Integrated Lean Low Emission Combustor Design Methodology

Transcription

1 Integrated Lean Low Emission Combustor Design Methodology Presenter: Ralf von der Bank (Rolls-Royce Deutschland)

2 Consortium University of of Loughborough Department Chemical Engineering Cambridge SNECMA Villaroche CNRS-LCD Poitiers ONERA Palaiseau Turbomeca Pau Imperial College London Rolls-Royce Derby CERFACS Toulouse DLR Köln AVIO Napoli Combustion Physics Universitet Lunds Università di di Firenze Rolls-Royce Deutschland Dahlewitz // Berlin University of of Czestochowa Universität Bundeswehr München Engler-Bunte Institut Universität Karlsruhe

3 Duration: 5 years Budget and Efforts Status YE 2009 Budget funding spent 7.64 M / 4.88 M 1 January December 2007 Completed on 31 December 2008 One task delayed to 31 December 2009 first prolongation used to invoke BOSS / HBK1 facility (larger Aeff) assumption was low risk, then cracks in the silencer found after safety concern the silencer s concrete structure was renovated 97 % 785 Person Months 66 Person Years 97 % Total Budget: 7,7 M EC Funding: 5,0 M Ratio: 64,6 % 93 deliverables + 47 milestones + 38 paper & conference publications

4 Global Project Targets Strengthening of competitiveness of European aero-engine manufacturers - reduce short & long term development costs by 20 and 50%, respectively - incorporate new technology faster into future products - project timescales to less than 2 years Improving the environmental impact with regards to emissions EC Target: - reducing of NOx emissions by 80% in the LTO cycle relative to CAEP/2 - achieving an NOx emission index of 5 g NOx per / kg fuel burnt ACARE A Vision for 2020 : - reduction of 50% CO 2 emissions (engine contribution 15-20%) - reducing NOx emissions by 80% with 60% combustion system contribution

5 Operability: Combustion Efficiency Cold Start, Ignition Altitude Relight Hail & Rain Slam Deceleration Weak Extinction Sprays: Spray Break-Up Spray Vaporisation Droplet Diameters Pre-Diffuser: Pressure Loss Air Feeding SFC Challenges Injectors: Air Blast / Multi-Point LPP LP(P) LDI Fuel System: Fuel Coking Schedule Staging Control Fuel Types Aromatics Combustor-Turbine Interaction: Degree of swirl at the back end of the combustor HPT NGV cooling and HPT efficiency LP(P) / LDI 50 to 80 % W30 Combustion Noise: Thermo-Acoustic Instabilities Combustion Driven Pressure Oscillations Mechanical Integrity Design: Weight Length Part Count Complexity Emissions NOx SOOT CO UHC Cooling: Life Prediction / Technology Surface to Volume Ratio Shape of the cooling holes

6 Technology Key Objectives Improvement of ultra-low NOx combustion systems - lean flame stability / weak extinction, flash-back & auto-ignition - low power conditions & transient engines operation Lean burn combustion - lower combustion temperature - reduced flame stability - may lead at very weak conditions - to severe increase of CO emissions and - unburnt hydro carbon emissions right before flame-out Deterioration when - slam deceleration during maneuvering in inclement weather conditions which leads to hail or rain (tropical storm) ingestion - with further reduced compressor outlet temperature and - reduced chemical reaction rates (moisture is almost inert)

7 Technology Trades SFC - CO 2 NOx Key Influencing Physical Factors P30/T30 SFC CO2 BPR SFC CO2 BPR Nacelle & Fan Drag P30 NOx T30 T40 NOx BPR AFR T40 NOx Source: M. Plohr, R.v.d.Bank, T.Schilling, DGLR , Munich, Germany Note: Fan and nacelle drag and weight variations were not considered. Higher P30/T30 and higher BPR improve thermal cycle and propulsive efficiency Reduction of fuel burn (SFC) and green house gas emissions (CO 2 ), but: Aggravated situation with respect to low NOx target / challenge

8 Project Structure WP3 WP3 Ignition Capability LUND Lunds Universitet Combustion WP4 WP4 RRD Stability & Extinction Rolls-Royce Deutschland Low NOx III WP2 WP2 - TM Knowledge Based Low Nox Combustor Turbomeca WP6 Technology Assessment Rolls-Royce United Kingdom LOPOCOTEP WP6 WP6 Loughborough University External Aerodynamics Air Distribution WP7 WP7 Combustor Cooling AVIO AVIO

9 Knowledge Based Low NOx Combustor Parametric combustor model (Z-Ring) Casing Z ring Cooling Deformed mesh Cowl Heat Shield Metering Panel Light or heavy KBE systems, which include all the combustor design rules. Light or heavy depending on the balance between fast implementation and adaptability to new system designs. Advanced optimisation techniques. In an industrial environment, a big effort is required to capture knowledge.

