Transcript GasTurb 12: Cycle Design Parametric Study

GasTurb 12 – Tutorial 2
Copyright © Joachim Kurzke
CYCLE DESIGN PARAMETRIC STUDY
GasTurb 12 Main Window
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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.
Parameter Selection
Click here to run all
cases
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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.
Graphical Output
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Picture 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)
Single Parameter
Plot With a Single Y-Axis
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This black square
marks the Cycle
calculated before
beginning the
Parametric study
We go back to the previous
window and select a new view
(New Picture) of the data created
in the Parametric Study
Single Parameter
A Plot With Several Y-Axes
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Select the number of yaxes first!
We will employ several
y-axes
Drag four parameters to the
respective y-axis boxes. Then
click Draw y=f(x)
Plot With Four Y-Axes
On each y-axis there is
a different symbol.
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Close this window to go
for a new Parametric
study.
This line belongs to the
LPT Pressure Ratio
axis – the symbols on
the line and on the axis
are the same.
Parameter Selection
Adding a Second Parameter
Click this tab for
specifying the
second parameter
Use these
numbers
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Click here to run all
cases
This is the Burner Exit Temperature of the cycle
calculated before this Parametric study.
We employ Burner Exit Temperature
as the second parameter
The Default Plot
No Contour Lines
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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
Getting the Detailed Output for any Parameter Combination
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Now we will add more
information to the
picture. Click
New Picture
SELECT
Double click (in GasTurb) to
select T4=1425 and
HPC Pressure Ratio = 9
Contour Parameter Selection
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An option: Click
to sort the
property names
alphabetically
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Plot with Contours
Editing Contours
Edit the numbers:
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Click to apply the
new settings
Lowest Contour Value = 0.435
Step Size = 0.005
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The Customized Plot
Let us add now a
design limit for
T45 of 1200 K
to the carpet.
Showing Design Limits
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Example: Add a Boundary for T45>1200K
Upper or
lower limit
Showing Design Limits
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Next we go for
another
New Picture
Specific Fuel Consumption (SFC) as a Function of
HPT Pressure Ratio
The disadvantage of this plot is that
there is no information about
HPT Pressure Ratio anymore.
We go for
another
New Picture
To correct for that we add contour
lines for HPT
Pressure
Sometimes
the
lines areRatio.
overlapping and the plot is
difficult to read
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Changing the Layout
resolves this problem
Specific Fuel Consumption (SFC) as a Function of
Ideal Jet Velocity Ratio V18/V8
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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
De-Activating the Iteration
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Click to de-activate the iteration
Now run the
Parametric study
again
Outer Fan Pressure Ratio = 1.8
Iteration is De-Activated
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Adjust the scales to make the
picture comparable to the picture
with the optimized Outer Fan
Pressure Ratio.
Outer Fan Pressure Ratio = 1.8
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Repeat clicking this
button until no parameter
values are shown
Outer Fan Pressure Ratio = 1.8
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Select a color
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The Overlay on the Clipboard
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Pasted on the Other Picture
This slide ends the
Cycle Design Parametric
Tutorial