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CYCLE DESIGN PARAMETRIC STUDY

GasTurb 12 – Tutorial 2

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GasTurb 12 Main Window

For this tutorial we will consider a 2 Spool Turbofan.

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We Need Some Data

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Input Data Page

First we run a single cycle

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Single Cycle Output

This is a cycle for a business jet engine. Cruise flight condition is 11000m @ Mach

0.8. The overall pressure ratio is rather low (P3/P2=17.33), burner exit temperature is

1450K and the bypass ratio is 6.

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Turbofan Station Designation

These are the locations of the thermodynamic stations and the secondary air system paths

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Parametric Study

Now we go for a Parametric study.

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Parameter Selection

Click here to run all cases

This is the HP Compressor Pressure Ratio of the Single Cycle calculated before this

parametric study.

Choose a property from the list, double click or drag it to the parameter page on the right. You can also click the arrow for

moving a parameter from left to right.

We employ HP Compressor Pressure Ratio as the only parameter for now.

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Graphical OutputPicture Definition

The result of a parametric study is presented graphically. Sp. Fuel Consumption and Net Thrust

are the default plot parameters. To employ Overall Pressure Ratio P3/P2

as x-axis, drag it to the box below the schematic picture. Then click Draw y=f(x)

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Single ParameterPlot With a Single Y-Axis

We go back to the previous window and select a new view

(New Picture) of the data created in the Parametric Study

This black square marks the Cycle calculated before

beginning the Parametric study

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Single ParameterA Plot With Several Y-Axes

We will employ several y-axes

Drag four parameters to the respective y-axis boxes. Then

click Draw y=f(x)

Select the number of y-axes first!

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Plot With Four Y-AxesOn each y-axis there is

a different symbol.This line belongs to the

LPT Pressure Ratio axis – the symbols on

the line and on the axis are the same.

Close this window to go for a new Parametric

study.

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Parameter SelectionAdding a Second Parameter

We employ Burner Exit Temperature as the second parameter

Click this tab for specifying the

second parameter

This is the Burner Exit Temperature of the cycle calculated before this Parametric study.

Click here to run all cases

Use these numbers

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The Default PlotNo Contour Lines

This little black square marks the cycle calculated

before beginning the Parametric study

Next have a look at all the data from a specific parameter combination.

Click Detailed Output

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Getting the Detailed Output for any Parameter Combination

SELECT

Double click (in GasTurb) to select T4=1425 and

HPC Pressure Ratio = 9

Now we will add more information to the

picture. Click New Picture

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Contour Parameter Selection

An option: Click to sort the

property names alphabetically

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Plot with Contours

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Editing ContoursEdit the numbers:Lowest Contour Value = 0.435Step Size = 0.005Click to apply the

new settings

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The Customized Plot

Let us add now a design limit for T45 of 1200 K to the carpet.

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Showing Design LimitsExample: Add a Boundary for T45>1200K

Upper or lower limit

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Showing Design Limits

Next we go for another

New Picture

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Specific Fuel Consumption (SFC) as a Function of HPT Pressure Ratio

Sometimes the lines are overlapping and the plot is

difficult to read

Changing the Layout resolves this problem

The disadvantage of this plot is that there is no information about HPT Pressure Ratio anymore.

To correct for that we add contour lines for HPT Pressure Ratio.We go for

another New Picture

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Specific Fuel Consumption (SFC) as a Function of Ideal Jet Velocity Ratio V18/V8

For each HP Compressor Pressure Ratio the best SFC is achieved if the Ideal Jet Velocity Ratio V18/V8 is approximately 0.8. This relation between the bypass nozzle velocity V18 and the core nozzle velocity V8 can be achieved by choosing the right Outer Fan Pressure Ratio.

In the next parametric study we will iterate Outer Fan Pressure Ratio in such a way that the Ideal Jet Velocity Ratio V18/V8 is equal to 0.8. Thus all the cycles are optimized for Specific Fuel Consumption SFC .

Closing this window brings us back to the cycle design input window

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Go for Iterations

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Define the Iteration

How to define an iteration is shown in the Single Cycle Tutorial

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Re-Run the Parametric Study

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No Change in this Window

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Outer Fan Pressure Ratio is Optimized

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GasTurb Copy to Clipboard,Pasted into Power Point and Re-Sized

26.07.2012 GasTurb 12

2,8 3 3,2 3,4 3,6 3,8Net Thrust [kN]

18,25

18,5

18,75

19

19,25

19,5

19,75

20

20,25

20,5

Sp.

Fue

l Con

sum

ptio

n [g

/(kN

*s)]

HP Compressor Pressure Ratio = 5 ... 9 Burner Exit Temperature = 1400 ... 1600 [K]

1400

1425

14501475

15001525

1550

1575

1600

5

6

7

8

9

1%

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De-Activating the Iteration

Click to de-activate the iteration

Now run the Parametric study

again

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Outer Fan Pressure Ratio = 1.8Iteration is De-Activated

Adjust the scales to make the picture comparable to the picture

with the optimized Outer Fan Pressure Ratio.

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Outer Fan Pressure Ratio = 1.8

Repeat clicking this button until no parameter

values are shown

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Outer Fan Pressure Ratio = 1.8

Select a color

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The Overlay on the Clipboard

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26.07.2012 GasTurb 12

2,8 3 3,2 3,4 3,6 3,8Net Thrust [kN]

18,25

18,5

18,75

19

19,25

19,5

19,75

20

20,25

20,5

Sp.

Fue

l Con

sum

ptio

n [g

/(kN

*s)]

HP Compressor Pressure Ratio = 5 ... 9 Burner Exit Temperature = 1400 ... 1600 [K]

1400

1425

14501475

15001525

1550

1575

1600

5

6

7

8

9

1%

Pasted on the Other Picture

This slide ends the Cycle Design Parametric

Tutorial