Effect of GTL-Like Jet Fuel Composition on GT Engine Altitude Ignition Performance: Part I—Combustor Operability

Author(s):  
Darren Fyffe ◽  
John Moran ◽  
Kumaran Kannaiyan ◽  
Reza Sadr ◽  
Ali Al-Sharshani

The current fuel used in aviation turbines is kerosene, and is tightly controlled to a well defined specification. The past 50 years of simultaneous development between the aviation turbine and kerosene jet fuel has led to the fuel specification. The design of the combustion system has also been developed with this fuel chemistry and specification. In the past 5 years, there has been a ground swell of interest in alternative fuels for aviation, where the fuels can be made from a variety of feedstocks and processes. The chemistry and composition of species within future alternative fuels will change from the current kerosene jet fuel specifications; therefore research has been carried out looking at the effects of some of the fundamental component species that will be found in potential future fuels. The gas turbine combustion ignition and stability characteristics were studied while fuelled by a series of gas-to-liquid (GTL) Synthetic Paraffinic Kerosene (SPK)-type fuels by measurement of the successful ignition and flame stability regimes at realistic altitude temperatures and pressures. The combustor under test was a multi-sector representation of an advanced gas turbine combustor and fuel injector. Tests were conducted on the Rolls-Royce plc TRL3 (Technology Readiness Level) sub-atmospheric altitude ignition facility in Derby, UK. The facility was operated at simulated altitude conditions of 6 and 8 psi combustor inlet pressure with corresponding air and fuel temperatures to represent combustor conditions following flame-out during high altitude cruise. The GTL SPK-type fuels were selected to generate a pseudo-Design of Experiments (DoE) matrix in which the iso- to normal-paraffin ratio, cyclic paraffin content, and carbon number range were varied to isolate the effects of each. Tests were conducted at combinations of air mass flow rate and fuel-air ratio necessary to map the regimes of successful ignition and flame stability. All fuels indicated little or no deterioration to the weak boundary of the ignition regime, nor the weak extinction limits, within the scatter of the experimental method. Evidence was found that a commercial GTL SPK, as well as one of the DoE blends, may have greater ignition performance at simulated altitude conditions. Further testing at higher TRL levels is recommended to confirm this finding. The test programme was supported by DLR, German Aerospace Centre, through high-speed diagnostic imaging of the ignition process, including OH* and CH* chemi-luminescence measurements, which is the subject of a separate complementary paper.

2019 ◽  
Vol 22 (6) ◽  
pp. 8-16
Author(s):  
Sh. Ardeshiri

The current development trend of global civil aviation is the growth of passenger and freight traffic, which entails the consumption of jet fuel. Under these conditions, increasing the efficiency of jet fuel used is of great importance. Global energy consumption is constantly growing, and, first of all, the question of diversification of oil resources arises, resources from which the bulk of motor fuels is produced. Other types of raw energy sources (natural gas, coal, bio-mass) currently account for only a small part. However, an analysis of the development of jet fuels indicates that work is underway to obtain these from other sources of raw materials, especially bio-fuels. Much attention is given to obtaining bio-fuels from renewable sources – such as algae. The issue of the mass transition of civil aviation to alternative fuels is complex and requires the solution of intricate technical as well as economic issues. One of these is the assessment of the impact of new fuels on GTE performance. It is important to give an objective and quick assessment of the use of various types of fuels on the main characteristics of the engine – i.e., throttle and high-speed characteristics. In this case, it is necessary to take into account chemical processes in the chemical composition of new types of fuel. To assess the effect of fuels on the characteristics of a gas turbine engine, it is proposed to use a mathematical model that would take into account the main characteristics of the fuel itself. Therefore, the work proposes a mathematical model for calculating the characteristics of a gas turbine engine taking into account changes in the properties of the fuel itself. A comparison is made of the percentage of a mixture of biofuels and JetA1 kerosene, as well as pure JetA1 and TC-1 kerosene. The calculations, according to the proposed model, are consistent with the obtained characteristics of a gas turbine engine in operation when using JetA1 and TC-1 kerosene. Especially valuable are the obtained characteristics of a gas turbine engine depending on a mixture of biofuel and kerosene. It was found that a mixture of biofuel and kerosene changes the physicochemical characteristics of fuel and affects the change in engine thrust and specific fuel consumption. It is shown that depending on the obtained physicochemical properties of a mixture of biofuel and kerosene, it is possible to increase the fuel efficiency and environmental friendliness of the gas turbine engines used.


