gsphelp  Operating Envelope Scheduler

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gsphelp  Operating Envelope Scheduler

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CC_OperEnvSched

 

The Operating Envelope Scheduler can be used to create sweeps for sweeps of Flight/Ambient Conditions for a specific power setting sweep. This component adds Flight/Ambient Conditions in the models Ambient conditions transient table and a series of data points in the selected control's input transient table. Breaks are added in the Ambient Conditions transient table to define the last row of a sweep of a single parameter.

 

On the Flight/Ambient Conditions tab sheet the user defines the altitude, dTs (if ISA+ is chosen on the models off-design tab sheet of the Flight/Ambient Conditions form) and the speed of the aircraft/engine using the Start, End and Inc(rement) numeric fields. Upon changing the start-, end- or increment values the sequences are changed and directly displayed in a list below the numeric input fields. The numerical grids can be edited using the following keys:

Insert key        -        Insertion of a new row

Delete key        -        Deletion of the active line

Arrow keys        -        Navigate through the grid (note that if the active row is the last row, the "down arrow key" will add a new row to the grid)

Limits can be entered for airspeed, Vc, or dynamic head (defined as the difference between total and static pressure; Pt - Ps), and a minimum altitude. Note that compressible flow equations are used to calculate q and V. The limits cutoff the regions specified by the numerical grids. Note that points at the limits can be generated with option Outputs on limit.

 

On the Power/Control Settings tab sheet the user defines the control component and sets the control setting values for a sweep. Note that only control components that have transient input capability can be selected as this is used by the Operating envelope scheduler. This means that currently (with version 11.0.2.5) only the controls from the 'Controls' and 'Power' libraries can be selected. Normally typical power setting controls would be used such as

Manual fuel control and derived components

Thrust control

Nozzle control

Rotor speed control

Generic Power control and custom derivatives

Simple AB fuel control and derivatives

but also other controls can be used such as bleed controls to calculated bleed flow effects across the operating envelope.

 

On the Options tab sheet the user can select:

Auto-config model transient options

Specify the number of intervals between data points to decrease calculation stepsize and increase iteration stability.

Auto-deactivate non-looping transient inputs

Automatically deactivate all component transient inputs, to avoid interference with operating envelope schedule during steady-state series calculation.

Add Auto-breaks in table to separate data series

Add breaks in the Flight/Ambient conditions transient table to seperate data series so that the results can be plotted as individual sets.

Nr. of extra iteration intervals

Specify the number of intervals between data points to decrease calculation stepsize and increase iteration stability.

Start point nr.

Set to 1 to enable extra intervals for 1st point; leaving point 0 as unused start point in table; Note: only use either 0 or 1!

 

The buttons Generate Envelope and Graph generate and plot the flight envelope respectively.