Product(s):
HAMMER
Version(s):
CONNECT Edition, V8i
Area:
Modeling
Original Author:
Jesse Dringoli, Bentley Technical Support Group
Overview
This TechNote explains how the surge valve element works and its typical application…
Applies To
Product(s):
HAMMER
Version(s):
V8i, CONNECT Edition
Area:
Modeling
Original Author:
Jesse Dringoli, Bentley Technical Support Group
Overview
This TechNote explains how the Air Valve…
This is a list of articles containing general FAQs for Bentley WaterGEMS and WaterCAD products.
To search within this page, press [Ctrl]+F.
Calculations
Estimating pump specific speed
Transient Force Calculations
Input & Modeling
What…
The model illustrates the use of the air valve element. Several scenarios depict various configurations. This file is for demonstration purposes only.
Note: This model can be opened in HAMMER version 08.11.00.30 and above.
This example model illustrates different ways to model valve closure with a TCV. Advanced TCV closure modeling is not included.
Note: This model can be opened in HAMMER version 08.11.00.30 and above.
Product(s):
HAMMER
Version(s):
CONNECT Edition, V8i
Area:
Modeling
Overview
This TechNote explains how the Hydropneumatic Tank element works and its typical application in HAMMER.
For information on modeling h ydropneumatic…
Hi
I am currently modelling a number of pelton hydro station layouts. One option may (to be confirmed) include a tailrace tunnel with a free surface. Because the tail race tunnel is so long, surges upon start-up are a concern as could flood the pelton…
How does Hammer determine the pump speed during a power failure event? It's unclear without the input of the a power curve or torque curve how that data is derived. Are these values interpreted some way from the specific speed?
Also, what is the source…
Hello,
The minor loss coefficient for a hydropneumatic tank is the same standard minor loss coefficient (K) that you can enter for pipes (to represent bends, valves, etc). The head loss through the tank inlet orifice equals K*V 2 /2g , (the standard…
Velibor,
You need to enter the pump inertia. This is needed for a shutdown event, so HAMMER can correctly compute how the pump spins down. It is not needed with a constant speed pump because the pump isn't changing speed.
Regards,
…
Samir,
It looks like you're referring to Bentley HAMMER.
I believe you should be able to get the discharge coefficient from the valve manufacturer. If it's not available, you may be able to approximate it by back calculating the Cv from the orifice…
Hello subscribers,
We will be offering a Live training course on Transient Analysis and Design with Bentley HAMMER on November 26-29, 2012. This 16 hour course is being taught in 4 hour increments over the 4 days, from 11:00 a.m. to 3:00 p.m. EDT each…
Hello Sachin,
I assume that you're referring to Bentley HAMMER V8 XM or V8i.
1) There are many factors that contribute to the transient results that you see in HAMMER. Basically the configuration of all elements in your model can effect…
Hello,
The pumps are going to operate based on the system conditions (where the pump curve intersects the system head curve.) So, you'll need to "model what you've got" to get the right pump operating point. Meaning, if there aren't FCVs in reality…
I assume you're using Bentley HAMMER.
When you use a TCV or FCV, a discharge coefficient is calculated based on the head loss through the valve in the initial conditions. This discharge coefficient can be seen in the results section of the valve…
Hi
I am modelling a scheme which has a gravity lower than the standard 9.81 due to elevation.
Is there somewhere in Hammer to set this, as surely the available energy will change?
Hello Ahmed,
I would suggest trying both situations (one valve or two), then compare the results by closely examining graphs and profiles in the Transient Results Viewer (animating a profile path is a great start). This should show you if this arrangement…
Does anyone have a good resource for learning and understanding real world transient problems and models? I'm fairly new to transient analyses but I have been through the Bentley training course. I have a couple transient models that I am currently working…
Hello Ryan,
When the valve closes, the flow is basically zero. However, the presence of a reservoir (which has a constant hydraulic grade during the transient simulation) may cause small flows in the pipe after the valve is closed. These small…
Hello Inbarasan,
I'm a bit unclear on some of what you said, but I'll try my best to address your questions:
"...which is the effective shape in orifice?"
The surge tank orifice is assumed to be circular, as you must enter a diameter. If the…
I'm trying to evaluate the need for surge protection at new well locations in a raw water transmission system. I have a network of 6 wells all pumping to the water treatment plant. I'm new to Water Hammer and surge analysis so I'm just looking for some…
When modelling a surge tank it is necessary to dictate the initial level. When the steady state conditions are calculated, this seems to not affect the surge tank initial level, even if it does not match the head at the point on the line where it is installed…
Hi I wish to clarify how the Turbine Curve should be sourced for inputting into Hammer in relation to which quadrant curve is being used.
I understand the Quadrant curve is defined by the selection of the specific speed. In my case, I am picking a…
Hi When calculating the turbine specific speed to use in Hammer, is it more accurate to use the values for P, H, Q & n at the turbine best efficient point or rated point? The specific speed for these two operating points will differ.
Kind regards