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Applied Flow Technology

Applying a Default Unit System

AFT software supports ISO and English units and provides a variety of ways to select the units to be used. For example, in the Output window you can change units 'on the fly' for a specific parameter by double clicking an output column header and selecting the desired unit from the Change Units window. To globally change the unit system, go to the Options menu and select Parameter and Units Preferences. Select the Unit Preferences tab, choose the Default Unit System then click the Apply Default Units button. This will both apply the default units for the selected unit system and...
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Applied Flow Technology

Setting Preferred Units

To choose only English or SI units, go to the Options menu, select Parameter & Unit Preferences, then the Unit Preferences tab. Choose the Default Unit System then click the Apply Default Units button. This will set the units to be used both on input and output windows.
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Applied Flow Technology

Modeling Valve Opening in Fathom XTS

To model a valve opening transient from the closed position, apply the Special Condition / Closed on the specifications window Optional tab. Transient Data then starts with Cv = 0, increasing to the full open Cv value, or, if modeling the valve loss as a K value, transient data starts with K = -1 (K = infinity), decreasing to a K value for the open position (all K values other than the full closed K value are positive).
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Applied Flow Technology

Reviewing Output in the Workspace Window

You can see output in the Workspace window by pressing the CTL key while right-clicking a pipe or junction (left-clicking for a left handed mouse). Output displayed is that currently selected within Output Control so, if you don’t see the information you’re looking for, simply open Output Control from the Analysis menu and add the desired parameter to the ‘Show Output’ list.
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Applied Flow Technology

Design Alerts

Design Alerts provide easy identification of output parameters that exceed specified limits and are available in all AFT pipe flow modeling software. Found on the Design Alerts tab of the Pipe Specifications window, an alert is defined by; Selecting the parameter upon which the alert is based from the available list (pressure, flow, velocity, etc.), Checking ‘Minimum’ or ‘Maximum’ (i.e. alert if the parameter value falls below the specified minimum of above the specified maximum), Specifying the value and units and, Clicking the ‘Add’ button to add it to the alert list. Any number of alerts may be defined for a...
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Applied Flow Technology

Modeling Component Resistance Curves

A variety of resistance modeling methods are available within AFT software , including constant or variable K values for a wide variety of components, K or Cv for valves. Also, for most components, you may directly model a resistance curve. This is especially handy when you pressure drop (or head loss) vs. flow data from the component manufacturer or test data. Whether you're modeling a valve, spray discharge, orifice or general component junction, you'll find this option on the Loss Model tab of the junction specification window listed as "Resistance Curve". Clicking the button will highlight an 'Enter Curve Data' button,...
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Applied Flow Technology

Backup Files

Every once in a while users will ask 'what are those .001 files created in my model folders?'. Answer - These are backup files of your model. When the model is saved the previous version is saved with the same name and the extension .001. This file can be opened or renamed if desired. By default one level of backup file is created and saved, but you can specify up to 10 levels of backup files in Options / General Preferences / User Environment tab. While there, you'll also see the option to have backups created automatically on a time frequency...
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