Investigation of Reverse Flow Slinger Combustor with Jet A-1 and Methanol

Author(s):  
Abhishek Dubey ◽  
Pooja Nema ◽  
Abhijit Kushari

Abstract This paper describes experimental investigation of a Reverse Flow Slinger (RFS) combustor that has been developed in order to attain high flame stability and low emissions in gas turbine engines. The combustor employs centrifugal fuel injection through a rotary atomizer and performs flame stabilization at the stagnation zone generated by reverse flow configuration. The design facilitates entrainment of hot product gases and internal preheating of the inlet air which enhances flame stability and permits stable lean operation for low NOx. Moreover, the use of rotary atomizer eliminates the need for high injection pressure resulting in a compact and lightweight design. Atmospheric pressure combustion was performed with liquid fuels, Jet A-1 and Methanol at ultra-lean fuel air ratios (FAR) with thermal intensity of 28 - 50 MW/m3atm. Combustor performance was evaluated by analyzing the lean blowout, emissions and combustion efficiency. Test results showed high flame stability of combustor and a very low lean blowout corresponding to global equivalence ratio of around 0.1 was obtained. Sustained and stable combustion at low heat release was attained and NOx emissions as low as of 0.4 g/Kg and 0.1 g/Kg were obtained with Jet A-1 and Methanol respectively. Combustion efficiency of 55% and 90% was obtained in operation with Jet A-1 and Methanol. Performance of the combustor was significantly better with Methanol in terms of emissions and efficiency.

Author(s):  
A. F. Ali ◽  
G. E. Andrews

Flame Stability and Emission results are presented for a jet shear layer primary zone design consisting of a 90° conical flame stabiliser with a central annular vaporiser fuel injection system feeding an array of air jets. The performance with kerosene and gas oil fuels is compared with previous work with propane. The influence of the primary zone residence time or Mach number is shown to be much more significant for liquid fuels than for propane. An acceptable combustion efficiency was only achieved at a Mach number of 0.03, corresponding to 60% of the combustion air in the primary zone, provided that the pressure loss was maintained as the Mach number was reduced by using a stabiliser of higher blockage. NOx emissions with kerosene were compatible with those for propane, but for gas oil there was a significant increase in NOx.


Author(s):  
H. S. Alkabie ◽  
G. E. Andrews

Curved blade radial swirlers using all the primary air were investigated with applications to lean burning gas turbine combustor primary zones with low NOx emissions. Two modes of fuel injection were compared, central and radial swirler pássage injection for gaseous and liquid fuels. Both fuel systems produced low NOx emissions but the upstream mixing in the swirler passages resulted in ultra low NOx emissions. A 140mm diameter atmospheric pressure combustor was used with 43% of the combustor air flow into the primary zone through the radial swirler. Radial gas composition measurements at various axial distances were made and these showed that the flame stability and NOx emissions were controlled by differences in local mixing at the base of the swirling shear layer downstream of the swirler outlet. For radial passage fuel injection it was found that a very high combustion efficiency was obtained for both propane and liquid fuels at 400K and 600K inlet temperatures. The flame stability, although worse than for central fuel injection was considerably better than for a premixed system. The NOx emissions at one bar pressure and 600K inlet temperature, compatible with a high combustion efficiency, for propane and kerosene were 3 and 6 ppm at 15% oxygen. For Gas Oil the NOx emissions were higher, but were still very low at 12ppm. Assuming a square root dependence of NOx on pressure these results indicate that NOx emissions of 48ppm for Gas Oil and less than 12ppm for gaseous fuels could be achieved at 16 bar pressure, which is typical of recent industrial gas turbines. High air flow radial swirlers with passage fuel injection have the potential for a dry solution to the NOx emissions regulations.


1992 ◽  
Vol 114 (3) ◽  
pp. 515-521 ◽  
Author(s):  
B. D. Hsu ◽  
G. L. Confer ◽  
Z. J. Shen

In the GE 7FDL single-cylinder research diesel engine, coal-water slurry (CWS) fuel combustion optimization studies were conducted using electronically controlled CWS and pilot accumulator injectors. The most important performance parameters of peak firing pressure, combustion efficiency (coal burnout), and specific fuel comsumption were evaluated in relationship to CWS and pilot injection timing, CWS injector hole size, shape, and number, CWS fuel injection spray angles and injection pressure. Heat release diagrams, as well as exhaust samples (gaseous and particulate), were analyzed for each case. Interesting effects of fuel spray impingement and CWS fuel “Delayed Ignition” were observed. With the engine operating at 2.0 MPa IMEP and 1050 rpm, it was able to obtain over 99.5 percent combustion efficiency while holding the cylinder firing pressure below 17 MPa and thermal efficiency equivalent to diesel fuel operation.


2001 ◽  
Vol 7 (6) ◽  
pp. 375-385 ◽  
Author(s):  
R. C. Hendricks ◽  
D. T. Shouse ◽  
W. M. Roquemore ◽  
D. L. Burrus ◽  
B. S. Duncan ◽  
...  

