Multi point i injection i system development at Snecma Presenter: Sébastien Bourgois (SN)
Outline Overview of Multipoint Injection System development at SNECMA Tools used for conception An example: LEMCOTEC Objectives of the LEMCOTEC project Technology description of the Multiple Staged Fuel Injection (MSFI) Combustor performances Planned test campaigns Conclusions and prospects
Injection d hydrogène Technologie multipoint avec injection d hydrogène Overview of Multipoint Injection System development at SNECMA Project Acronym Name Dates Results ETNA < 2005 First Multipoint conception at Snecma 1 st Multipoint concept at Snecma LOPOCOTEP Low Pollutants combustor technology programme 2001 2006 Instabilities bl due to interactions between the pilot flame and the Multipoint abandoned concept TLC Towards Lean Combustion 2005 2010 CAEP6 60% demonstration for NOx Advanced experimental assessment Establishment of a NOx correlation TOSCA Technologies pour l opérabilité des Systèmes d injection sur chambre Aéronautique 2007 2012 First ignition with Multipoint at Snecma First Injection System compliant with CO/ UHC emission levels requirements First cokefaction studies TECC AE Technologie Enhancement for Clean Combustion in Aero Engines 2007 2012 4spark plug positions, sub atmospheric at ONERA, cokefaction studies IMPACT Intelliigent Design Methodologie for Low Pollutant Combustors for Aero Engines 2011 2015 First test of a Multipoint injector scaled for Silvercrest LEMCOTEC Low Emissions Core Engine Technologies 2011 2015 First Full Annular Multipoint Combustor
Tools used for conception Advanced Numerical Simulations: RANS (N3Snatur) : Mean flow structures (recirculation zones, jet expansion...) Temperatures profiles at combustor outlet Permeability characterization of the injection system CO emission predictions (injection system optimization) LES (AVBP / YALES2) : Understanding and visualization of the combustion modes Interaction between pilot flame and multipoint Ignition and flame propagation between injectors Combustion instabilities Experimental tools: Velocity profiles in the combustor (non reactive) Kerosene droplet size distribution up to 14 bars Kerosene and OH visualization in the combustor up to 20 bars Temperature measurements in the combustor up to 20bars Sootmeasurements (Laser Induced Incandescence) Mapping of emissions and temperature at combustor outlet Synchronized measurements of evaporated kerosene, flame front, aerodynamics (EM2C)
LEMCOTEC LEMCOTEC: Low Emissions Core Engine Technologies Objectives : Conception of a full annular combustor in 2015 (TRL5) with multipoint technology «Low NOx / Low Smoke» Tests in representative operating conditions Assessment of LEMCOTEC combustor performances by means of RANS / LES computations and single sector / four sector and full annular tests Simulations intended dto estimate t combustor performances: temperature profiles, pollutant emissions, stability, ignition... FANN combustor tests in June 2015 Heat release with a pilot flame (center) and a highly turbulent multi points flame 5
Multiple Staged Fuel Injection (MSFI) description
Impact of fuel split on aerodynamic structures Aerodynamic structures t at 10% fuel split Strong inner recirculation zone Corner recirculation zone Rich central region Red: Heat Release isocontour Greyscale: Liquid fuel volume Fraction Blue: Stoichiometric line Redscale: Gaseous fuel mass fraction Aerodynamic structures at 20% fuel split The central region is richer and much larger Larger intersection between the pilot flame and the upper part of the main flame 10 % fuel-split CERFACS computation 20 % fuel-split
Impact of fuel split on local temperature and NOx formation LES performed with different fuel split (5%, 10% and 20%) to assess the effect on flame structure and Temperature profiles at combustor interface Non premixed zone is much larger in the 20% fuel split case Pilot region drives the NOx formation, this region is larger when fuel split is increased Increasing the fuel split is expected to increase the NOx formation (like Soot) Normalized Temperature CERFACS computation 10 % fuel-split 20 % fuel-split 8
Ignition in altitude relight conditions Using LES to study transient of ignition in altitude relight conditions Both Eulerian and Lagrangian description of the liquid phase during carburation Carburation and ignition of a single sector before full 360 study CERFACS computation
