Littérature scientifique sur le sujet « Prefilming airblast injector »
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Articles de revues sur le sujet "Prefilming airblast injector"
1
Hoffmann, Sven, Simon Holz, Rainer Koch et Hans-Jörg Bauer. « Euler–Lagrangian simulation of the fuel spray of a planar prefilming airblast atomizer ». CEAS Aeronautical Journal 12, no 2 (21 février 2021) : 245–59. http://dx.doi.org/10.1007/s13272-021-00493-y.
Texte intégralRésumé :
AbstractThe pollutant emissions of aircraft engines are strongly affected by the fuel injection into the combustion chamber. Hence, the precise description of the fuel spray is required in order to predict these emissions more reliably. The characteristics of a spray is determined during the atomization process, especially during primary breakup in the vicinity of the atomizer nozzle. Currently, Euler-Lagrangian approaches are used to predict the droplet trajectories in combustor simulations along with reaction and pollutant formation models. To be able to reliably predict pollutant emissions in the future, well-defined starting conditions of the liquid fuel droplets close to the atomizer nozzle are necessary. In the present work, Euler-Lagrangian simulations of a generic airblast atomizer are presented. The starting conditions of the droplets are varied in the simulations by means of a primary breakup model, which takes into account the local gas velocity when predicting the droplet diameter. The objective of this work is to determine the optimal parameters of the probability density functions for the starting position and the starting velocity of the droplets. Spray properties observed in the simulations are used to qualitatively evaluate the major effects of the distribution parameters on the spray and the suitability of the primary breakup model being applied. Hence, the spatial distribution of an experimental spray can be reproduced using a statistical model for the droplet starting conditions.
2
Meier, U., L. Lange, J. Heinze, C. Hassa, S. Sadig et D. Luff. « Optical Methods for Studies of Self-Excited Oscillations and the Effect of Dampers in a High Pressure Single Sector Combustor ». Journal of Engineering for Gas Turbines and Power 137, no 7 (1 juillet 2015). http://dx.doi.org/10.1115/1.4029355.
Texte intégralRésumé :
Self-excited periodic instabilities in a staged lean burn injector could be forced by operating the combustor at off-design conditions. These pressure oscillations were studied in a high pressure single sector combustor with optical access. Two damper configurations were installed and tested with respect to their damping efficiency in relation to the configuration without dampers. For a variety of test conditions, derived from a part load case, time traces of pressure in the combustor were measured, and amplitudes were derived from their Fourier transformation. These measurements were performed for several combinations of the operating parameters, i.e., injector pressure drop, air/fuel ratio (AFR), pilot/main fuel split, and preheat temperature. These tests “ranked” the respective damper configurations and their individual efficiency with respect to the configuration without dampers. Although a general trend could be observed, the ranking was not strictly consistent for all operating conditions. For several test cases, preferably with pronounced self-excited pressure oscillations, phase-resolved planar optical measurement techniques were applied to investigate the change of spatial structures of fuel, reaction zones, and temperature distributions over a period of an oscillation. A pulsating motion was detected for both pilot and main flame, driven by a pulsating transport of the liquid fuel. This pulsation, in turn, is caused by a fluctuating air velocity, in connection with a prefilming airblast type atomizer. A phase shift between pilot and main injector heat release was observed, corresponding to a shift of fuel penetration. Local Rayleigh indices were calculated qualitatively, based on phase-resolved OH chemiluminescence used as marker for heat release, and corresponding pressure values. This identified regions, where a local amplification of pressure oscillations occurred. These regions were largely identical to the reaction regions of pilot and main injector, whereas the recirculation zone between the injector flows was found to exhibit a damping effect.
3
Puggelli, S., D. Bertini, L. Mazzei et A. Andreini. « Modeling Strategies for Large Eddy Simulation of Lean Burn Spray Flames ». Journal of Engineering for Gas Turbines and Power 140, no 5 (21 novembre 2017). http://dx.doi.org/10.1115/1.4038127.