The Trapped Vortex Combustor (TVC) potentially offers numerous operational advantages over current production gas turbine engine combustors. These include lower weight, lower pollutant emissions, effective flame stabilization, high combustion efficiency, excellent high altitude relight capability, and operation in the lean burn or RQL modes of combustion. The present work describes the operational principles of the TVC, and extends diffuser velocities toward choked flow and provides system performance data. Performance data include EINOx results for various fuel-air ratios and combustor residence times, combustion efficiency as a function of combustor residence time, and combustor lean blow-out (LBO) performance. Computational fluid dynamics (CFD) simulations using liquid spray droplet evaporation and combustion modeling are performed and related to flow structures observed in photographs of the combustor. The CFD results are used to understand the aerodynamics and combustion features under different fueling conditions. Performance data acquired to date are favorable compared to conventional gas turbine combustors. Further testing over a wider range of fuel-air ratios, fuel flow splits, and pressure ratios is in progress to explore the TVC performance. In addition, alternate configurations for the upstream pressure feed, including bi-pass diffusion schemes, as well as variations on the fuel injection patterns, are currently in test and evaluation phases.


Author(s):  
Usman Asad ◽  
Ming Zheng

High hydrocarbon levels in the exhaust, increased cycle-to-cycle variation and reduced energy-efficiency are typical problems associated with diesel LTC operation. To overcome these challenges, three different fuel injection strategies (late single-injection, early multiple-injections and split-injections) have been investigated on a modified single cylinder common-rail diesel engine. The effects of EGR, boost and injection pressure on the emissions and combustion efficiency have been analyzed. The effect of heavy EGR has been quantified in terms of a trade-off between the combustion phasing and the combustion efficiency. To minimize fuel condensation and wall-wetting with early injections, a criterion for selecting the earliest timing for injection during the compression stroke has also been evaluated. This research is concluded with the formulation of a load management strategy to enable energy-efficient diesel LTC up to 10 bar IMEP.


2021 ◽  
Author(s):  
A. Yu Vasilyev ◽  
O. G. Chelebyan ◽  
A. I. Maiorova ◽  
A. N. Tarasenko ◽  
D. S. Tarasov ◽  
...  

Abstract The work is devoted to the design of a spraying device for the combustion chamber GTE-65.1 on liquid fuel. The paper presents the following results: 1) The 3D calculations of the air channels characteristics for two burners types — pilot and main — were carried out. Data were obtained on the flow and pressure fields inside and at the burners outlet, and also the volumes of the reverse flow zones. 2) The main and pilot nozzles have been designed for the two spraying devices types. The values of droplet dispersity and spray angle were obtained, depending on the fuel injection pressure. 3) Based on the calculations carried out, the models of two spraying liquid fuel devices were designed and manufactured, the design of which is based on the design of the single-fuel combustion chamber (CC) on natural gas burners for GTE-65.1. At the next stage of the work, it is planned to carry out experimental studies of the two devices models aimed at obtaining an aerosol mixture with the desired properties to ensure uninterrupted operation of the GTE-65.1 on liquid fuel. Some preliminary experimental data are presented in this paper.


Author(s):  
Christopher J. Mordaunt ◽  
Seong-Young Lee ◽  
Vickey B. Kalaskar ◽  
Amy Mensch ◽  
Robert J. Santoro ◽  
...  

Future gas turbine technology may require that liquid fuels play an additional role as a coolant over a wide range of combustion-chamber operating conditions. Additionally, in order to satisfy greater efficiency and performance goals, gas turbine operating temperatures and pressures are steadily increasing. Given the desire to reduce dependence on foreign fuels and that current hydrocarbon fuels, such as JP-8, are prone to thermal or catalytic decomposition at such elevated conditions, there is great interest in utilizing alternatively-derived liquid fuels. The successful development of a versatile, multiple-use fuel must achieve the desired operational characteristics of high combustion efficiency, excellent combustion stability, acceptable pollutant emission levels, and compatibility with current engine seals. Combustion instability represents a critical area of concern for future gas turbine engines that may burn alternative fuels. Combustion instability is characterized by large, unsteady combustion-chamber pressure oscillations which occur at the characteristic frequencies associated with the acoustic modes of the combustor. The occurrence of combustion-driven instabilities is closely tied to the details of the injection and fuel-air mixing processes, the heat release characteristics, and the degree to which heat release rate couples with the acoustics of the combustor. Additionally, the efficiency and emissions characteristics are also largely determined by the fuel injection, atomization, and mixing processes associated with combustion. As fuel properties and composition vary, effects on combustion efficiency and emissions, especially the formation of nitrogen oxides (NOx) and soot, can be expected. Therefore, changes in these processes attributed to differing fuel properties can have a dramatic affect on the combustion characteristics and require careful consideration through a well-coordinated combustion research program. The current study investigates whether a coal-based aviation fuel, JP-900, which has the required thermal stability attributes, also satisfies the engine combustion requirements. Additionally, a Fischer-Tropsch fuel and a volumetric 50/50 blend of JP-8 and the Fischer-Tropsch fuel are studied. Previous studies of coal-based fuels have shown that soot production can be a significant problem due to the higher aromatic content than found in conventional fuels. However, improvements in the fuel refinement processes have helped reduce this problem. Experiments included in this current research effort involve studying the combustion instability patterns, the pollutant emission levels, and sooting propensity of coal-based and Fischer-Tropsch fuels as compared to JP-8. The experimental setup consists of an optically-accessible model gas turbine dump combustor, with provisions for laser extinction measurements, which utilizes a Delavan hollow-cone pressure atomizer for fuel injection.


