cycle design parametric study gasturb 12 – tutorial 2 copyright © gasturb gmbh
TRANSCRIPT
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GasTurb 12 Main Window
For this tutorial we will consider a 2 Spool Turbofan.
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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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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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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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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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Define the Iteration
How to define an iteration is shown in the Single Cycle Tutorial
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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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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