Hi,
I am modelling a simple system to compare the results to some codes that I have. But, despite having all the configurations similar to codes, I cannot get similar pressure fluctuation. Could you please have a look and let me know the reason?
Thanks in advance.
Regards,
Example 1.xlsx8233.Example 1.zip
Here is some information from our Wiki to supplement Mal's response about cavitation:
What standard method does HAMMER use to simulate vapor pockets? (column separation / Cavitation)
Assumptions and limitations of tracking air or vapor pockets in HAMMER
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Answer Verified By: Hiwa
Dear Mal,
Very good point. I appreciate it. Yes, you are right please see the attachment. I am not using a cavitation model.
But for the other one, I didn't have the negative pressure (as you see below). Do you have any comment on improving accuracy?
Hiwa
Hiwa said:But for the other one, I didn't have the negative pressure (as you see below). Do you have any comment on improving accuracy?
It could be due to a difference in how the valve characteristics are modeled, or with the discharge-to-atmosphere (D2A) pressure vs. flow characteristics. What assumptions are you making in your program for these elements? This article explains the Ball valve characteristics and this article explains how the D2A works. If you change the valve type, you will see a large difference in the pressure time history. For example if you try the Globe valve type instead of Ball, the results will be quite close.
Thanks Jesse,
Yes, it worked and now the results are quite similar! Could you please introduce me a reference on the difference between different valve actuation in Hammer?