Texte intégralRésumé :
Over the last years, aero-engines are progressively evolving toward design concepts that permit improvements in terms of engine safety, fuel economy, and pollutant emissions. With the aim of satisfying the strict NOx reduction targets imposed by ICAO-CAEP, lean burn technology is one of the most promising solutions even if it must face safety concerns and technical issues. Hence, a depth insight on lean burn combustion is required, and computational fluid dynamics can be a useful tool for this purpose. In this work, a comparison in large eddy simulation (LES) framework of two widely employed combustion approaches like the artificially thickened flame (ATF) and the flamelet generated manifold (FGM) is performed using ANSYS fluent v16.2. Two literature test cases with increasing complexity in terms of geometry, flow field, and operating conditions are considered. First, capabilities of FGM are evaluated on a single swirler burner operating at ambient pressure with a standard pressure atomizer for spray injection. Then, a second test case, operated at 4 bar, is simulated. Here, kerosene fuel is burned after an injection through a prefilming airblast atomizer within a corotating double swirler. Obtained comparisons with experimental results show different capabilities of ATF and FGM in modeling the partially premixed behavior of the flame and provide an overview of the main strengths and limitations of the modeling strategies under investigation.
Thèses sur le sujet "Prefilming airblast injector"
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GIUSTI, ANDREA. « Development of numerical tools for the analysis of advanced airblast injection systems for lean burn aero-engine combustors ». Doctoral thesis, 2014. http://hdl.handle.net/2158/867029.
Texte intégralRésumé :
The liquid fuel preparation has a strong impact on the combustion process and consequently on pollutant emissions.
However, currently there are no validated and computational affordable methods available to predict the spray breakup process and to reliably compute the spray distribution generated after primary breakup. This research activity, carried out within the framework of the European project FIRST (Fuel Injector Research for Sustainable Transport), is aimed at developing reliable tools to be used in the industrial design process able to describe the processes involved in liquid fuel preparation in advanced injection systems based on prefilming airblast concept.
A multi-coupled solver for prefilming airblast injectors which includes liquid film evolution and primary breakup was developed in the framework of OpenFOAM. The solver is aimed at improving the description of the complex physical phenomena characterizing liquid fuel preparation and spray evolution in advanced airblast injection systems within the context of typical RANS (U-RANS) industrial calculations. In this kind of injectors, gas-phase, droplet and liquid film interact with each other, thus, in order to properly predict spray evolution and fuel distribution inside the combustor, proper tools able to catch the most important interactions among the different phases are necessary. A steady-state Eulerian-Lagrangian approach was introduced in the code together with up-to-date evaporation and secondary breakup models. Particular attention was devoted to the liquid film primary breakup and to the interactions between gas-phase and liquid film. A new primary breakup model for liquid films, basically a phenomenological model which exploits liquid film and gas-phase solutions for the computation of spray characteristics after breakup, was developed and implemented in the code. Different formulations for the computation of droplet diameter after breakup were evaluated and revised on the basis of recent experimental findings. The multi-coupled solver was validated against literature test cases with detailed experimental measurements and eventually applied to the simulation of an advanced prefilming airblast injector based on the PERM concept in a tubular combustor configuration.
The proposed approach allows us to better describe the fuel evolution in the injector region leading to a more comprehensive and physically consistent description of the phenomena regulating liquid fuel preparation compared to standard approaches which neglect the presence of liquid film and its interaction with both droplets and gas-phase.
Actes de conférences sur le sujet "Prefilming airblast injector"
1
Li, Jianing, Mahmoud Hamza, Arul Kumaran, Umesh Bhayaraju et San-Mou Jeng. « Study of Development of a Novel Dual Phase Airblast Injector for Gas Turbine Combustor ». Dans ASME Turbo Expo 2016 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56340.
