Fuel Effects on Gas Turbine Combustion—Ignition, Stability, and Combustion Efficiency

1985 ◽  
Vol 107 (1) ◽  
pp. 24-37 ◽  
Author(s):  
A. H. Lefebvre
Keyword(s):  
Gas Turbine ◽  
Analytical Study ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Fuel Properties ◽  
Substantial Body ◽  
Lean Blowout ◽  
Sponsored Programs ◽  
Key Aspects ◽  
Fuel Effects

An analytical study is made of the substantial body of experimental data acquired during recent Wright-Patterson Aero Propulsion Laboratory sponsored programs on the effects of fuel properties on the performance and reliability of several gas turbine combustors, including J79-17A, J79–17C (Smokeless), F101, TF41, TF39, J85, TF33, and F100. Quantitative relationships are derived between certain key aspects of combustion, notably combustion efficiency, lean blowout limits and lean light-off limits, and the relevant fuel properties, combustor design features, and combustor operating conditions. It is concluded that combustion efficiency, lean blowout limits, and lean lightoff limits are only slightly dependent on fuel chemistry, but are strongly influenced by the physical fuel properties that govern atomization quality and spray evaporation rates.

Combustion Characteristics of Small Size Gas Turbine Combustor Fueled by Biomass Gas Employing Flameless Combustion

2007 ◽  
Author(s):  
Masato Hiramatsu ◽  
Yoshifumi Nakashima ◽  
Sadamasa Adachi ◽  
Yudai Yamasaki ◽  
Shigehiko Kaneko
Keyword(s):  
Gas Turbine ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Flameless Combustion ◽  
Engine Exhaust ◽  
Micro Gas Turbine

One approach to achieving 99% combustion efficiency (C.E.) and 10 ppmV or lower NOx (at 15%O2) in a micro gas turbine (MGT) combustor fueled by biomass gas at a variety of operating conditions is with the use of flameless combustion (FLC). This paper compares experimentally obtained results and CHEMKIN analysis conducted for the developed combustor. As a result, increase the number of stage of FLC combustion enlarges the MGT operation range with low-NOx emissions and high-C.E. The composition of fuel has a small effect on the characteristics of ignition in FLC. In addition, NOx in the engine exhaust is reduced by higher levels of CO2 in the fuel.

scholarly journals Fuel Effects on the TF30 Engine (Alternate Test Procedure)

1984 ◽  
Author(s):  
P. A. Karpovich ◽  
A. I. Masters
Keyword(s):  
Test Procedure ◽  
Engine Performance ◽  
Combustion Efficiency ◽  
Fuel Properties ◽  
Secondary Importance ◽  
Turbine Engine ◽  
Main Burner ◽  
Alternate Test ◽  
Fuel Nozzle ◽  
Fuel Effects

The objective of the Alternate Test Procedure (ATP) is to develop the capability to qualify new fuels for Navy aircraft use with a minimum of testing. The effect of fuel composition and properties on engine performance and component life has been shown to vary significantly from one engine configuration to another. The P&WA approach to the ATP has been to define fuel effects on the TF30 engine and then apply the methodology to other engines of interest to the Navy. Investigations of the TF30 conducted under the ATP Program and other Navy and Air Force Contracts have produced one of the most complete fuel effect characterizations available for any gas turbine engine. Major fuel effects which have been quantified are the relationships of lubricity to main fuel control reliability, viscosity and volatility to main burner and augmentor ignition limits, and hydrogen content to smoke and combustor life. The effects of fuel properties and composition on combustion efficiency and elastomeric seal life were found to be of secondary importance. Remaining uncertainties are the effects of fuel properties on turbine life and fuel nozzle fouling rate.

