Design Flow Network Models in APS with a deterministic flow direction

For the Line Blockage application to function reliably, a flow direction needs to be determined in any given flow network model. Consider the example below where an AVEVA Process Simulation (APS) model can result in an open loop causing Line Blockage to not be able to determine direction of flow.

Example 1:

If an uncontrolled terminal is treated as both a source and a destination, and is upstream of two, parallel valves, an open loop results when the downstream valve is blocked.

To avoid the above result, place one or more check valves in the flow network to control the flow direction. See the following solutions:

• In the first solution, a check valve is inserted next to the terminal, and the terminal is limited to only inject or deliver.

  

• In the second solution, check valves controlling flow direction are inserted upstream of each of the parallel valves.

  

  Important: To help with the accuracy and the performance of the flow network algorithms, we recommend that check valves be used wherever the flow is known to be physically constrained.