Texte intégralRésumé :
A novel airblast injector is designed for gas turbine combustors. Unlike standard pressure swirl and prefilming/non-prefilming air blast atomizers, the novel injector is designed to improve the fuel injection delivery to the injector and improve atomization of the fuel by using a porous stainless steel tube. There are three swirling air streams in the injector. The liquid fuel is injected through the porous tube, with 7 micron porosity, between the swirling air streams, viz. an inner swirling air through the tube and the other two swirling air streams merging downstream of the tube. The swirl vane angles and the air split ratio are selected to increase the amount of air through the injector and facilitate the atomization process. The liquid fuel is injected through the outer surface of the porous tube, due to the permeability of the tube, produces a thin liquid sheet on the inner surface of the tube. The atomization occurs by surface stripping of the liquid sheet. The advantage of such an injector is that it produces a liquid sheet with uniform thickness around the circumference of the tube under all liquid loading. The porous tube also increases the surface area of contact between the fuel and air and produces a fine spray at engine idle conditions. An experimental approach is adopted in the present study to characterize the spray and aerodynamics of the injector for Jet-A and Gas-To-Liquid (GTL) fuels at atmospheric conditions. The effect of flare height on the Sauter Mean Diameter (SMD) is also studied. Spray characterization, droplet size and volume flux are investigated with PDI measurements. The effect of pressure drop and fuel properties on SMD distribution is analyzed. Velocity profiles at downstream of the injector are obtained from LDV measurements, and the velocity profile at the exit of the injector is also analyzed. A central toroidal recirculation zone (CTRZ) is observed at the exit of the injector. The effect of different configurations of the injector on spray characteristics is studied. A correlation for SMD is obtained.
2
O’Shaughnessy, Paul J., Richard J. Bideau et Qing-ping Zheng. « Injector Geometry Effect on Plain Jet Airblast Atomisation ». Dans ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-445.
Texte intégralRésumé :
Airblast atomisation drop size is a function of the liquid and gas flow conditions. It is also subject to the atomisation geometry, or more specifically the jet breakup mechanism. Plain jet atomisation featuring coaxial air and fuel flows has been investigated to assess the injector geometry effect on the spray characteristics. Results from various flow conditions and atomiser configurations suggest that a prompt atomisation correlation that was evaluated for prefilming injectors can be applied to plain jet airblast atomisation, in a slightly modified form. Changes in the velocity term are necessary to fit the measured data. A scaling factor has been established to compensate for the velocity term change. This factor may also imply the underlying difference between flat sheet and round jet atomisation. The liquid atomisation mode is dependent not only on the manner of geometrical air-liquid contact but also on flow conditions. In this study, the combined air-fuel velocity ratio VR and Weber number (WeVR) is found to be a criteria that determines the air flow pattern influence on atomisation. Data from this experiment show that a small change in the axial distance between the liquid jet and air orifice entrance results in marked difference in spray drop mean size under low air momentum flow conditions.
3
Gosselin, Valentin, Bernard Ferret et Rudy Bazile. « Coupled study of film and spray on a basic annular prefiming airblast atomizer ». Dans ILASS2017 - 28th European Conference on Liquid Atomization and Spray Systems. Valencia : Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/ilass2017.2017.4626.
Texte intégralRésumé :
One way to increase efficiency and reduce pollution in transport and energetic domain is designing fuel injectorswith better atomization. In this work, experiments were performed on a prefilming airblast atomizer often used in gas turbine engines. For this purpose, a new injector was designed to visualize the prefilming zone and the primary atomization together. The flow configuration corresponds to an annular liquid film sheared by inner high velocity airflows. High speed Shadowgraphy was used to observe film and spray, liquid film frequency, wave velocity and wave deformation, primary breakup regime. Finally, a link between liquid film and the primaryatomization are shown first qualitatively and after quantitatively.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4626
4
Wetherell, Jack R. J., Andrew Garmory et Maciej Skarysz. « Coupled Level Set Volume of Fluid Simulations of Prefilming Airblast Atomization With Adaptive Meshing ». Dans ASME Turbo Expo 2020 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14213.
Texte intégralRésumé :
Abstract The fuel atomisation process and the resultant spray affects nearly all aspects of combustion system performance, and must be well understood to enable the design of future combustion systems. The design of a fuel injector makes both numerical and experimental testing difficult, so simplified test pieces are often used, however, this does not accurately capture atomisation mechanisms and fuel distributions. This paper presents a computational method combining a Coupled Level Set Volume of Fluid model with Adaptive Mesh Refinement. A simple prefilmer has been used to validate the method. Comparisons of the flow field and ligament length distributions show good agreement with published DNS data. The use of AMR allows a lower total cell count, and so a reduction in computational cost of over 60% compared to previously reported results for the same case has been achieved. Further work will look to apply this method to more realistic injector geometry.
