The Spray Discharge junction must have at least one connecting pipe, and it allows up to four. This junction offers a flexible way of modeling a flow exiting the system through a nozzle or spray device. The flow occurs across a user specified hydraulic loss such as a discharge coefficient. This can be varied with time to open or close the Spray Discharge junction.

The Spray Discharge Properties window follows the second of the two basic Properties window formats. A table displays the connecting pipe information. The pipe table grows in size to accommodate up to four connecting pipes.

The exit pressure to which the Spray Discharge junction discharges must be entered.

Two geometries can be modeled. The first is a normal, one hole spray, where the discharge flow area of the hole is entered. The second is a sparger which, in principle, works in the same way as a spray. For the sparger, the flow area of a single hole and the number of holes are entered. This assumes that the holes are hydraulically close in proximity and are the same area.

For each connecting pipe, the pipe table on the Pipe Losses tab lists the reference flow direction and up to two loss factors. The first loss factor is for physical flow out of the pipe and into the junction, the second is for physical flow into the pipe and out of the junction. The loss factors can be specified independently or left as zero. To edit within the pipe table, click in the appropriate column and row.

The distance of each connecting pipe (if any difference exists) from the elevation can be entered in the pipe table.

Loss Model

The discharge coefficient for the junction is entered under the Loss Model tab in the box near the bottom of the window. The physical area of the exit flow can also be entered under the discharge coefficient input box. These two parameters are used to calculate the discharge flow rate, which depends on the difference between the internal pressure in the system and the specified exit pressure.

The K Fire Sprinkler model uses the K value as defined by the fire sprinkler industry. Whereas the standard K loss value is dimensionless, the K Fire Sprinkler has units associated with it. You can adjust these units according to your data.

Transient Data

On the transient data tab the discharge flow area or K data can be varied with time to simulate the opening or closing of the junction. For more information on transient data, including event transients, see Junction Transient Data.

Graphing Spray Discharge Data

You can track the discharge flowrate and total mass or volume discharged at the spray discharge junction by selecting to save the transient output for these junctions in the Output Junctions panel of the Pipe Sectioning and Output group. These parameters can be graphed or reviewed in the Output window.