Numerical Study on the Characteristics of Lean Direct Injection Combustor With Elevated Fuel Temperatures

Abstract With the development of high performance gas turbine engines, the temperature before turbine is rising and it presents a serious challenge to existing thermal management. It is very attractive to use fuel as the cooling medium for gas turbine engines. For this purpose, the effects of fuel temperature on combustion characteristics are urgently needed to be understood. In this work, the characteristics of lean direct injection (LDI) combustor is simulated by changing the physical properties of fuel with different temperatures. The predictions of gas phase and droplet velocity, droplet diameter are compared well with the experiment data. The numerical results show that as fuel temperature rises, the droplet evaporation rate and mixing efficiency of fuel and air in non-reacting case is improved significantly, the spray angle, concentration and distribution profile of fuel in reacting case are enlarged as well. When fuel temperature is raised from 350K to 550K, the peak value of droplet evaporation rate at the vicinity of nozzle is increased by 26.7 times, the uniformity index downstream of the primary recirculation zone (PRZ) is increased by 2.57%, the axial length and maximum negative axial velocity of PRZ are reduced by 13% and 21%. The average temperature and NO emission at combustor outlet are increased by 1.99% and 48.15%, the mass fraction of CO is decreased by 5.45%. Besides, the number, diameter, and distribution space of droplets are decreased sharply. The formation of premixed flame and propagation of high-temperature region are promoted, the flame front is changed from a conical shape to a recessed shape. The combustion efficiency can be improved by increasing fuel temperature. The present study is expected to provide insightful information for understanding characteristics of LDI combustor with elevated fuel temperatures.

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Advanced Multi-Cup Fuel Injector Technology for Environmentally Responsible Aviation Gas Turbine Engines

Volume 4A: Combustion, Fuels and Emissions ◽

10.1115/gt2015-42703 ◽

2015 ◽

Author(s):

Erlendur Steinthorsson ◽

Adel Mansour ◽

Brian Hollon ◽

Michael Teter ◽

Clarence Chang

Keyword(s):

Gas Turbine ◽

Direct Injection ◽

Pressure Ratio ◽

Test Facility ◽

Turbine Engines ◽

Practical Implementation ◽

Gas Turbine Engines ◽

Fuel Injector ◽

Ambient Conditions ◽

Environmentally Responsible

Participating in NASA’s Environmentally Responsible Aviation (ERA) Project, Parker Hannifin built and tested multipoint Lean Direct Injection (LDI) fuel injectors designed for NASA’s N+2 55:1 Overall Pressure-Ratio (OPR) gas turbine engine cycles. The injectors are based on Parker’s earlier three-zone injector (3ZI) which was conceived to enable practical implementation of multipoint LDI schemes in conventional aviation gas turbine engines. The new injectors offer significant aerodynamic design flexibility, excellent thermal performance, and scalability to various engine sizes. The injectors built for this project contain 15 injection points and incorporate staging to enable operation at low power conditions. Ignition and flame stability were demonstrated at ambient conditions with ignition air pressure drop as low as 0.3% and fuel-to-air ratio (FAR) as low as 0.011. Lean Blowout (LBO) occurred at FAR as low as 0.005 with air at 460 K and atmospheric pressure. A high pressure combustion testing campaign was conducted in the CE-5 test facility at NASA Glenn Research Center at pressures up to 250 psi and combustor exit temperatures up to 2,033 K (3,200 °F). The tests demonstrated estimated LTO cycle emissions that are about 30% of CAEP/6 for a reference 60,000 lbf thrust, 54.8-OPR engine. This paper presents some details of the injector design along with results from ignition, LBO and emissions testing.

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Inlet Fogging of Gas Turbine Engines: Experimental and Analytical Investigations on Impaction Pin Fog Nozzle Behavior

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1808429 ◽

2006 ◽

Vol 128 (4) ◽

pp. 826-839 ◽

Cited By ~ 7

Author(s):

Mustapha A. Chaker ◽

Cyrus B. Meher-Homji ◽

Thomas Mee

Keyword(s):

Gas Turbine ◽

Evaporation Rate ◽

Climatic Conditions ◽

Turbine Engines ◽

Theoretical Studies ◽

Gas Turbine Engines ◽

The Past ◽

The Subject ◽

Evaporation Dynamics ◽

Experimental And Theoretical Studies

The inlet fogging of gas turbine engines for power augmentation has seen increasing application over the past decade. This paper provides the results of extensive experimental and theoretical studies conducted on impaction pin fog nozzles. It covers the important area of the fog plume pattern of impaction pin nozzles and examines fog-plume uniformity. The subject of sprinkle (large droplet formation) from the nozzles is also examined in detail and is shown to be nonsignificant. The effect, on evaporation rate, of ambient climatic conditions and the location of the fog nozzle with respect to the gas turbine inlet duct has been analytically and experimentally analyzed. An analytical model is used to study the evaporation dynamics of fog droplets injected in the inlet ducts. The model is validated experimentally in a wind tunnel.

