Could we set Check Valve with Two steps close operation? There should be such Check Valve with two steps close operation that we can set Damper of Check Valve.
If we cannot set Check Valve with two steps close operation, is it possible to add a TCV (CV+TCV) to simulate two steps Check Valve?
thanks a lot
Hello Jinlong,
For check valve element in Hammer you can only specify open and closure time, assuming it just slams open or close and not in stages. For slow closure of the check valve, you need to specify the delayed closure time in check valve element properties. When you model check valve along with pump, then there is only one option of instant closure.
However if you want to model that valve exclusively, then you use TCV element and specify the transient operating rule / pattern for that valve and observe the transient behavior.
Valve Type field assumptions and use with a TCV
Regards,
Sushma Choure
Bentley Technical Suppport
To add to Sushma's answer - if you need to model a non-linear closure of a check valve using the TCV element, the pattern of closure is static/manual. Meaning, it cannot be set to start closing upon detection of reverse flow. If you were to place a check valve next to the TCV, then both the TCV and the check valve would close, which isn't what you want.
Here is an article that goes into more detail on the actual closure aspect of modeling the TCV: Modeling Reference - Valve Closure
If the two "stages" of closure are a fast start followed by a slower finish, you could also consider checking the sensitivity by running the model with a check valve set to the slower rate, than another scenario with the check valve set to the faster rate.
In some cases, a faster closure of the check valve could produce more conservative results - if the check valve takes too long to close, reverse velocity can build up, compared to a faster closure where that reverse velocity may not have a chance to build up yet. See the note and illustration about this in the following article: Modeling Reference - Check valves
I have added this information to the check valve modeling reference article above, in the section "Multi-stage Check Valve Closure"
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.