• Hammer - Setting gravity

    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?
  • Hammer: Pelton free-surface tailrace surge

    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…
  • Water Hammer Pump Data

    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…
  • Re: Modeling a 1.5 second valve closure at Airplane Fueling Nozzle?

    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…
  • Hammer Analysis in Raw Water Transmission System

    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…
  • Hammer: Surge Tank Initial Level

    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…
  • Hammer: Turbine Curve in Relation to Quadrant Curve

    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…
  • Hammer - Turbine Specific Speed Operating Point

    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
  • Hammer - Modelling vertical pipes

    I am modelling a hydro scheme which features a vertical shaft directly at the intake. So lets says the intake is J1 at elevation 100m and drops to J2 at 50m by a 50 m length of pipe before completing a 90 degree bend to horizontal. Whe using the profile…
  • Moment of Inertia Turbine Input - Hammer

    Hi I am trouble shooting a Hammer model of a hydro scheme which is producing unexpected results. I have some confusion around which inertia Hammer uses. For hydro generation applications inertia is usually given as WR2 or GD2, with GD2 being four times…
  • Control valve response to transient event

    Is there a way to model the response of a control valve to a transient event beyond manually inputting the transient operational pattern? An example would be what happens to a PSV when the transient pressure drops below the pressure set point.
  • Re: Hammer: Pelton free-surface tailrace surge

    Hi, thanks for your reply. You are correct; I am looking at the pipe carrying the water away. I have attached a basic sketch. I am modelling the pelton as a TCV followed by a D2A so I can have multi-stage valve control. Typically I would only be interested…
  • preneting WATER HAMMER in a gravity pipeline with PRV1

    HI i am designing a 24.5 Km gravity water pipeline consists of: 5500m Steep pipe 350mm diameter 9000m GRP pipe 350mm diameter 10000m GRP pipe 250mm diameter i used 3 PRV to reduce high static pressure. i know in HAMMER,A PRV will not react dynamically…
  • Hammer - Arranging Pipe FlexTable Order

    Hi This may be a silly question, however I have been modelling a hydro station and in setting up the model, when viewing the pipe flextable, the pipes are not listed in sequential order, but in the order which they were added. I understand you…
  • Hammer: Turbine Instant Load Rejection Modelling

    There is one point regarding turbine modelling which is causing me confusion. The instant load rejection scenario requires the turbine to start at 100% gate, is it possible to start at a lower gate opening, as typically the BEP is not at 100% gate. Or…
  • Initial conditions,KNOWN water level in the tank in every time step

    Regards to all. The existing water supply network belongs to III elevation zones of much larger water supply system and ends with the tank of III elevation zone. It is necessary to design new water supply network of IV elevation zone. In the…
  • Hammer Negative Pressure - Instability at Steady State

    Hello, I am using Hammer V8i. I have a simple layout for a pump station transient model. A pump draws from a wet well, and discharges over a syphon into an effluent conduit. The discharge syphon creates a negative pressure at steady state. My transient…
  • Hammer Pump Transient Properties

    Is there anyway to make a responsible assumption for the pump transient properties if accurate data is not available? I have a distribution system model that I've been asked to do some transient analysis for. The model has detailed pump curves but I don…
  • Cla-Val Control Valves in Water Hammer

    Has anyone simulated a Cla-Val surge anticipator (Model 52-03) or surge relief valve (Model 50-01) in Water Hammer? The surge anticipator valve seems straight forward, but I'm not sure what kind of variables to use for time to open, time stays open, or…
  • Pump start simulation at Hammer v8XM

    I want to simulate a pump start at Bentley Hammer v8XM. Can someone explain to me the whole process. Pump doesnt come with a valve, down at the pipeline I have a GPV that works as a no return valve with varius time steps. I found a post here but…
  • Distribution Sytem Wide Hammer and Transient Analysis of RPZ

    I am attempting to set up a model to demonstrate how a RPZ (Reduced Pressure Principle Backflow Preventer) will respond to Hammer. For those unfamiliar with the operation of an RPZ, I have attached a document which outlines this very well. …
  • Hammer Protection Device (Help)

    Dear; I am new in using water hammer software. and i have a project which consist of 900 mm transmission line with pump station. I modeled the project for pump shut down due to power failure and i viewed the results for upsurge and downsurge reults…
  • Old HAMMER Files

    I have some old HAMMER files that were created in November of 2004. I am able to open the .hif files, but the models cannot be run. The first thing that there was an error for was for no pump curve data. Is there a way to access additional data in the…
  • Water Distribution Modeling Software Survey

    Hello, If you have a few minutes please fill out this short survey to help the Bentley Institute Geospatial team create better training that is more suited to the workflow of our users. http://www.surveygizmo.com/s3/568508/Water-Distribution-Modeling…
  • Re: Hammer: Surge Tank Initial Level

    Hi Jesse, thanks for your reply. I do have my tank set up as a junction with no check valve, and as you mention this tank level should follow the HGL. My version is 08.11.03.17 which isn't too old I thought? It seems the steady state isn't accounting…