Fuel Effects on the TF30 Engine (Alternate Test Procedure)

1985 ◽  
Vol 107 (3) ◽  
pp. 769-774
Author(s):  
P. A. Karpovich ◽  
A. I. Masters
Keyword(s):  
Test Procedure ◽  
Engine Performance ◽  
Combustion Efficiency ◽  
Fuel Properties ◽  
Secondary Importance ◽  
Turbine Engine ◽  
Main Burner ◽  
Alternate Test ◽  
Fuel Nozzle ◽  
Fuel Effects

The objective of the Alternate Test Procedure (ATP) is to develop the capability to qualify new fuels for Navy aircraft use with a minimum of testing. The effect of fuel composition and properties on engine performance and component life has been show to vary significantly from one engine configuration to another. The P&WA approach to the ATP has been to define fuel effects on the TF30 engine and then apply the methodology to other engines of interest to the Navy. Investigations of the TF30 conducted under the ATP Program and other Navy and Air Force Contracts have produced one of the most complete fuel effect characterizations available for any gas turbine engine. Major fuel effects which have been quantified are the relationships of lubricity to main fuel control reliability, viscosity and volatility to main burner and augmentor ignition limits, and hydrogen content to smoke and combustor life. The effects of fuel properties and composition on combustion efficiency and elastomeric seal life were found to be of secondary importance. Remaining uncertainties are the effects of fuel properties on turbine life and fuel nozzle fouling rate.

Preliminary design and performance analysis of a low emission aero-derived gas turbine combustor

2013 ◽  
Vol 117 (1198) ◽  
pp. 1249-1271 ◽  
Author(s):  
B. Khandelwal ◽  
A. Karakurt ◽  
V. Sethi ◽  
R. Singh ◽  
Z. Quan
Keyword(s):  
Gas Turbine ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Gas Turbine Combustor ◽  
Detailed Method ◽  
Low Emission ◽  
Heat Shields ◽  
Lean Fuel ◽  
Reduce Emissions ◽  
And Performance

Abstract Modern gas turbine combustor design is a complex task which includes both experimental and empirical knowledge. Numerous parameters have to be considered for combustor designs which include combustor size, combustion efficiency, emissions and so on. Several empirical correlations and experienced approaches have been developed and summarised in literature for designing conventional combustors. A large number of advanced technologies have been successfully employed to reduce emissions significantly in the last few decades. There is no literature in the public domain for providing detailed design methodologies of triple annular combustors. The objective of this study is to provide a detailed method designing a triple annular dry low emission industrial combustor and evaluate its performance, based on the operating conditions of an industrial engine. The design methodology employs semi-empirical and empirical models for designing different components of gas turbine combustors. Meanwhile, advanced DLE methods such as lean fuel combustion, premixed methods, staged combustion, triple annular, multi-passage diffusers, machined cooling rings, DACRS and heat shields are employed to cut down emissions. The design process is shown step by step for design and performance evaluation of the combustor. The performance of this combustor is predicted, it shows that NO x emissions could be reduced by 60%-90% as compared with conventional single annular combustors.

Exploration of Compact Combustors for Reheat Cycle Aero Engine Applications

2006 ◽  
Author(s):  
J. Zelina ◽  
D. T. Shouse ◽  
J. S. Stutrud ◽  
G. J. Sturgess ◽  
W. M. Roquemore
Keyword(s):  
Gas Turbine ◽  
Temperature Rise ◽  
Gas Turbines ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Combustion System ◽  
Turbine Engine ◽  
Lean Blowout ◽  
Power Extraction ◽  
Wide Range

