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CONVENTIONAL AND MODEL BASED TEST ANALYSIS

GasTurb 12

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GasTurb 12 Main Window

For this tutorial we will use a 2 Spool Turboshaft.

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We Need Some Data

Select the engine model

Open the engine model

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Test Analysis Input Data Page

Switch Test Analysis on and have a look at the Stations Window if

you are not sure about where the measurements are taken.

Then calculate the Design Point.

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Test Analysis Result

These are the measured data given on the test

analysis page…

These are the measured data given on the test

analysis page…

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Design Point Input Data Page

Note that the data on the Test Analysis Input Page are not the only ones

affecting the test analysis. All the other cycle input data, including the

secondary air system, must be known for a precise result.

Some input quantities, such as compressor and turbine efficiency,

pressure ratio and burner exit temperature, are not visible because these data are results in test analysis

mode.

What if W2Rstd is not measured

and thus not known?

You can find W2Rstd if you have measured data for T45 or T5. If these values are not known then you may know the HP turbine flow capacity

W41Rstd.

Iterate W2Rstd in such a way that the

calculated T5 is equal to the

measured T5, for example.

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Two Test Analysis Methods

Conventional Test Analysis– Calculates the Cycle Employing

the Measured Data– Some Knowledge About the

Engine is Required• Secondary Air System

– The Test Analysis Runs in Cycle Design Mode

– The Test Analysis Result is Difficult to Judge:

• Is Compressor Efficiency Poor Because the Compressor is Damaged or Because it Runs at Aerodynamic Overspeed?

Model Based Test Analysis– Compares the Measurements

with a Model of the Engine– A Full Thermodynamic Model is

the Basis– The Test Analysis Runs in Off-

Design Mode– Factors to the Component

Performance are Found Which Make the Model Agree With the Measured Data

– The Test Analysis Result is the Deviation Between the Model and the Engine

• The Result for Compressor Efficiency is Independent of the Operating Point: Better or Worth than Expected

What we have done up to now was a Conventional Test Analysis. Now we go for

the Model Based Analysis, also called Analysis by Synthesis (AnSyn)

GasTurb 12 Main Window

Now we will use a Geared Mixed Turbofan

In calculation modeOff Design

With Standard Maps

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The file opening menu will appear automatically, read the file

Demo_mgtf.cgm

After reading the data, the cycle design point will be calculated in the background and then the Off-Design

Input Window opens.

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Off Design Input Window

Select Test Analysis and

switch to the Test Analysis View

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Test Data Input

Example test data are store

in the file.

Click here to run the test analysis

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AnSys Result

A value of 1 (or 0K respectively) for the AnSyn

Factors in this column means perfect line-up of the

measurement with the model.

The HPC Efficiency Factor is around 1.09, that means

the HPC performs better than expected.

Click here to see the whole cycle

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AnSys Result

This are the measured data

given on the test data page.

Remember:the overall

compression pressure ratio P3/P2 is 35.67

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Correction to Nominal Conditions

Now run the model - with the AnSyn Factors applied -at the same corrected spool speed

as tested. This yields pressure ratios that are very close to those during

the test.

Click here to run the ISA Correction

Change Delta T from ISA to 0

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Data Corrected to Nominal Conditions

Remember:the overall

compression pressure ratio

P3/P2 in the test was 35.67

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Sensitivity to Measurement Errors

Sensitivity to Measurement Errors

can be calculated automatically

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Sensitivity to Measurement ErrorsNeed

Explanations?

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Flexibility of AnSyn

Here you can choose theCore Flow

Analysis Method.

Core Flow Analysis MethodsIterate Bypass Ratio (Core Flow) in such a way that one of the following conditions is fulfilled:• W41Rstd = given W41Rstd

(HP Turbine Capacity)• W45Rstd = given W45Rstd

(LP Turbine Capacity)• T45 = Measured T45• T5 = Measured T5

What if no measured mass

flow W2 is available?

Define an Iteration

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Defining an Iteration

Assume that the fan model is correct, for example. That means the Fan Flow Factor is equal to 1

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Calculate…This is now the start

value for the iteration.

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Mass Flow W2 Found by Iteration

Found by Iteration

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Flexibility of AnSyn

What if there are additional

measured data to be considered ?

Employ these placeholders for input of

the data…

… and use optionally an

iteration to bring the measurement in line with the Composed

Values.

This slide ends the Conventional and Model Based Test Analysis Tutorial