1D Pumps: Difference between revisions

This post provides a modelling example for a 1D pump using a fixed flow rate and pump curve. For this example we will set up a pump in two common situations (2D-2D & 1D-2D).

A pump needs to first be digitised in a 1d_nwke layer. The direction of the polyline must go from inlet to outlet as a pump is unidirectional (see Section 5.9.2.1 Pumps). The attributes required for a pump in your 1d_nwk layer can be found withinin the 2018<u>[https://docs.tuflow.com/classic-hpc/manual/latest/ TUFLOW manualManual]</u>.<br>

BecauseAs pumps are zero length channels, they do not create automatic nodes at the upstream and downstream end. If you ran the model with just a pump polyline and SX connection, you will get <u>[[TUFLOW_Message_1353| <font color="red"><tt>ERROR 1353 - No NA data for Node]]</tt></font><ttu>.</tt>]] To remove this error, the most efficient schematisation is to digitise a 1d_nwk 'NODE' at the upstream and downstream end of the pump (no need for a separate 2d_bc SX layer). TheUnlike 'NODE'NODEs requiresconnected ato nominalpipes storageand amount in the “Len_or_NA” attributechannels, inNODEs addition infill 'SX' into the "Conn_1D_2D" attributeconnected to connectzero thelength 1dpumps pump torequire the 2Dfollowing domain. SX connections are required at connections to 2D domains to transfer water from the 1D node to the 2D. Without the SX connection, water will build up within the node and cause an instability. See the example below.attributes:<br>

[[File:Pump_schematic.PNG|border|600px]] <br>

Within the *.ecf the following commands and files are at a minimum required to run a pump with no logicallylogical controlcontrols:<br>

If you do not specify a Depth-Discharge database then you will be faced with <font color="red"u><tt>ERROR[[TUFLOW Message 1118 –| CouldERROR not find a y-Q curve1118]]</tt></font><ttu>.</tt><br>

For guidance on setting up the operating controls for pumps, seerefer sectionto 5the <u>[https://docs.9tuflow. in the com/classic-hpc/manual/latest/ TUFLOW Manual]</u>. <br>

The depth discharge database is set up in the same way as a pit inlet database, see(refer 5.12.4 into the <u>[https://docs.tuflow.com/classic-hpc/manual/latest/ TUFLOW manualManual]</u>). Each pump ‘Inlet_type’ must reference a name within the depth discharge database, otherwise <u>[[TUFLOW_Message_1118 | <font color="red"><tt>ERROR 1118]]</u> - Could not find pit inlet type ",a," in the pit inlet database</tt></font><tt></tt>]]. The ‘Area (m2)’ column is the area of the pump offtake and ‘Width (m)’ column is the width of the pump offtake. Without information in the Area(m2) or Width(m) columns in the depth discharge database <fontu>[[TUFLOW color="red"><tt>ErrorMessage 1092|ERROR 1092]]</tt></font><tt></ttu> and <font color="red"u><tt>Error[[TUFLOW Message 1093|ERROR 1093]]</tt></font><tt></ttu> will appear. <br>

The use of pump curves within TUFLOW requires a 2015 or later build. The setup of the Depth Discharge database for a pump curve is similar to reading in inflow hydrographs, hyetographs etc, that is; a source .csv, and the two corresponding headings within the 3rd and 4th column. <br>

Once you have your manufacturer curve for your given pump it is now necessary to create the curve .csv for TUFLOW to read in. The manufacturer specifications will need to be translated into a total head vs pump rate chart. Although reading in the depth discharge database is the same process as other boundary conditions within TUFLOW, the curve itself is fundamentally different as you no longer need to start the csv file with 0,0. If the curve did start at 0,0 this would not make sense because at a total head difference of 0m the pump should effectively be operating at peak performance so the flow rate would be greater than 0 m3. This is why builds prior to 2015 cannot be used with pump curves as it still requires csv dbase entries to start at 0,0. The image below shows a csv file for the pump performance curve given in the previous section. <br>