performance analysis of twin-spool water injected gas

1

LABORATORY OF THERMAL TURBOMACHINESNATIONAL TECHNICAL UNIVERSITY OF ATHENS

Performance Analysis of Twin-Spool Water Injected Gas Turbines using Adaptive Modeling

Performance Analysis of Twin-Spool Water Injected GasTurbine using Adaptive Modeling

Laboratory of Thermal TurbomachinesNational Technical University of Athens

I. Roumeliotis K. Mathioudakis N. Aretakis

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Performance Analysis of TwinPerformance Analysis of Twin--Spool Water injected Gas Spool Water injected Gas Turbines using Adaptive ModelingTurbines using Adaptive Modeling

§Constitution of a Performance Model

§Elements of Adaptive Modeling

§Implementation to an Engine

§Study of Gas Turbine Behavior

§Components Behavior

§Water Injection Effect on Engine Diagnostics

§Conclusions

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Constitution of a Performance ModelConstitution of a Performance Model

Desire to represent the performance of an individual engine as accurately as possible in all situations

W.I.

2

W.I.

1 W.I.

4

W.I.

5

4










§Conclusions

5



Elements of Adaptive modelsElements of Adaptive models

Actual Engine

Engine Model

Do data match?

Adjust model Parametersthrough MFs

Measured variables / Available Data

Predicted variables

6



The meaning of Modification factorsThe meaning of Modification factors

Transformation of component performance mapsPr

essu

re R

atio

Corrected Mass Flow

krefp

kpk x

xf

,,

,=

kpx ,

krefpx ,,

: Actual value for parameter

: Reference value for parameter

7










§Conclusions

8



Implementation to a selected Engine

§5 stage LPC

§14 stage HPC with 6 V.G.S.§2 stage air – cooled HPT

§5 stage LPT

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Engine Data

§Data for the Nominal Operating Conditions

§Thermodynamic Analysis

§Create Components Initial Characteristics

Adaptation

§Initial Adaptation to Nominal Operating Conditions

§Acquire Operating Data Points

§Determination of MFs according to Available Data

§Determination of new Components Characteristics

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30

32

34

36

38

40

42

44

46

48

50

0 10 20 30 40Ambient Temp. oC

Sha

ft P

ower

(MW

)

7800

8000

8200

8400

8600

8800

9000

0 5 10 15 20 25 30 35 40Ambient Temp. oC

Shaf

t hea

t Rat

e (B

tu/k

Whr

)

Present Model

Dry dataSteam Inj. data

Water Inj. Data

Load Schedule

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§Conclusions

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Performance Prediction

Control Parameter

§Low Pressure Turbine Inlet Temperature

§Compressor Discharge Temperature (Tamb>15oC)

Test Cases

§Evaporative Cooling via Water Injection

§Intercooling via Water Injection

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Evaporative CoolingEvaporative Cooling

Operation with constant CDT results in a Slight Higher Gain in Load

0.60

0.70

0.80

0.90

1.00

1.10

1.20

0 5 10 15 20 25 30 35 40 45 50Ambient Temperature (oC)

Load

/(Loa

d)re

f

CDT constantLPTIT constantCDT constant & Ev. CoolingLPTIT constant & Ev. Cooling

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Evaporative CoolingEvaporative Cooling

Operation with constant CDT results in a Slight Higher Gain in Thermal Efficiency

0.9

0.95

1

1.05

1.1


HR

/(HR

)ref

CDT constantLPTIT constantCDT constant & Ev. CoolingLPTIT constant & Ev. Cooling

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IntercoolingIntercooling

For High Ambient Temperature operation with constant CDT results in an Important Load Gain

0.6

0.7

0.8

0.9

1

1.1

1.2


Load

/(Loa

d)re

f

CDT constantLPTIT constantCDT constant & intercoolingLPTIT constant & intercooling

water injection

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IntercoolingIntercooling

For High Ambient Temperature operation with constant CDT results in Higher Gain

0.9

0.95

1

1.05

1.1


HR

/(HR

)ref

CDT constantLPTIT constantCDT constant & intercoolingLPTIT constant & intercooling

water injection

17










§Conclusions

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Component BehaviorComponent Behavior

Tamb = 15oC, Load varies from 30 to 50 MW

Low Pressure Compressor

0.60

0.70

0.80

0.90

1.00

1.10

1.20

0.90 0.95 1.00 1.05Fraction of Design Air Flow

(πc-

1)/(π

c-1)

ref Dry

ChillingIntercoolingSteam Injection

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Component BehaviorComponent Behavior

Tamb = 15oC, Load varies from 30 to 50 MW

High Pressure Compressor

0.70

0.80

0.90

1.00

1.10

1.20

1.30

0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15Fraction of Design Air Flow

(πc-

1)/(π

c-1)

ref

DryChillingIntercoolingSteam Injection

Increasing Load

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Component BehaviorComponent BehaviorLow Pressure Compressor

Load = 45MW, Tamb varies from -10 to 50 oC

0.60

0.70

0.80

0.90

1.00

1.10

1.20

0.90 0.95 1.00 1.05Fraction of Design Air Flow

(πc-

1)/(π

c-1)

ref

DryChillingIntercoolingSteam Injection Intercooling in

Use (10oC)

Decreasing Tamb

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Component BehaviorComponent BehaviorHigh Pressure Compressor

Load = 45MW, Tamb varies from -10 to 50 oC

0.70

0.80

0.90

1.00

1.10

1.20

1.30

0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15Fraction of Design Air Flow

(πc-

1)/(π

c-1)

ref

DryChillingIntercoolingSteam Injection

Increasing Tamb

Intercooling in Use

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Component BehaviorComponent BehaviorAdditional Information obtained for operation with Water

Injection

q

π

Original

Adapted

23










§Conclusions

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f1~W

f2~np

f3~W

f4~np

f5~Δpb

f6~nb

f7~Wf8~np

f9~Wf10~np

Engine DiagnosticsEngine Diagnostics

Pictorial view of MF on engine components

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Engine DiagnosticsEngine DiagnosticsMeasurement Deviation

Intercooling with Water Injection, Ww/Winletair = 0.02

LPTIP CDP N25 CDT LPTIT EGT-1.5

-1

-0.5

0

0.5D

evia

tion

(%)

Load = ctTamb = 15oCRHamb = 30%

Monitoring Techniques based on Direct Observation of Measured Quantities may lead to erroneous conclusion if Water Injection is not taken into account

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Engine DiagnosticsEngine DiagnosticsHealth Indices Deviation

f2 f3 f4 f7 f8 f9 f10-1

0

1

2

3

4

5

6Intercooling with Water Injection (Ww/Winletair=0.02)

Monitoring Techniques based on Health Parameters may lead to erroneous conclusion if Water Injection is not taken into account

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•Using appropriate procedure it is possible to estimate the engine performance even if limited information is available

•The structure of the model gives the ability of modeling water injection at various station and using different parameters as control variables.

•Data from water Injection gives additional information for determination of component characteristics

•Water Injection must be modeled for accurate diagnosis

ConclusionsConclusions

performance analysis of twin-spool water injected gas

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