Combustion instabilities Evaluation the risk of instabilities of the LEMCOTEC combustor at full power conditions Studyof theeffecteffect of fuel split parameter Method: Use ATACAMAC (Analytical l Tool to Analyse and Control Azimuthal Modes in Annular Chamber) and AVSP to find the eigenfrequencies of the system Use these frequencies to force a multiphase flow LES on a single configuration to obtain the flame transfer function nction(ftf) Use these FTF as inputs in ATACAMAC and AVSP to predict the growth rate andstability of the configuration CERFACS computation
Test campaigns overview One sector test rig (ONERA M1) for the choice of the injector to be integrated on the full annular (FANN) combustor Four sector test rig (ONERA M1) at low pressure and sub atmospheric conditions: Stability and ignition capabilities, optimisation of fuel staging regarding combined requirement for operability and pollutant emissions reduction at part power conditions FANN Combustor High Pressure test campaign (DGA EP K8 bench): Pollutantemissions emissions, aerodynamicbehaviourandairflowsplit and air split, thermal behaviour on the combustor liners heat shields, temperature profiles at the combustor outlet, thermo acoustic behaviour FANN Combustor Altitude Relight test campaign (DGA EP A06 bench): Stability and ignition domains of the FANN combustor for several altitudes relight conditions in terms of air pressure and temperature at the combustor inlet, the effect of fuel ltemperature t and composition
One sector test rig at ONERA M1 test bench Three geometries of the injection system will be tested: Pollutant emissions for the ICAO certifications points Effects of fuel staging Tests are planned for September 2014 Experimental results will make possible the choice of the injector to be integrated on the annular combustor An arrangement of two definitions of injectors will equip the FANN combustor Injector Type 1 Injector Type 2
FANN combustor HP and AR test campaigns Two test phases of the full annular (FANN) combustor will be run in DGA EP test plan area in Saclay: High pressure tests (K8 test rig) Sub atmospheric pressure tests (A06 test rig) Objectives of the K8 test: Evaluation of the pressure losses and the flow distribution around the combustor Detection of the combustion instabilities Gas and smoke emission measurements Temperature profiles and wall temperatures measurements Objectives of the A06 test: Rlih Relight capability measurements, sub atmospheric relight envelope Plug immersion optimisation High pressure tests Sub atmospheric tests Test rig K8 A06 Pressure Max 22bar Min 0.3bar Temperature Max 873K Min 245K Mass flow Max 20kg/s Max 2kg/s Planned test phase May 2015 September 2015 A06 test rig K8 test rig
Conclusions LES tools are fully integrated into the design and the optimization process of innovative lean burn technologies. Valuable knowledge and deeper understanding is obtained regarding: The ignition i i and the propagation limits i of the flame The impact of fuel flow split on aerodynamic and temperature fields The robustness of the design against combustion instabilities Results provided d by dedicated di dtest trigs will make possible the assessment of numerical tools: One sector test rig (ONERA M1) for the choice of the injector to be integrated on the full annular (FANN) combustor Four sector test rig (ONERA M1) at low pressure and sub atmospheric conditions FANN High Pressure test campaign (DGA EP K8 bench) FANN Altitude Relight test campaign (DGA EP A06 bench) Multipoint technology for the future engine? Trade off with other performances and sensitivity to cycle
LES computations Model for NO formation Prospects Quantify the effect of fuel split and operating point on NO emission levels Combustion instabilities Analyse the effect of fuel split on the stability Ignition Simulation of flame propagation in a 360 configuration with large scale computation (~230 millions of cells) on thousands of procs. OGV / Combustor Interaction A non reactive LES simulation comprising both the outlet guide vanes and the combustor will be performed to study the coupling mechanisms between the disturbance coming from the detached flow of the OGV and the aerodynamic flow inside the combustor Test campaigns @ ONERA and DGA EP
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