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INTRODUCTION TO OFF DESIGN SIMULATIONS GasTurb 12 – Tutorial 3 Copyright © Joachim Kurzke.

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Presentation on theme: "INTRODUCTION TO OFF DESIGN SIMULATIONS GasTurb 12 – Tutorial 3 Copyright © Joachim Kurzke."— Presentation transcript:

1 INTRODUCTION TO OFF DESIGN SIMULATIONS GasTurb 12 – Tutorial 3 Copyright © Joachim Kurzke

2 Off-Design Simulations Let us begin with a jet engine. Select the most simple engine architecture, a Turbojet. A click on Standard Maps begins the off-design calculation. Select as Scope Performance and then click Off Design Select as Scope Performance and then click Off Design

3 Copyright © Joachim Kurzke We Need Some Data…

4 Copyright © Joachim Kurzke Off-Design Input Data Page After reading the file, the cycle design point is calculated. This happens in the background. The standard compressor and turbine maps are scaled in such a way that they fit to the cycle design point. After reading the file, the cycle design point is calculated. This happens in the background. The standard compressor and turbine maps are scaled in such a way that they fit to the cycle design point. Now we calculate the cycle design point as an off-design point Now we calculate the cycle design point as an off-design point

5 Copyright © Joachim Kurzke Off-Design Point Summary The contents of this summary page is identical to that of the cycle design point

6 Copyright © Joachim Kurzke Operating Point Details This is the Standard High Pressure Compressor Map file This is the Standard High Pressure Turbine Map file On this page those details of the operating point are presented that are not needed for a cycle design calculation.

7 Copyright © Joachim Kurzke Compressor Map The circle marks the cycle design point, the yellow square marks the off-design operating point. The circle marks the cycle design point, the yellow square marks the off-design operating point. In this special case – because we have calculated the cycle design point in off-design mode – the yellow square is inside the circle.

8 Copyright © Joachim Kurzke Turbine Map The circle marks the cycle design point, the yellow square marks the off-design operating point. The circle marks the cycle design point, the yellow square marks the off-design operating point. There are six different versions of a turbine map. The y-axis can be Pressure Ratio or Corrected Work. Here Turbine Pressure Ratio is shown over the product of Corrected Flow and Corrected Speed. There are six different versions of a turbine map. The y-axis can be Pressure Ratio or Corrected Work. Here Turbine Pressure Ratio is shown over the product of Corrected Flow and Corrected Speed.

9 Copyright © Joachim Kurzke Turbine Map Here Turbine Pressure Ratio is shown over Corrected Speed. The corrected flow is shown as contour lines in % of the maximum corrected flow in the map Here Turbine Pressure Ratio is shown over Corrected Speed. The corrected flow is shown as contour lines in % of the maximum corrected flow in the map

10 Copyright © Joachim Kurzke Turbine Map Here Turbine Pressure Ratio is shown with the same axes as a compressor map: Turbine Pressure Ratio over Corrected Mass Flow. The disadvantage of this format is that all the speed lines nearly collapse. Here Turbine Pressure Ratio is shown with the same axes as a compressor map: Turbine Pressure Ratio over Corrected Mass Flow. The disadvantage of this format is that all the speed lines nearly collapse.

11 Thermodynamic Stations Copyright © Joachim Kurzke Here you get all the details at the thermodynamic stations. The engine geometry - all the flow areas at all stations - is among the results of the cycle design point calculation. Here you get all the details at the thermodynamic stations. The engine geometry - all the flow areas at all stations - is among the results of the cycle design point calculation.

12 Off-Design Input Data Copyright © Joachim Kurzke Here you can choose whether Relative Spool Speed ZXN or Burner Exit Temperature ZT4 is given. Here you can choose whether Relative Spool Speed ZXN or Burner Exit Temperature ZT4 is given. Enter 2 to make Burner Exit Temperature an input and use 1200 for it Let us run a case with 1200 K Burner Exit Temperature. Let us run a case with 1200 K Burner Exit Temperature.

13 Copyright © Joachim Kurzke Off-Design Result The solution is found by iteration

14 Copyright © Joachim Kurzke Compressor Map Compressor operating point for T4=1200K Cycle design point

15 Copyright © Joachim Kurzke Off-Design Iteration These are the variables of the iteration. Betavalues are auxiliary coordinates in component maps. These are the estimated values of the iteration variables. If the iteration fails to converge, you can try with better estimates for the variables. Iteration targets are flow continuity between components and power balances Now let us calculate the complete sea level static operating line.

16 Copyright © Joachim Kurzke Off-Design Input Operating Line Reset to 1 and enter for the HPC Spool Speed ZXN also 1

17 Copyright © Joachim Kurzke Operating Line Input The operating line commences with the single point which was calculated before the operating line window was opened. A series of points with decreasing gas generator spool speed will be calculated. The default step size of relative spool speed is Increase the Number of Points to 20, then run the case by clicking the Operating Line button Answer No Answer No

18 Copyright © Joachim Kurzke Compressor Operating Line Here the compressor surges We will employ a handling bleed to cure that problem.

19 Copyright © Joachim Kurzke Off-Design Input Operating Line Click Controls to show the controls button group. Then click the Bleed button Enter numbers in all 3 boxes Enter numbers in all 3 boxes Re-run the operating line

20 Copyright © Joachim Kurzke Repeat the Operating Line Calc Answer this time Yes Answer this time Yes

21 Switch Automatic Bleed “On” Copyright © Joachim Kurzke Enter 1 for the second operating line, then click Run

22 Copyright © Joachim Kurzke Compressor Operating Lines With and Without Bleed With bleed the surge problem does not exist. Let us have other views on the data

23 Copyright © Joachim Kurzke The Default Plot With bleed the surge problem does not exist. However, with bleed the fuel consumption is higher…

24 Copyright © Joachim Kurzke New Picture

25 Copyright © Joachim Kurzke New Picture

26 Copyright © Joachim Kurzke T4 = f(Corrected Spool Speed) With bleed the surge problem does not exist; however, the burner exit temperature is significantly higher This slide ends the Introduction to Off-Design Simulations Tutorial This slide ends the Introduction to Off-Design Simulations Tutorial


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