This feature displays the position of a check valve at each time step of the simulation. The check valve ratio graph is accessible by opening up a node graph and clicking on the check valve button.
1. Display the Check Valve Ratio from within a Node Graph
A check valve position of 1.0 means the check valve is fully open, a position of 0.0 means the check valve is fully closed.
2. Example Check Valve Ratio Graph for a Pump
This graph is available only in KYPipe and Surge: Surge determines check valve ratios at each point of a model-determined time step; KYPipe reports the check valve ratio for each steady-state case, or for each user-specified time step during an Extended Period Simulation.
During system design, users can run a simulation, adjust the system layout, add or modify surge protection devices and/or alter the characteristics of the check valve, and then rerun the simulation iteratively until acceptable pressures are reached. Within the graph, users can press the Display Previous Results button to temporarily see the results of the last simulation and determine if the most recent changes resulted in improved performance of the check valve.
3. Compare Graphs of System Performance before and after Implementing Transient Controls
Check valve ratios are available for the check valve element, as well as check valves added to devices such as pumps, active valves or loss elements. However, the check valve ratio is not available for the check valve internal node, which simply closes it’s pipe immediately and completely upon flow reversal, and thus does not have a position (besides open or closed) to display. Because of this, the check valve internal node is not permitted within Surge.
In Surge, this graph can be used to determine the presence of check valve chatter: see Dr. Srinivasa Lingireddy’s blog post on non-reopening check valves for further information on check valve chatter.
4. Example Graph of Check Valve Chatter at a Pump CV