An aero gas turbine engine has been proposed that uses a near-constant-temperature (NCT) cycle and an Inter-Turbine Burner (ITB) to provide large amounts of power extraction from the low-pressure turbine. This level of energy is achieved with a modest temperature rise across the ITB. The additional energy can be used to power a large geared fan for an ultra-high bypass ratio transport aircraft, or to drive an alternator for large amounts of electrical power extraction. Conventional gas turbines engines cannot drive ultra-large diameter fans without causing excessively high turbine temperatures, and cannot meet high power extraction demands without a loss of engine thrust. Reducing the size of the combustion system is key to make use of a NCT gas turbine cycle. Ultra-compact combustor (UCC) concepts are being explored experimentally. These systems use high swirl in a circumferential cavity about the engine centerline to enhance reaction rates via high cavity g-loading on the order of 3000 g’s. Any increase in reaction rate can be exploited to reduce combustor volume. The UCC design integrates compressor and turbine features which will enable a shorter and potentially less complex gas turbine engine. This paper will present experimental data of the Ultra-Compact Combustor (UCC) performance in vitiated flow. Vitiation levels were varied from 12–20% oxygen levels to simulate exhaust from the high pressure turbine (HPT). Experimental results from the ITB at atmospheric pressure indicate that the combustion system operates at 97–99% combustion efficiency over a wide range of operating conditions burning JP-8 +100 fuel. Flame lengths were extremely short, at about 50% of those seen in conventional systems. A wide range of operation is possible with lean blowout fuel-air ratio limits at 25–50% below the value of current systems. These results are significant because the ITB only requires a small (300°F) temperature rise for optimal power extraction, leading to operation of the ITB at near-lean-blowout limits of conventional combustor designs. This data lays the foundation for the design space required for future engine designs.

Steady and Dynamic Performance and Emissions of a Variable Geometry Combustor in a Gas Turbine Engine

2002 ◽  
Author(s):  
Y. G. Li ◽  
R. L. Hales
Keyword(s):  
Gas Turbine ◽  
Dynamic Performance ◽  
Flame Temperature ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Variable Geometry ◽  
Turbofan Engine ◽  
Turbine Engine ◽  
Control Schemes ◽  
Fuel Staging

One of the remedies to reduce the major emissions production of nitric oxide (NOx), carbon monoxide (CO) and unburned hydrocarbon (UHC) from conventional gas turbine engine combustors at both high and low operating conditions without losing its performance and stability is to use variable geometry combustors. This type of combustor configuration provides the possibility of dynamically controlling the airflow distribution of the combustor based on its operating conditions and therefore controlling the combustion in certain lean burn conditions. Two control schemes are described and analyzed in this paper: both are based on airflow control with variable geometry, the second including fuel staging. A model two-spool turbofan engine is chosen in this study to test the effectiveness of the variable geometry combustor and control schemes. The steady and dynamic performance of the turbofan engine is simulated and analyzed using an engine transient performance analysis code implemented with the variable geometry combustor. Empirical correlations for NOx, CO and UHC are used for the estimation of emissions. Some conclusions are obtained from this study: • With variable geometry combustors significant reduction of NOx emissions at high operating conditions and CO and UHC at low operating condition is possible; • Combustion efficiency and stability can be improved at low operating conditions, which is symbolized by the higher flame temperature in the variable geometry combustor; • The introduced correlation between non-dimensional fuel flow rate and air flow ratio to the primary zone is effective and simple in the control of flame temperature; • Circumferential fuel staging can reduce the range of air splitter movement in most of the operating conditions from idle to maximum power and have the great potential to reduce the inlet distortion to the combustor and improve the combustion efficiency; • During transient processes, the maximum moving rate of the hydraulic driven system may delay the air splitter movement but this effect on engine combustor performance is not significant.

Real-Time Prediction of Incipient Lean Blowout in a Partially Premixed, Liquid-Fueled Gas Turbine Combustor

2007 ◽  
Author(s):  
Tongxun Yi ◽  
Ephraim J. Gutmark
Keyword(s):  
Real Time ◽  
Gas Turbine ◽  
Flame Structure ◽  
Rayleigh Distribution ◽  
Operating Conditions ◽  
Statistical Characteristics ◽  
Lean Blowout ◽  
Time Prediction ◽  
Two Indices ◽  
Partially Premixed

The present paper addresses real-time prediction of incipient lean blowout (LBO) in partially premixed, liquid-fueled gas turbine combustors. Near-LBO combustion is characterized by the “intensified” low-frequency combustion oscillations, typically below 30 Hz. Two indices, namely the normalized chemiluminescence RMS and the normalized cumulative duration of LBO precursor events, are recommended for LBO prediction. Both indices are associated with the statistical characteristics of the flame structure, which changes from the normal distribution to the Rayleigh distribution at the approach of LBO. Both indices change little within a large range of equivalence ratios and start to shoot up only when LBO is approached. To use the two indices for LBO prediction, one needs to perform a detailed a priori LBO mapping under simulated engine operating conditions. However, the mapping can be done without running the engines very close to LBO.