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Crayford, Andrew P., Franck Lacan, Jon Runyon, Philip J. Bowen, Shrinivas Balwadkar, Joseph Harper et Daniel G. Pugh. « Manufacture, Characterization and Stability Limits of an AM Prefilming Air-Blast Atomizer ». Dans ASME Turbo Expo 2019 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-91624.
Texte intégralRésumé :
Abstract With the recent advancement of metallic additive manufacturing (AM), it is perceived that future gas turbines will be manufactured with significantly fewer parts, leading to both financial and safety improvements achieved from reductions in weight, assembly processes and failure modes associated with welded parts. In addition the design and manufacture of highly intricate parts such as fuel atomizers become free from the constraints of tooling, facilitating more complex internal flow geometries to be conceived which afford improved atomization, flame stability and hence combustion efficiency. However, it is noted that increased dimensional tolerances and surface roughness resulting from this manufacturing technique can detrimentally impact internal air and fuel flow paths and hence warrant further investigation. In this study a small-scale (200kW) pre-filming airblast atomizer, based on the Parker Hannifin commercial concept, and typical of injectors utilized in RQL aviation combustors, was manufactured by Cardiff School of Engineering’s High Value Manufacturing Laboratories. Direct metal laser sintering, was utilized to produce a fully operational single component part, manufactured in 316-grade stainless steel using a Renishaw AM250 system, providing a part with measured surface roughness (Ra) values of 12–26 μm in agreement with expected values reported in the literature. Operation of the injector as a single fluid atomizer demonstrated that the fuel channel and integrated swirlers were sufficiently accurate and concentric to result in a uniform spray pattern, displaying global liquid sheet structures which were in agreement with those previously reported. However, the effective area of the atomizer’s air-flow path, when evaluated using differential pressure measurements, was shown to be smaller than predicted, resulting in an increased pressure drop. Laser diffraction droplet sizing was utilized to evaluate the global SMD of the prefilming airblast water spray at atmospheric conditions, across a range of air to liquid ratios. SMD’s between 4.2–115μm were measured at corresponding air-flow rates of 3–25 g/s, with droplet sizes observed to decrease exponentially at higher air-flow rates. This data is again in excellent agreement with SMD correlations previously proposed. Flame stability experiments conducted at ambient pressure and elevated air temperature, demonstrated the stability of a conventional (JET A-1) fuel flame across a range of air and fuel flow rates, representative of pressure drops and AFRs in commercial operation. Further post-processing of the internal flow path walls and swirl vanes to reduce surface roughness is anticipated to result in a lower pressure drop across the air-path geometry, highlighting the potential for further improvements in AM injector performance.
6
Li, Jianing, Umesh Bhayaraju et San-Mou Jeng. « Characterization of a Novel Porous Injector for Multi-Lean Direct Injection (M-LDI) Combustor ». Dans ASME Turbo Expo 2017 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63981.
