| Applies To | |||
| Product(s): | HAMMER | ||
| Version(s): | 08.11.XX.XX and higher | ||
| Area: | Output and Reporting |
The following user notification appears when trying to apply an Operating Rule pattern to open and/or close a valve element during a transient simulation in HAMMER:
"The valve's Initial Closure percent does not match the initial closure percent in the valve's referenced Operating Rule. The Operating Rule will be used as specified, but should be modified in order to get the expected results."
This notification means that the Starting Relative Closure in your transient operating rule is not in agreement with the initial conditions of the valve. Check the "Relative Closure (Calculated)" field in the "Results" section of the properties of the TCV, to see what the initial relative closure is (which is calculated based on the initial discharge coefficient, fully open discharge coefficient and valve characteristic curve). You'll need to adjust the initial discharge coefficient so that the initial relative closure matches your pattern, or adjust the starting multiplier in your transient operating rule so that it matches the computed initial relative closure.
For example if the valve's operating rule pattern starts with 100% relative closure, then the valve's initial status is expected to be Closed with 100% relative closure.
If you're using a GPV, you will need to convert it to an equivalent TCV, using the method described further in this article. As of the CONNECT Edition, an FCV, PRV, PSV and PBV all support reporting the relative closure (in the results section of the properties) and an Operating Rule to start at that position and change it over the course of the transient simulation
When using a PRV with a "fixed" operating rule and the Modulating option disabled, this notification can occur. The problem in this case is with the calculated Relative Closure, which you can see in the "results" section of the PRV properties. This is calculated based on the calculated discharge coefficient during the initial conditions, the fully open headloss characteristics (by way of the Minor Loss Coefficient field) and the valve type (such as "globe" or "butterfly").
Based on this input, the program can determine the initial relative closure in percent. This is mainly important when you're using the modulating PRV option (which adjusts the % closure from the initial position, based on changes in the hydraulics and the open/closure rate coefficients that you specify) or if you choose to control the valve manually using an operating rule (in which case the start of the operating rule should match the initial relative closure as the user notification mentions).
However, you can run into this issue even when not using the modulating option and when the operating rules are set to fixed. This can happen if a minor loss coefficient is specified, which allows the program to calculate the initial relative closure as mentioned above. With this specific combination, the user notification (initial closure not matching the operating rule) can be ignored. Alternatively, you may want to consider the modulating option, if you would like the PRVs to dynamically modulate (open or close) during the transient simulation, as opposed to assuming they're in a fixed position (fixed discharge coefficient)
Note: this has been logged as defect # 170556 so that future HAMMER versions (after 08.11.05.61) will not generate such a user notification in this situation.