Author(s):  
John Crane ◽  
Yedidia Neumeier ◽  
Jeff Jagoda ◽  
Jerry Seitzman ◽  
Ben T. Zinn

This paper describes an investigation of the performance of the recently developed ultra low emissions, Stagnation-Point Reverse-Flow (SPRF) Combustor when burning liquid fuels (Jet-A and heptane). This study has been undertaken because of the need to burn liquid fuels with low emissions in gas turbines that are used, for example, in aircraft engines, land-based power generation, and marine applications. In contrast with state of the art combustors, in which the reactants and products enter and leave the combustor through opposite ends of the combustor, the reactants and products enter and leave the SPRF combustor through the same plane opposite a closed end. The design of the SPRF combustor allows mixing of reactants with hot combustion products and radicals within the combustor, prior to combustion. Thus, no external premixing of fuel and air is required. Additionally, since the air and fuel enter opposite the closed end of the combustor, they must stagnate near the closed end, thus establishing a region of low velocity just upstream of the closed end that helps stabilize the combustion process. This apparently produces a low temperature, stable, distributed reaction zone. Previous studies with the SPRF combustor investigated its performance while burning natural gas. This paper presents the results of SPRF combustor studies using liquid fuels, both heptane and Jet-A. The performance of the combustor was investigated using an airblast fuel injector, which is suitable for the low fuel flow rates used in laboratory experiments. To reduce pressure losses across the injector, a diffuser was incorporated into the airblast injector. It was found that stable combustor operation was achieved burning Jet-A with emissions of less than 1 ppm NOx and 5 ppm CO, pressure losses less than 5 percent, and a power density on the order of 10 MW/m3 in atmospheric pressure. This power density would linearly scale to 300 MW/m3 in a combustor at a pressure of 30 atmospheres.


Author(s):  
Woo Seok Seol ◽  
Yeoung Min Han ◽  
Dae Sung Lee

Lean fuel modules are sometimes employed to reduce NOx emissions in aero-engine combustors. With a lean fuel module whose AFR is larger than the stoichiometric AFR, the bulk AFR remains larger than the stoichiometric AFR throughout the combustor, and hence the peak NOx producing regime can be avoided. In addition, by introducing a large amount of air at the fuel injection point and increasing the mixing rate, the existing time of local stoichiometric pockets can be reduced. In the present study, flow and spray characteristics of a 21AFR lean fuel module, which consists of a pressure jet fuel injector and radial air swirlers, are measured by an adaptive Phase/Doppler technique. Gas phase velocity field, and distributions of droplet size, number density, and liquid phase volume flux are presented for co-swirl and counter-swirl lean modules. The present study reveals that a strong reverse flow zone is formed by the lean fuel module with radial swirlers. The shape of the reverse flow zone and the reverse flow velocity depend on the swirl direction significantly. The lean fuel module with radial swirlers provides effective atomization, and the SMD distribution near the module exit is quite uniform. The swirl direction has significant effects on the spray characteristics, too.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 794
Author(s):  
Heena Panchasara ◽  
Nanjappa Ashwath

Bio-oils produced by biomass pyrolysis are substantially different from those produced by petroleum-based fuels and biodiesel. However, they could serve as valuable alternatives to fossil fuels to achieve carbon neutral future. The literature review indicates that the current use of bio-oils in gas turbines and compression-ignition (diesel) engines is limited due to problems associated with atomisation and combustion. The review also identifies the progress made in pyrolysis bio-oil spray combustion via standardisation of fuel properties, optimising atomisation and combustion, and understanding long-term reliability of engines. The key strategies that need to be adapted to efficiently atomise and combust bio-oils include, efficient atomisation techniques such as twin fluid atomisation, pressure atomisation and more advanced and novel effervescent atomisation, fuel and air preheating, flame stabilization using swrilers, and filtering the solid content from the pyrolysis oils. Once these strategies are implemented, bio-oils can enhance combustion efficiency and reduce greenhouse gas (GHG) emission. Overall, this study clearly indicates that pyrolysis bio-oils have the ability to substitute fossil fuels, but fuel injection problems need to be tackled in order to insure proper atomisation and combustion of the fuel.


Sign in / Sign up

Export Citation Format

Share Document