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Numerical study of flows in axial compressors of aircraft gas-turbine engines

Eastern-European Journal of Enterprise Technologies ◽

10.15587/1729-4061.2018.139445 ◽

2018 ◽

Vol 4 (8 (94)) ◽

pp. 40-49

Author(s):

Ludmila Boyko ◽

Alexandr Dyomin

Keyword(s):

Gas Turbine ◽

Numerical Study ◽

Turbine Engines ◽

Gas Turbine Engines ◽

Axial Compressors

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Inlet Fogging of Gas Turbine Engines: Experimental and Analytical Investigations on Impaction Pin Fog Nozzle Behavior

Volume 2: Turbo Expo 2003 ◽

10.1115/gt2003-38801 ◽

2003 ◽

Cited By ~ 5

Author(s):

Mustapha A. Chaker ◽

Cyrus B. Meher-Homji ◽

Thomas Mee

Keyword(s):

Gas Turbine ◽

Evaporation Rate ◽

Climatic Conditions ◽

Turbine Engines ◽

Theoretical Studies ◽

Gas Turbine Engines ◽

The Past ◽

The Subject ◽

Evaporation Dynamics ◽

Experimental And Theoretical Studies

The inlet fogging of gas turbine engines for power augmentation has seen increasing application over the past decade. This paper provides the results of extensive experimental and theoretical studies conducted on impaction pin fog nozzles. It covers the important area of the fog plume pattern of impaction pin nozzles and examines fogplume uniformity. The subject of sprinkle (large droplet formation) from the nozzles is also examined in detail and is shown to be nonsignificant. The effect, on evaporation rate, of ambient climatic conditions and the location of the fog nozzle with respect to the gas turbine inlet duct has been analytically and experimentally analyzed. An Analytical model is used to study the evaporation dynamics of fog droplets injected in the inlet ducts the model is validated experimentally in a wind tunnel.

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A Comprehensive Fuel Spray Model for High Pressure Fuel Injectors

Volume 3: Combustion, Fuels and Emissions, Parts A and B ◽

10.1115/gt2008-50457 ◽

2008 ◽

Cited By ~ 1

Author(s):

Gerald J. Micklow ◽

Krishna Ankem ◽

Tarek Abdel-Salam

Keyword(s):

Experimental Data ◽

High Pressure ◽

Gas Turbine ◽

Direct Injection ◽

Combustion Process ◽

Injection Pressure ◽

Pollutant Emission ◽

Turbine Engines ◽

Gas Turbine Engines ◽

Fuel Injectors

Understanding the physics and chemistry involved in spray combustion, with its transient effects and the inhomogeneity of the spray is quite challenging. For efficient operation of both internal combustion and gas turbine engines, great insight into the physics of the problem can be obtained when a computational analysis is used in conjunction with either an experimental program or through published experimental data. The main area to be investigated to obtain good combustion begins with the fuel injection process and an accurate description of the mean diameter of the fuel particle, injection pressure, drag coefficient, rate shaping etc must be defined correctly. This work presents a methodology to perform the task set out in the previous paragraph and uses experimental data obtained from available literature to construct a semi-empirical numerical model for high pressure fuel injectors. A modified version of a multidimensional computer code called KIVA3V was used for the computations, with improved sub-models for mean droplet diameter, injection pressure, injection velocity, and drop distortion and drag. The results achieved show good agreement with the published in-cylinder experimental data for a Volkswagen 1.9 L turbo-charged direct injection internal combustion engine under actual operating conditions. It is crucial to model the spray distribution accurately, as the combustion process and the resulting temperature distribution and pollutant emission formation is intimately tied to the in-cylinder fuel distribution. The present scheme has achieved excellent agreement with published experimental data and will make an important contribution to the numerical simulation of the combustion process and pollutant emission formation in compression ignition direct injection engines and gas turbine engines.

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Influence of Fuel Jet Momentum on Characteristics of a Reverse-Cross Flow Combustor

Volume 1: Compressors, Fans and Pumps; Turbines; Heat Transfer; Combustion, Fuels and Emissions ◽

10.1115/gtindia2017-4600 ◽

2017 ◽

Cited By ~ 1

Author(s):

Shreshtha Kumar Gupta ◽

Vaibhav Arghode

Keyword(s):

Gas Turbine ◽

Fuel Injection ◽

Direct Injection ◽

Cross Flow ◽

Pollutant Emissions ◽

Turbine Engines ◽

Gas Turbine Engines ◽

Air Jet ◽

Fuel Jet ◽

Thermal Intensity

The current work is aimed towards development of high thermal intensity, low emission combustor for gas turbine engines. Employing discrete and direct injection of air and fuel in a combustion chamber and has been demonstrated to result in low pollutant emissions (NOx, CO, UHC). From our previous investigations, we found that the reverse-cross flow configuration, where air is injected from the exit end and fuel is injected in the cross flow of the injected air, results in favorable combustion and emission characteristics. Though the air jet is the dominant jet, the fuel jet can also influence the flow field, mixing and the combustion behavior inside the combustor, which is the subject of the current investigation. Here we investigate a high thermal intensity combustor relevant to gas turbine engines (at equivalence ratio of 0.8, the combustor operates at thermal intensity of 39 MW/m3-atm and heat load of 6.25 kW). Natural gas is used as the fuel and two different fuel injection diameters of 1 mm and 2 mm are investigated. This result in significantly higher (four times) fuel jet momentum from the smaller fuel injection port as compared to the larger port. From computational fluid dynamics (CFD) studies, it is observed that for the case with higher fuel jet momentum, the fuel jet deflects the air jet such that the flow pattern is significantly altered as compared to the case with lower fuel jet momentum. OH* chemiluminescece images show that the reaction zone location is significantly affected with high momentum fuel jet. NOx is reduced whereas CO is increased with higher momentum fuel jet.

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