
    1. Set the number of stations to 10, check “Specified Diameter” under “Cross-Section Shape” and input a diameter of 0.81 in
    2. Under Segment Data, set Roughness to 0.0018 in and check “Adiabatic” for “Station Heat Transfer”
  6. For the last element in the spray nozzle, click and drag an Incompressible Liquid Nozzle element
    1. Set Flow Number to 678
    2. Set Reference Specific Gravity to 1
  7. For the T-Junction Element set “Angle Between Arm 1 & 2” to 90 degrees, “Through Pipe Diameter” to 1.5 in, and “Branch Diameter” to 0.81 in
  8. At this point, since this is a symmetrical mode, it is possible to copy and paste the elements, along with their inputs, from one side of the model to the other (Figure 1.09)
    1. One method of doing this is by copying an entire branch of chambers and elements using “Shift” to select multiple entities and “Ctrl+C” and click at the desired location to copy and paste, followed by the use of rotate and translate to align with the IGES
    2. Additionally, placing momentum chambers and then individually copying elements one at a time is also an option (this may be easier to align with the IGES)

Figure 1.09: Copying elements with inputs due to model symmetry

  1. Set up the remaining portion of the tubing as shown in Figure 1.10

Figure 1.10: Remaining piping set-up

  1. Place momentum chambers as shown (blue circles) in Figure 1.10 and connect them with Tube and Bend elements
  2. Place Incompressible Tube elements at the straight pipe locations. For the long tube use a length of 36.36 in and for the two shorter tubes use a length of 14.15 in
    1. Set the number of stations to 10, check “Specified Diameter” under “Cross-Section Shape” and input a diameter of 1.5 in
    2. Under Segment Data, set Roughness to 0.0018 in and check “Adiabatic” for “Station Heat Transfer”
  3. Place Incompressible Standard Circular Bend elements at the bends and set Bend Angle to 90 degrees, Bend Radius to 4 in, Diameter to 1.5 in, and Roughness to 0.0018 in
  4. Copy and paste the new elements, along with their inputs, from one side of the model to the other (Figure 1.11)

Figure 1.11: Copy new elements to other side of model

  1. Use the existing spray nozzle set-up to copy and paste the elements, along with their inputs to the remaining nozzles (Figure 1.12) and connect them to the T-Junction elements created earlier

Figure 1.12: Copy existing spray nozzle set-up

  1. To cap the model, drag and drop a boundary plenum at both non-nozzle ends, and use a “Blank End” element to connect the plenum to the T-Junction element as shown on Figure 1.13
    • Set boundary plenums the same as the other outlet plenums

Figure 1.13: Use Blank End Element to cap model

  1. Go to Solver → Analysis Setup →Working Fluid and set “Fluid Properties Option” to “30: All Water (L)”
    • This tells the model to use water as the fluid in the system

Step 4: Check Model and Run

  1. Select checkmark icon from the top toolbar to check the model for warnings/errors.
    • An error should populate stating that the internal chamber has not been initialized
  2. Select the initialization icon from the toolbar, and pick Start. Accept values once flow solver has converged.
  3. Select run icon from toolbar. Run Flow Simulator.

Step 5: Post-process

  1. Results file (*.res) should automatically be loaded into GUI. If not, it can be selected via File → Load Result File
  2. By default, both chamber and elemental results are displayed in the graphical workspace.
  3. Customization of the displayed results is accessible within Settings → Display Options
    • Display the flow in GPM and the static pressure.

Figure 1.14: GPM and Static Pressure near Junction 1