Dynamic solutions for a fluid world™

Goal Seek & Control (GSC)

An AFT Fathom Add-on Module

AFT Fathom GSC Module frees you from time-consuming manual iteration so you
can quickly find the input values necessary to meet the hydraulic behavior you
want to simulate. Simply enter your variables and goals, and GSC
will automate the iterative process for you.

With the AFT Fathom GSC module you can:

One of the powerful benefits of system modeling is the ability to evaluate the effects of changing system parameters.

  • Save time by avoiding manual iterative analyses
  • Define multiple variables and goals at multiple locations throughout the system
  • Answer questions such as:
    • What pump speed will achieve a specified total flow to multiple, remote tanks?
    • What positioning of multiple valves will yield a desired differential supply pressure between pieces of equipment in your system?
  • Increase your productivity

Modeling parameters that may be used as variables or goals include:

  • Pumps - speed, flow, head rise, impeller diameter
  • Valves - open percent, Cv/K, deltaP, flow
  • Reservoirs - liquid level, temperature
  • Control valves - setpoint, open percent
  • Orifice - diameter, area
  • Heat exchangers - heat rate, temperatures, area, U value
  • Spray discharge - area, K value, exit pressure

Goal Seek & Control FAQ's

What is the difference between goal seeking and control?

AFT Fathom GSC, Goal Seek & Control, Module extends Fathom's capabilities in two ways.
  1. Goal seeking, automatically finding the value of one or more inputs that will produce a specify value for one or more outputs.
  2. Extends AFT Fathom's control modeling capabilities to remote sensing.
AFT Fathom can model flow and pressure control valves and controlled, variable speed pumps. With basic Fathom, the variable controlled is the one at the control component. That is, a pressure reducing valve controls the outlet pressure at the valve.

With GSC, control can be based on a variable located anywhere in the system. Instead of controlling the pressure at the valve outlet, it could be a pressure downstream at some other location.

Additionally, control can be based on the difference between two variables, such as a differential pressure between two points, and on group sums, maximums or minimums, simulating some of the more sophisticated control logic that is sometimes implemented in real systems through computer based control systems.

Is there a limit on the number of variables and goals the AFT Fathom GSC Module can handle?

While there is no limit, the time required to find a solution will increase with the number of variables and goals that must be solved.

The AFT Fathom GSC Module employs a robust and efficient numerical optimization engine to be able to handle models with large numbers of variables and goals.



Do I have to have one Fathom GSC module license for each AFT Fathom license?

No, there does not need to be a one-to-one relationship in the number of Fathom GSC and AFT Fathom modules. This provides users the flexibility to choose the level of capability they need.

For example, you may have several AFT Fathom licenses deployed on your network but only need to use Fathom GSC half the time and, therefore, have a correspondingly lower number of GSC licenses. If you open a model previously saved using Fathom GSC, AFT Fathom will first try to activate the GSC module. If all of the GSC licenses are being used, a message will be displayed telling you a GSC license is not available and provide you a choice of continuing to open the model or canceling the load.

This same message will remind you that if you do open and work with the model, GSC specifications contained in the model may be lost.