Transcript JBasile Thesis Defense - Rensselaer Polytechnic Institute

Finite Element Modeling and
Simulation of the Effect of Water
Injection on Gas Turbine Combustor
NOx Emissions and Component
Temperature
Joseph M. Basile
Master’s Thesis
11/14/2014
Professor S. Bose
Professor E. Gutierrez-Miravete
Professor N. Lemcoff
Rensselaer Polytechnic Institute
Water Injection and NOx
• Nitrous Oxides (NOx) are a byproduct of gas
turbine engine operation, and are considered
harmful pollutants
• Reducing NOx emissions is the subject of
contemporary research
• Most research focuses on methods that achieve
the greatest reduction in emissions with the least
impact to performance
• Water injection is perhaps the most studied and
most effect means of reducing NOx
• What other benefits can water injection have?
2
Water Injection
• High combustion temperature can wear or damage engine
components
• Like air cooling and high temperature coatings, liquid water
injection into the engine could protect components from heat
related damage while simultaneously reducing NOx emissions
• NOx emissions are highest when the temperature is highest
J85-GE-17A turbojet
3
Engine Modeling
• 3D model created from a description of a
research engine from University of Padova, Italy
• Engine interior from compressor outlet to turbine
inlet, including the combustion chamber, were
modeled and simulated
• A 2D axisymmetric model was created for initial
simulations
• Boundary conditions and lessons learned were
used to create a 3D model of 1/12 of engine
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2D Axisymmetric Model
Combustor
Outlet
Airflow
Region
Fuel
Injector
Combustion
Chamber
Airflow
Inlet
Water Injection Inlet
Water
Evaporation
Region
Combustion
Region
Axis of
Revolution
5
Boundary Conditions
Simulation
Backpressure
Air Flow
Fuel Pressure
Fuel Flow Rate
Water
Water Flow
Number
(Pa)
(kg/s)
(Pa)
(kg/s)
Pressure (Pa)
(kg/s)
Target
0.53
0.007261
0.013533
1
395500
0.50572
395736
0.00247
401700
0.01147
2
395000
0.5147
395736
0.0055
401700
0.01259
3
394148
0.52982
395736
0.01065
401700
0.01448
4
394148
0.53027
395400
0.00852
401700
0.01453
5
394148
0.53053
395200
0.00725
401700
0.01457
6
394148
0.53071
395200
0.00726
401500
0.01391
7
394148
0.53081
395200
0.00726
401386
0.01353
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Boundary Conditions
Simulation Values
Target Value
Линейная (Simulation Values)
Fuel Mass Flow Rate (kg/s)
0,012
0,01
y = 0,0000063393x - 2,4980335714
R² = 1,0000000000
0,008
0,006
0,004
0,002
0
395100
395200
395300
395400
395500
395600
395700
395800
Fuel Inlet Pressure (Pa)
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2D Axisymmetric Model Results
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3D Engine Model
Airflow
Region
Fuel
Injector
Airflow
Inlet
Combustion
Region
Combustion
Chamber
Combustor
Outlet
Water Injection Inlet
Water Evaporation Region
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3D Model Results
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3D Model Results
• Average Combustor Exit Temperature
– Without water injection: 1037.49 K
– With water injection: 919.054 K
• NOx Production
– Without water injection: 3.015E-5 kg/s
– With water injection: 4.564E-6 kg/s
– 84.86% reduction in NOx emissions
• Inner wall surface temperature
– Without water injection: 400-800 K
– With water injection: ~373 K
– Wall temperature of around ~370 – 380 K was maintained along
the inner wall due to the evaporation of water droplets
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Questions?
12
Backup Slides
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NOx Emissions
0,00014
NOx Mass Faction
0,00012
0,0001
0,00008
y = 1,950280E-11e1,676196E-02x
R² = 9,566537E-01
0,00006
0,00004
0,00002
0
920
922
924
926
928
930
932
934
Combustor Exit Temperature (K)
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2D Axisymmetric Wall Temp
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3D Wall Temp
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Flow Simulations - Results
Fluid Streamlines – Without
Water Injection
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Flow Simulations - Results
Fluid Temperature – Without
Water Injection
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Flow Simulations - Results
Surface Temperature – Without
Water Injection
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Flow Simulations - Results
Fluid Streamlines – With Water
Injection
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Flow Simulations - Results
Fluid Temperature – With Water
Injection
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Flow Simulations - Results
Surface Temperature – With
Water Injection
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