Author(s):  
Greg S. Jackson ◽  
Shahrokh Etemad ◽  
Hasan Karim ◽  
William C. Pfefferle

The provision of an ignition source in the central region of a liquid-fired combustor reduces the requirement for wide spray angles, rich primary zones, and their associated performance drawbacks such as high levels of soot and NOx formation and high liner wall temperatures. Various ignition devices have been considered for providing centrally located ignition sources. The current paper presents a study of one alternative concept — the integral catalytic torch ignitor/injector — as a means for providing both combustor light-off and enhanced flame stability in the combustor primary zone. An integral catalytic torch in a fuel injector offers the potential to significantly improve ignition arid flame stability and thus the opportunity to operate combustor primary zones at leaner conditions, which may improve emissions, pattern factor, and combustor liner durability. This paper presents computational and experimental results for a conventional liquid-fired combustor with the addition of a catalytic torch (replacing the pilot pressure atomizer) down the centerline of an air-blast fuel injector. The benefits of a lean primary zone with an integral catalytic torch/injector were investigated both computationally and experimentally by comparing combustor performance with standard and successively leaner primary zones. Pattern factor and emissions are compared with different primary zone jet configurations to observe if the central torch can enhance the operability of leaner primary zones in conventional combustor geometries. The experimental and computational results suggest that the integral catalytic torch can provide more than adequate ignition capabilities with improved combustor emissions when it is combined with a relatively lean operating primary zone.


Author(s):  
Nagaraja S. Rudrapatna ◽  
Richard R. Bohman ◽  
Jonathan K. Anderson ◽  
Rudolph Dudebout ◽  
Richard Hausen

Jet fuel flowing through the fuel injector is atomized and then mixed with high temperature compressed air flowing through the swirler to create a combustible mixture inside a gas turbine combustor. Individual geometric and flow features are carefully tuned at a component level to deliver optimum combustion performance. In a critical interface such as the fuel injector and swirler, manufacturing tolerances not only have an impact on combustor performance and operability but also on durability, as the relative position of the fuel injector to the swirler significantly impacts the swirler temperature. This paper studies the influence of manufacturing tolerances on component assembly and the resulting impact on swirler temperature. The oxidation damage mechanism of the swirler is used as a measure to assess swirler durability. A Pareto chart of the effect of manufacturing tolerances on metal temperature is used to highlight the key influencing parameters. Probability distribution associated with manufacturing tolerances is gathered with Monte Carlo simulation to guide the design.


1981 ◽  
Vol 103 (1) ◽  
pp. 34-42 ◽  
Author(s):  
J. R. Shekleton

The Radial Engine Division of Solar Turbines International, an Operating Group of International Harvester, under contract to the U.S. Army Mobility Equipment Research & Development Command, developed and qualified a 10 kW gas turbine generator set. The very small size of the gas turbine created problems and, in the combustor, novel solutions were necessary. Differing types of fuel injectors, combustion chambers, and flame stabilizing methods were investigated. The arrangement chosen had a rotating cup fuel injector, in a can combustor, with conventional swirl flame stabilization but was devoid of the usual jet stirred recirculation. The use of centrifugal force to control combustion conferred substantial benefit (Rayleigh Instability Criteria). Three types of combustion processes were identified: stratified and unstratified charge (diffusion flames) and pre-mix. Emphasis is placed on five nondimensional groups (Richardson, Bagnold, Damko¨hler, Mach, and Reynolds numbers) for the better control of these combustion processes.


1994 ◽  
Vol 116 (4) ◽  
pp. 727-732 ◽  
Author(s):  
R. J. Nichols

Development of vehicles to operate on nonpetroleum fuels began in earnest in response to the energy shocks of the 1970s. While petroleum will remain the predominant transportation fuel for a long time, petroleum supplies are finite, so it is not too soon to begin the difficult transition to new sources of energy. In the past decade, composition of the fuel utilized in the internal combustion engine has gained recognition as a major factor in the control of emissions from the tailpipe of the automobile and the rate of formation of ozone in the atmosphere. Improvements in air quality can be realized by using vechicles that operate on natural gas, propane, methanol, ethanol, or electricity, but introduction of these alternative fuel vehicles presents major technical and economic challenges to the auto industry, as well as the entire country, as long as gasoline remains plentiful and inexpensive.


Author(s):  
Pablo Diaz Gomez Maqueo ◽  
Philippe Versailles ◽  
Gilles Bourque ◽  
Jeffrey M. Bergthorson

This study investigates the increase in methane and biogas flame reactivity enabled by the addition of syngas produced through fuel reforming. To isolate thermodynamic and chemical effects on the reactivity of the mixture, the burner simulations are performed with a constant adiabatic flame temperature of 1800 K. Compositions and temperatures are calculated with the chemical equilibrium solver of CANTERA® and the reactivity of the mixture is quantified using the adiabatic, freely-propagating premixed flame, and perfectly-stirred reactors of the CHEMKIN-Pro® software package. The results show that the produced syngas has a content of up to 30 % H2 with a temperature up to 950 K. When added to the fuel, it increases the laminar flame speed while maintaining a burning temperature of 1800 K. Even when cooled to 300 K, the laminar flame speed increases up to 30 % from the baseline of pure biogas. Hence, a system can be developed that controls and improves biogas flame stability under low reactivity conditions by varying the fraction of added syngas to the mixture. This motivates future experimental work on reforming technologies coupled with gas turbine exhausts to validate this numerical work.