Texte intégralRésumé :
A generic novel injector was designed for multi-Lean Direct Injection (M-LDI) combustors. One of the drawbacks of the conventional pressure swirl and prefilming type airblast atomizers is the difficulty of obtaining a uniform symmetric spray under all operating conditions. Micro-channels are needed inside the injector for uniformly distributing the fuel. The problem of non-uniformity is magnified in smaller sized injectors. The non-uniform liquid sheet causes local fuel rich/lean zones leading to higher NOx emissions. To overcome these problems, a novel fuel injector was designed to improve the fuel delivery to the injector by using a porous stainless steel material with 30 μm porosity. The porous tube also acts as a prefilming surface. Liquid and gaseous fuels can be injected through the injector. In the present study, gaseous fuel was injected to investigate injector fuel-air mixing performance. The gaseous fuel was injected through a porous tube between two radial-radial swirling air streams to facilitate fuel-air mixing. The advantage of this injector is that it increases the contact surface area between the fuel-air at the fuel injection point. The increased contact area enhances fuel-air mixing. Fuel-air mixing and combustion studies were carried out for both gaseous and liquid fuel. Flame visualization, and emissions measurements were carried out inside the exit of the combustor. The measurements were carried out at atmospheric conditions under fuel lean conditions. Natural gas was used as a fuel in these experiments. Fuel-air mixing studies were carried out at different equivalence ratios with and without confinement. The mass fraction distributions were measured at different downstream locations from the injector exit. Flame characterization was carried out by chemiluminescence at different equivalence ratios and inlet air temperatures. Symmetry of the flame, flame length and heat release distribution were analyzed from the flame images. The effects of inlet air temperature and combustion flame temperature on emissions was studied. Emissions were corrected to 15% O2 concentration. NOx emissions increase with inlet air temperature and flame temperature. Effect of flame temperature on NOx concentration is more significant than effect of inlet air temperature. Fuel-air mixing profile was used to obtain mass fraction Probability Density Function (pdf). The pdfs were used for simulations in Chemkin Pro. The measured emissions concentrations at the exit of the injector was compared with simulations. In Chemkin model, a network model with several PSRs (perfectly stirred reactor) were utilized, followed by a mixer and a PFR (plug flow reactor). The comparison between the simulations and the experimental results was investigated.
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Strasser, Wayne. « Can Naturally Pulsating Prefilming Slurry Atomization Be Enhanced by Artificial External Modulation ? » Dans ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-4882.
Texte intégralRésumé :
Abstract Under certain conditions in preferred three-stream geometries, a non-Newtonian airblast atomization flowfield violently pulses (axially and radially) by self-generating and self-sustaining interfacial instability mechanisms. The pulsing is severe enough to send acoustic waves throughout feed piping networks. The most recent work on this system instructed that exothermic chemical reactions enhance this moderate Mach number atomization. Explored herein is the potential to further enhance reaction-assisted disintegration by independently superimposing both sinusoidal and randomized mass flow fluctuations of +/− 50% of the mean onto otherwise constant gas feed streams. Two nozzle geometries (low versus high prefilming distance) and multiple superimposed feed frequencies (ranging from below to above the naturally dominant tone) are considered for each gas stream, making twenty-one total long-running unsteady PLIC-VOF CFD models. Droplet size, plus nine other temporal measures, were considered for assessing atomizer performance in our energy production process. Results indicate that superimposed frequencies have potential to enhance chaotic atomization in a statistically significant manner. Depending on the geometry, the largest effect was about a 10% reduction in droplet size; however, some combinations experienced a droplet size increase. Only marginal differences were seen in the nine other measures, such as injector face heat exposure. In addition to the immediate industrial benefit from modulation, dramatic changes in acoustics were produced by imposed feed perturbations at frequencies lower than the natural tone. A detailed study of start-up flow reveals new mechanisms which explain performance differences.
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Meier, U., L. Lange, J. Heinze, C. Hassa, S. Sadig et D. Luff. « Optical Methods for Studies of Self-Excited Oscillations and the Effect of Dampers in a High Pressure Single Sector Combustor ». Dans ASME Turbo Expo 2014 : Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25873.
Texte intégralRésumé :
Self-excited periodic instabilities in a staged lean burn injector could be forced by operating the combustor at off-design conditions. These pressure oscillations were studied in a high pressure single sector combustor with optical access. Two damper configurations were installed and tested with respect to their damping efficiency in relation to the configuration without dampers. For a variety of test conditions, derived from a part load case, time traces of pressure in the combustor were measured, and amplitudes were derived from their Fourier transformation. These measurements were performed for several combinations of the operating parameters, i.e., injector pressure drop, air/fuel ratio, pilot/main fuel split and preheat temperature. These tests “ranked” the respective damper configurations and their individual efficiency with respect to the configuration without dampers. Although a general trend could be observed, the ranking was not strictly consistent for all operating conditions. For several test cases, preferably with pronounced self-excited pressure oscillations, phase-resolved planar optical measurement techniques were applied to investigate the change of spatial structures of fuel, reaction zones and temperature distributions over a period of an oscillation. A pulsating motion was detected for both pilot and main flame, driven by a pulsating transport of the liquid fuel. This pulsation, in turn, is caused by a fluctuating air velocity, in connection with a prefilming airblast type atomizer. A phase shift between pilot and main injector heat release was observed, corresponding to a shift of fuel penetration. Local Rayleigh indices were calculated qualitatively, based on phase-resolved OH chemiluminescence used as marker for heat release, and corresponding pressure values. This identified regions, where a local amplification of pressure oscillations occurred. These regions were largely identical to the reaction regions of pilot and main injector, whereas the recirculation zone between the injector flows was found to exhibit a damping effect.
