Hi,
I note in the help file for the Surge valves that the SRVs acceleration of the spring and plate is ignored. If I know the time for the valve to open for a given pressure differential, or the mass of the moving parts, is it possible to include an acceleration rate for the valve in the transient model?
Thank you for your assistance.
Regards,
Luke
Hello Luke,
Could you clarify what you mean by "include"?
You can use the User Data Extensions feature (tools menu, see Help for documentation) to add a custom field to store your externally-calculated acceleration rate for reference purposes. Aside from this, HAMMER will always use the documented equations and assumptions for hydraulic calculations during the transient simulation. An estimate of the spring constant and threshold pressure is typically sufficient for transient modeling purposes. From the specifications of your valve, you should be able to calculate these values. If uncertain, try a sensitivity analysis, varying the uncertain parameter.
If you haven't seen it already, check out the below Surge Valve reference technical article. In particular, it includes a link to a spreadsheet documenting the equation used to calculate SRV flow.
Modeling Reference - Surge Valves
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Answer Verified By: Sushma Choure
Thank you for your response.
My reference to "include" was to ask if Hammer can take into account the additional force (and time delay) for opening the valve (due to the valves inertia). My understanding from your comments above is that I could take this into consideration adjusting the spring constant (for addition force to accelerate the mass) and conduct a sensitivity analysis on this.
Thanks,