AFT Impulse Details

Details

AFT Impulse is a practical tool to address the complex subject of waterhammer and surge transient events in liquid piping systems.

  • Understand the transient response of your system, knowing how valves, pumps and other components will dynamically interact with each other.
  • Evaluate the effect of pressure surges due to vapor cavity collapse by modeling vapor cavitation and liquid column separation.
  • Produce safer, more economical pipe systems.

How does it work?

AFT Impulse incorporates a steady-state solver providing seamless transfer of initial conditions to the transient analysis.
Steady- state solutions are determined using a modified Newton- Raphson matrix iteration.

The traditional Method of Characteristics is used to solve the transient mass and momentum equations of pipe flow.

With AFT Impulse you can….

  • Model a wide range of system components and surge devices for both design and operational cases.
  • Initiate transients based on time or events in the system.
  • Reduce surge magnitudes by slowing system changes such as valve closures or pump speed.
  • Minimize the adverse effects of surge by changing piping or equipment to reduce velocities.
  • Calculate transient unbalanced forces and define forces sets as location pairs or single points.
  • Specify alerts that automatically highlight output values that are out of range for flow, pressure or velocity.
  • Compile catalogs of your frequently used piping components and quickly select them from a drop down list.
  • Customize and configure your workspace.

Modeling Features

Pumps

  • Implements the Sutter method for inertial modeling of both the motor and entrained fluid
  • Four-quadrant modeling allows for reversed-flow and reversed-speed operations
  • Set startup and trip/shut down for a specific time or based on a system event
  • Model centrifugal and positive displacement pumps
  • Model pumps with variable speed controllers

Valves

  • Model flow control and pressure control valves
  • Model relief valves that are in-line with the pipeline or that relieve to atmosphere
  • Change control valve set points over time

Surge Suppression

  • Identify and test surge suppression devices and where they are best placed in your system
  • Model gas accumulators and surge tanks to minimize pressure spikes
  • Model vacuum breaker valves as either 2-stage or 3-stage and include air release capability
  • Model relief valves to protect sensitive equipment

Scenario Manager

  • Evaluate “What-if” cases by comparing several scenarios
  • Make data changes in one scenario which can be passed down to dependent scenarios
  • Easily develop and switch between different operating conditions or configurations (for example: three pumps running vs. two pumps running with one pump tripped)
  • Evaluate new or expanding system configurations

Reporting Features

Output Window

  • Display reporting sections all at once or individually:
    • General:
      • information about the model and analysis
      • tabs with specifically formatted output for valves, pumps and other specialized system components
      • a summary of when events occurred
    • Pipes section:
      • initial steady-state data
      • transient maximum/minimum by pipe
      • transient output data for each pipe segment at each time step
    • Junctions section:
      • summary output for all junctions
      • tabs for each type of junction present in the model
      • transient junction data for each time step
  • Select output format, units and displayed items through Output Control
  • Make changes to the format without re-running the analysis
  • Export results to a file or copy/paste into Excel for additional reporting options

Graph Results

  • Graph a wide variety of output data such as plot flows, pressures, velocities, and more vs. time
  • Supports both instantaneous flow and integrated flow plots
  • Customize graph formats
  • Animated graphs dynamically display results for one or multiple flow paths

Viewer

Share your models with anyone who may not need a full version of AFT Impulse. The Viewer is a free application that lets you:

  • Open a model and view any of the windows (Workspace, Model Data, Output, Visual Report, Graph Results)
  • Run the model and graph output data
  • Print and export data
  • You cannot edit an existing model or create new models with the Viewer.