9
Chin, Ju S., Nader K. Rizk et Mohan K. Razdan. « Study on High Liquid Pressure Internal Mixing Prefilming Airblast Atomization ». Dans ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-442.
Texte intégralRésumé :
The objective of the present investigation is to provide better understanding of the hybrid atomization process in an effort to support the development of fuel injectors for future high performance / low emissions gas turbine combustors. A specially designed atomizer that incorporated two swirling air streams, and a prefilming device located upstream of the atomizer exit section was tested under a combined hybrid airblast and high liquid pressure mode. The experiments focused on evaluating the effects of several operating parameters, in particular the air / liquid ratio, on the atomization quality. The results demonstrated that, to accurately determine the role of the air / liquid ratio in the atomization process, the effects of liquid injection velocity and the relative air–liquid velocity need to be separated from that of the air / liquid ratio. Two approaches were used in the present investigation to deduce the actual effect of the air / liquid ratio: first, by reducing the air swirler flow areas, and second, by increasing the number of liquid injection holes. Both approaches enabled changing the air / liquid ratio without changing the air or liquid velocities. The atomization results indicate that changes in swirler flow area produce a stronger effect of the air / liquid ratio than that when liquid hole number was changed. For fixed air / liquid ratio, better atomization quality was achieved when both levels of air flow and liquid flow were high compared to when both flow rates were low. Also, the atomizer demonstrated a continuous improvement in atomization quality under very high air pressure drop, indicating a better utilization of the air kinetic energy over conventional airblast atomizers. The other important observation was that the dependency of the atomization process on air velocity was not constant, but rather changed with liquid pressure, air flow rate, and air pressure drop.
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Gong, Jing, Yuzhen Lin, Quanhong Xu et Gaoen Liu. « Investigation of Combustion Performance of a Hybrid Airblast Atomizer Under Simulated Low Power Conditions ». Dans ASME Turbo Expo 2005 : Power for Land, Sea, and Air. ASMEDC, 2005. http://dx.doi.org/10.1115/gt2005-68219.
Texte intégralRésumé :
An aero gas turbine combustor has to meet requirements for both high and low power condition operation. Within the requirements for low power conditions, lean-blow-out (LBO) and combustion efficiency are the basic ones. A pure prefilming air blast atomizer may have difficulty meeting combustion requirements under low power conditions, such as, idle LBO, idle combustion efficiency, etc. Use of a hybrid airblast atomizer may offer a solution for such problems. A hybrid airblast atomizer is a single fuel injection unit that has both pilot and main fuel circuits. A simplex nozzle is often used for pilot fuel circuit and an airblast atomizer of the swirl cup type may be used for the main fuel circuit. For the main fuel circuit, fuel is injected from a number of plain jet holes. The fuel jets are injected towards a venturi, with the help of swirling air from another air swirler, and the main fuel is airblasted and well mixed with both swirler airflows. For low power conditions, the pilot fuel nozzle (simplex nozzle) works alone. Not all of the swirler air will mix with pilot nozzle fuel spray. With appropriate pilot nozzle pressure drop and with some airblast function, the pilot fuel is well atomized and does not fully mix with the swirler air nor with primary hole air. Thus, the low power condition combustion efficiency is improved. The investigation reported in the present paper has concentrated on hybrid atomizer combustion performance under simulated low power conditions, when only the pilot nozzle is operating. The study consists of the following parts: • Pilot nozzle drop size measurement; • Numerical simulation of combustor flow field; • Atmospheric ignition test; • Simulated idle condition LBO test; • Low power condition combustion efficiency test. Results are reported, and future work is defined.