Gas Turb 11 Control System

Copyright © Joachim Kurzke

Introducing GasTurb 11

Control System Simulation


GasTurb 11 Main Window

Select the engine architecture from the Configuration List.

Alternatively you could select it from the Configuration Tree.


The Engine Configuration List

Select the Turbojet…

... use the Scope Performance

with the Calculation Mode Off-Design

and choose for the Maps Standard

The file opening menu will appear automatically,

read the file Demo_jet.cyc

After reading the data, the cycle design point will be

calculated in the background before the Off-Design Input

Window opens.


Off-Design Input Window

The control system protects the engine by limiting temperatures, pressures, spool speeds etc.

Click the Limiters tab.


Max Limits

You can set switch on several limiters simultaneously. The

limiter which restricts the engine most will fix the operating point.

Enter numbers here

Activate the selected limiters

Click the Max Limiter option


Solution for Three Active Limiters

Active Limiter

T3,max=650K

Nrel,max=101%

The Turb Exit Temperature T5 limiter is active, neither the Spool Speed NH limit nor the

Compressor Exit Temperature T3 limit is violated


Fuel Flow and Thrust as Pseudo Limiters

You may want to run the engine to a given thrust.

Enter the desired thrust

Activate the limiter here


The Cycle for 25kN Thrust



HPC Spool Speed ZXNwith Activated Limiters

If any limiter is active, then the input for ZXN given (1) or ZT4 given (2)

is automatically set to 1.

The HP Spool Speed ZXN is no longer seen on this page


If you want to consider a limiter which is not on the Limiters page,

then define a composed value.

While a limiter is active, HP Spool Speed ZXN is an iteration variable


Any Composed Value can be employed as Limiter.

Introduce as a P5Limiter the ratio of P5/P2, for example.

Close this window and go to the Limiters page


Click to see the composed value


The P5/P2 Limiter is Active


De-select the P5Limiter

Besides single valued limiters you can also employ

Control Schedules


Defining a Control Schedule

1 Select the parameter to be controlled

2 Select the parameter from which the controlled parameter

depends

3 Enter numbers

Plot the schedule

Click to activate the schedule

Keep in mind:At T2=300K T5 = 1110K.


T5 Controlled to a Schedule


Changing Ambient Temperature

Delta T from ISA = 11.85K yields at sea level static conditions

T2=300K


T5 Follows the Schedule

Remember:T2 = 300K yields as

scheduled T5 = 1110K.


T5 Controlled to a Schedule

Next we introduce a nozzle area schedule.


Nozzle Area Schedule

We will use this Delta Nozzle Area schedule for increasing the surge margin of the compressor at

low corrected speed.

Before continuing, select Turb Exit Temperature T5

from the parameter list and click the bulb to make this limiter

schedule inactive.


Run Two Operating Lines

To demonstrate the effect of the schedule, we run two operating lines:

- one with scheduled nozzle area- the other with nominal A8


After the 1st Operating Line is Completed

Choose 16 for the Number of Pointsbefore running the 1st operating line


Next Operating Line

Nozzle Area follows a schedule.

1 Click and de-activate the nozzle

area schedule

2 Add some descriptive text

3 Run one more operating line. When asked

Another operating line ? Click No


Effect of the Delta A8 Schedule on the Compressor Operating Line

Nozzle Area follows the schedule.

This slide ends the Control System

Simulation Tutorial

Increased surge margin because the nozzle

opens at low corrected spool speeds

Documents

Gas Turb 11 Control System