2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Sz. Tomasek ◽  
Z. Varga ◽  
A. Holló ◽  
N. Miskolczi ◽  
J. Hancsók

AbstractThe harmful effects of aviation can only be reduced by using alternative fuels with excellent burning properties and a high hydrogen content in the constituent molecules. Due to increasing plastic consumption the amount of the plastic waste is also higher. Despite the fact that landfill plastic waste has been steadily reduced, the present scenario is not satisfactory. Therefore, the aim of this study is to produce JET fuel containing an alternative component made from straight-run kerosene and the waste polyethylene cracking fraction. We carried out our experiments on a commercial NiMo/Al


1997 ◽  
Vol 119 (1) ◽  
pp. 34-44 ◽  
Author(s):  
N. K. Rizk ◽  
J. S. Chin ◽  
M. K. Razdan

Satisfactory performance of the gas turbine combustor relies on the careful design of various components, particularly the fuel injector. It is, therefore, essential to establish a fundamental basis for fuel injection modeling that involves various atomization processes. A two-dimensional fuel injection model has been formulated to simulate the airflow within and downstream of the atomizer and address the formation and breakup of the liquid sheet formed at the atomizer exit. The sheet breakup under the effects of airblast, fuel pressure, or the combined atomization mode of the airassist type is considered in the calculation. The model accounts for secondary breakup of drops and the stochastic Lagrangian treatment of spray. The calculation of spray evaporation addresses both droplet heat-up and steady-state mechanisms, and fuel vapor concentration is based on the partial pressure concept. An enhanced evaporation model has been developed that accounts for multicomponent, finite mass diffusivity and conductivity effects, and addresses near-critical evaporation. The presents investigation involved predictions of flow and spray characteristics of two distinctively different fuel atomizers under both nonreacting and reacting conditions. The predictions of the continuous phase velocity components and the spray mean drop sizes agree well with the detailed measurements obtained for the two atomizers, which indicates the model accounts for key aspects of atomization. The model also provides insight into ligament formation and breakup at the atomizer exit and the initial drop sizes formed in the atomizer near field region where measurements are difficult to obtain. The calculations of the reacting spray show the fuel-rich region occupied most of the spray volume with two-peak radial gas temperature profiles. The results also provided local concentrations of unburned hydrocarbon (UHC) and carbon monoxide (CO) in atomizer flowfield, information that could support the effort to reduce emission levels of gas turbine combustors.


Author(s):  
Alexander Kolpakov ◽  
Austin Marie Sipiora ◽  
Caley Johnson ◽  
Erin Nobler

This case study presents findings from an analysis of the emergency preparation and response for Hurricane Irma, the most recent hurricane impacting the Tampa Bay region. The Tampa Bay region, in particular, is considered one of the most vulnerable areas in the United States to hurricanes and severe tropical weather. A particular vulnerability stems from how all petroleum fuel comes to the area by marine transport through Port Tampa Bay, which can be (and has been in the past) impacted by hurricanes and tropical storms. The case study discussed in this paper covers previous fuel challenges, vulnerabilities, and lessons learned by key Tampa Bay public agency fleets during the past 10 years (mainly as a result of the most recent 2017 Hurricane Irma) to explore ways to improve the area’s resilience to natural disasters. Some of the strategies for fuel-supply resiliency include maintaining emergency fuel supply, prioritizing fuel use, strategically placing the assets around the region to help with recovery, investing in backup generators (including generators powered by alternative fuels), planning for redundancies in fuel supply networks, developing more efficient communication procedures between public fleets, hurricane preparedness-planning, and upgrading street drainage systems to reduce the threat of local flooding.


Author(s):  
C. A. Arana ◽  
B. Sekar ◽  
M. A. Mawid

This paper describes an analytical and experimental investigation to obtain the thermoacoustic response of a demonstrator gas turbine engine combustor. The combustor acoustic response for two different fuel injector design configurations was measured. It was found that the combustor maximum peak to peak pressure fluctuations were 0.6 psi to 2 psi for configuration A and B respectively. Based on the measured acoustic response, another experimental investigation was conducted to identify the design features in configuration B that caused the increase in the acoustic response. The data showed that by changing the fuel injector swirler’s vane to inner passage discharge area ratio, the engine acoustic response could be lowered to an acceptable level. A simplified analytical model based on the lumped-parameter approach was then developed to investigate the effect of geometrical changes upon the engine response. The analytical model predicted the fuel injector/swirlers acoustic response as a function of the swirlers inner passage discharge area ratio and frequency. The predictions were consistent with the experimental observations, in particular, it was predicted that as the area ratio was increased, the system reactance was decreased and as a result the system changed from a damping to an amplifying system.


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