Combination of 1D Code and CFD for Performance Analysis of a Silo Type Gas Turbine Combustor

2010 ◽  
Author(s):  
N. Rasooli ◽  
S. Besharat Shafiei ◽  
H. Khaledi
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Mass Distribution ◽  
Gas Turbines ◽  
Pressure Loss ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Empirical Correlations ◽  
Combustion Chambers ◽  
Cfd Simulations

Whereas Gas Turbines are the most important producers of Propulsion and Power in the world and with attention to the importance of combustion chamber as one of the three basic components of Gas Turbine, various activities in different levels have been done on this component. Because of the environmental limitations and laws related to the pollutants such as NOx and CO, Lean Premixed Combustion Chambers are specially considered in gas turbine industries. This study is part of a Multi-Layer simulation of the whole gas turbine cycle in MPG Company. In this work, the combination of a general 1D code and CFD is used for deriving appropriate performance curves for a 1D and 0D gas turbine design, off-design and dynamic cycle code. This 1D code is a general code which has been developed for different combustion chambers; annular, can-annular, can type and silo type combustion chambers. The purpose of generating this 1D code is the possibility of fast analysis of combustors in different operating conditions and reaching required outputs. This 1D code is a part of a general simulation 1D code for gas turbine and was used for a silo type combustor performance prediction. This code generates required quantities such as pressure loss, exit temperature, liner temperature and mass distribution through the combustion chamber. Mass distribution and pressure loss are analyzed and determined with an electrical analogy. Results derived from 1D code are validated with empirical data available for different combustors. There is appropriate agreement between these experimental and analytical results. Drag coefficients for liner holes are available from experimental data and for burner are calculated as a curve with CFD simulations. What differs this code from other 1D codes for gas turbine combustors is the advantage of using combustion efficiencies evolved from numerical simulation results in different loads. These efficiencies are determined with CFD simulations and are available as maps and inserted into the gas temperature calculation algorithm of 1D code. In other 1D codes in this field, empirical correlations are used for combustion efficiency determination. Combustion efficiency curves for design and off-design conditions in this study are achieved by 2D and 3D simulation of combustion chamber with application of EBU/Finite Rate model and 8 step reactions of CH4 burning. Diffusion flame in low loads and premixed flame in high loads are considered. Flame stability and Lean Blow Out charts are evolved from CFD simulation and Heat transfer is applied with empirical correlations.

Prediction of Gas Turbine Afterburner Performance Using CFD for Different Operating Conditions and Reheat Strength

2017 ◽  
Author(s):  
Darshan Kattegollahalli Shivakumar ◽  
Ganesan Sabbani ◽  
Gursharanjit Singh ◽  
Purushothama Harthi Revanasiddappa
Keyword(s):  
Gas Turbine ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Reacting Flow ◽  
Current Trends ◽  
Discharge Temperature ◽  
Computational Fluid Dynamics Cfd ◽  
Internal Aerodynamics ◽  
Low Performance

A gas turbine afterburner is required to operate under severe conditions of pressure and temperature to meet the design requirements of next generation gas turbine engines. This fact, coupled with the current trends towards higher turbine discharge temperature and the requirement for satisfactory operation over extended fuel/air ratios and flight maps call for greater understanding of the internal aerodynamics for improving thrust developed by the afterburner. The present work focuses on prediction of performance of a practical afterburner for different altitude conditions and reheat strengths (i.e., fuel-air ratios) using Computational Fluid Dynamics (CFD) simulations. Combustion efficiency and thrust boost at these conditions have been predicted. The reacting flow field has been analyzed and changes suggested for improving thrust at low performance points.

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