10 External Aerodynamics 35% up to 30% 35% 15% up to 70% 15% Lean Burn architecture: new challenge to External Aerodynamics design Optimise for minimum pressure loss and flow quality, optimised air distribution and OGV Developed software allows exploitation of 3D Pre-Diffuser exit height (with struts) LES of OGV/diffuser to develop constraint for 3D RANS more LES in the future

11 Combustor Cooling C d Cd manip h_ad Re2 = Re2 = Re1 = Re2 = Re1 = Re2 = Re2 = Re1 = Re2 = Re1 = Re2 = Re1 = Re2 = Re1 = Re2 = Re2 = Re2 = Re2 = Re h Re hole Understanding of air flow through effusion cooling holes improved and characterised Discharge coefficients for circular (cd = 0.7) and shaped cooling holes determined (0.85) Effusion cooling air flow simulated by LES and RANS CFD / very high spatial resolution Combustor wall temperatures predicted (convection and radiation / conjugate heat transfer)

12 Ignition Capability 00:00:00 00:05:43 00:05:44 00:05:49 00:05:52 00:05:54 00:05:56 00:05:58 00:06:01 Spark plug & laser pulse ignition High altitude relight (1-sector, 2 sector & sub-atm. FANN) capability > 30,000 ft demonstrated Fundamental spray break-up models implemented and validated Ignition, light-up, light across simulated in 3-sector CFD domain capability demonstrated Ignition process investigated with high-speed framing camera (spark plug & laser)

13 LN2B LP(P)5 Stability & Extinction NEW BOSS LPX1 LPX2 LN2B LPX1.MOD 700 m2 LPX1 LN2B LPX2 SARS Task LN2B S-FANN Task HBK3 Task 4.1 Task 5.1/ 5.2 EDS-SSC / BOSS Task 4.2 LP(P)4-P1 LPX1.MOD SARS Task 4.4 LPX1 B61 PERM M1-HPSS Task 4.3 LES-BOFFIN Task 4.5 / Task 3.1 ICL DESS Task 3.2

14 Synthetic Paraffinic Kerosine (one example GTL-SPK) GTL-SPK pet. Jet-A1 LIF / Mie scattering (kerosene) OH* chemiluminescence (heat release) doubling of ignition delay time to 12 sec. reduced soot deposit First time ever investigation of one GTL Generally less soot (no aromatics) NOx emissions increased (pilot PSA) Ignition delay time (distillation curve) Need for further research identified Results were not well understood

15 Assessment 1 Combustor Architectures BR715 RQL air blast burner optimised RQL potential NOx 60% CAEP/2 up to: NOx < 50% CAEP/2 LOPOCOTEP - LARGE A (CLEAN) NOx < 60% CAEP/2 E3E I ASC air blast NOx 47% CAEP/2 FP4 LowNOx III / ASC / LPP1 / LPP2 NOx < 57% CAEP/2 E3E II / ASC / SC1 NOx < 43% CAEP/2 FP5 LOPOCOTEP / LP(P)5 NOx < 40% CAEP/2 AM FP6 INTELLECT D.M. NOx < 26% CAEP/2 AM (LN2B) NOx = 6.6 g/kg (AM cruise)

16 Assessment 2 Continued Progress Medium size turbofan engines State of the art: Single Annular Combustors with rich burn (air blast) injection LowNOx III ( ) - proof of concept Double Annular Combustors / Axially Staged Combustors (rich/rich) First experience with lean burn injectors (mainly: LPP) LOPOCOTEP ( ) - proof of concept Double Annular Combustors / Axially Staged Combustors (rich/lean) First experience with piloted lean burn injectors (mainly: LP(P), LDI, Multi-Point) INTELLECT D.M. ( ) - proof of concept Single Annular Combustors with piloted lean burn injectors (mainly: LDI, PERM) Best results: 25.9 % CAEP/2 AM vs. 20% CAEP/2 (target EC FP6 work programme) Best results: 6.6 cruise vs. 5.0 EINOx,c (target EC FP6 work programme) First experience with operability (cruise operation, weak extinction, altitude relight, ignition (light-up,light-across, light-around), etc) On-going: Transition to higher TRL (NASA AST: NOx deterioration factor up to: ~1.5) Further optimisation and concept development

17 Assessment 3 emission performance of LDI modules Result of assessment of NOx performance on the ICAO LTO cycle (advanced medium size turbo-fan 129 kn - 100% T/O thrust, SLS) Injector type CAEP/2 limit [AM] CAEP/2 limit [C1] TRL LP(P)5 34.0% % 39.3% % (mlc - wc) 3 LPX1 33.3% 38.6% 3 LPX2 32.9% 38.2% 3 LN2B C % 29.5% 3 RQL (optimised) 62.8% 72.8% (from CYPRESS) 9 The LN2B fuel injector is almost achieving the EC target set (20% CAEP/2)

18 Conclusions all partners completed their technical/research work successfully first building bricks for light and heavy KBE systems were developed ignition capability (simulation and testing) was extended to lean burn systems advanced LDI systems were developed and tested for emissions and operability first time ever: Fischer-Tropsch GTL was investigated with advanced LDI module assessment showed that 80% NOx (CAEP/2) reduction can be achieved with LDI lean burn systems (medium size engines with 20 bar < P30 < 40 bar were targeted) further potential by UH-BPR and UH-OPR / further research required (CO2 and NOx) external combustor aerodynamics were optimised for 70% air flow though LDI module cooling technologies were driven to higher efficiency and higher cooling requirements

19 Group photo of the INTELLECT D.M. team at the Final Review Many thanks to the team! Ralf von der Bank, Integrated Lean Low Emission Combustor Design Methodology, Sixth European Aeronautics Days, Madrid, Spain, 30/3 March 1/ April C1