NEWAC Overall Specification, Assessment and Concept Optimization

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1 NEWAC Overall Specification, Assessment and Concept Optimization Andrew Rolt, Rolls-Royce plc. with contributions from: Konstantinos Kyprianidis, Cranfield University; Stefan Donnerhack and Wolfgang Sturm, MTU; Pascal Coat, Snecma; Salvatore Colantuoni, Avio; and Sebastian Bake, Rolls-Royce Deutschland Rolls-Royce plc and NEWAC 1

2 Outline of presentation NEWAC engine concepts SP1 organisation, partners and methods Techno-economic and environmental risk assessment (TERA2020) Study engines and technology assessments Lean-burn technologies and NOx emissions Conclusions 2010 Rolls-Royce plc and NEWAC 2

3 The four main NEWAC engine concepts assessed in SP1 Intercooled Flow controlled core Active core Intercooled and recuperated 2010 Rolls-Royce plc and NEWAC 3

4 SP1 Whole Engine Integration three work packages Work Package NEWAC study engines were specified and their performance and designs have been assessed, on an ongoing basis, in comparison with reference engines, to identify costs and benefits of NEWAC technologies - 30,000 and 70,000 lbf thrust engine designs were assessed against requirements set by Airbus for two aircraft types Short Range Long Range Work Package New combinations of NEWAC and other new technologies were proposed and assessed to see if they could better the original engine concepts Work Package The original NEWAC engines were modelled using TERA2020 software developed in the NEWAC, VITAL and DREAM programmes - TERA2020 extends the scope of the SP1 whole engine assessments and provides a tool for rapid initial evaluation of variant engine designs - Also used for sensitivity studies and optimization studies 2010 Rolls-Royce plc and NEWAC 4

5 SP1 Whole Engine Integration Partners in SP1 WP1.1 Specification & Assessment Airbus Rolls-Royce Deutschland Techspace Aero Turbomeca AVIO MTU Aero Engines Rolls-Royce plc Snecma Volvo Aero Cranfield University 2010 Rolls-Royce plc and NEWAC 5

6 SP1 Whole Engine Integration Partners in SP1 WP1.2 Integration & Optimisation WP1.1 Specification & Assessment Airbus Rolls-Royce Deutschland Techspace Aero Turbomeca AVIO MTU Aero Engines Rolls-Royce plc Snecma Volvo Aero Cranfield University 2010 Rolls-Royce plc and NEWAC 6

7 SP1 Whole Engine Integration Partners in SP1 WP1.2 Integration & Optimisation WP1.1 Specification & Assessment Airbus Rolls-Royce Deutschland Techspace Aero Turbomeca AVIO MTU Aero Engines Rolls-Royce plc Snecma Volvo Aero Cranfield University WP1.3 TERA2020 Chalmers University of Technology Technical University of Athens University of Stuttgart 2010 Rolls-Royce plc and NEWAC 7

8 Methods Established preliminary design methods were used by MTU, Rolls-Royce and Snecma to set specifications and technology targets for the seven turbofan engine models in WP1.1 and then for three additional models in WP1.2 Engine specification starts with the thrust requirements, a design concept and initial estimates of the performance available from major components and systems. The next step is to construct design and off-design performance models. Then major components are sized and the gas path annulus is defined. Iterative design studies and assessments are made to refine the performance model and to complete a preliminary mechanical layout for the engine. Finally nacelle lines are constructed and the overall powerplant weight, drag and unit cost can be assessed In WP1.3 the TERA2020 tool was used to model these engines and assess the economic and environmental impact of the new designs and technologies TERA2020 was also used to make sensitivity and optimization studies around the modelled engine configurations 2010 Rolls-Royce plc and NEWAC 8

Optimisation and design space exploration with TERA2020 Simplified representation of a design space explored with TERA2020 Block fuel benefits result mainly from improvements in: Note there is not

9 Optimisation and design space exploration with TERA2020 Simplified representation of a design space explored with TERA2020 Block fuel benefits result mainly from improvements in: Note there is not just one optimum design The optimum depends on the objective function and the applied constraints 1. The thermodynamic cycle (considering the engine weights and the aircraft mission). 2. Matching the engine to the aircraft (assessing the snowball thrust reduction effects by using a rubberized wing aircraft model) Rolls-Royce plc and NEWAC 9

10 Comparison of TERA2020 results for optimised engine/aircraft combinations with the corresponding initial (nominal) TERA2020 models Engine Configuration Block Fuel DOC Noise Margin [EPNdB] DDTF-IC-LR -2.8% -1% +1.3 CRTF-FCC-LR -3.2% -3.6% +1.7 GTF-AC-LR -3.2% -0.5% +3.5 IRA-GTF-LR -5.7% -2.0% +0.8 DDTF-IC-SR -7.4% -6.7% +3.5 CRTF-FCC-SR -6.4% -4.5% +3.5 GTF-AC-SR -5.7% -4.4% +6.0 This table shows the best engines for block fuel improvements achieved by TERA2020 optimization studies. Different design constraints come in to play as the various engine types are scaled. Note the original (non-optimized engines) were designed for a set of thrust requirements that were completely reassessed in the TERA2020 study. Takeoff distance and time to height constraints were more easily met on the SR aircraft and this has resulted in greater reductions in thrust, block fuel and DOC for the NEWAC SR engines. This table assumes that all component and systems technology targets set in NEWAC will be met, however TERA2020 sensitivity study results can be used to assess the impact of missing some of the technology targets Rolls-Royce plc and NEWAC 10

11 Intercooled engines and SP3 technologies Bypass duct offtake and LP ducting (Direct drive fan) Intercooler modules LDI combustor Intercase design HP ducting for intercooler HP compressor aerodynamics HP compressor tip injection and tip clearance control 2010 Rolls-Royce plc and NEWAC 11

12 Intercooled engine technology assessment SP3 Technologies: Improved IPC exit and HPC entry ducts for intercooler, designed and tested LP bypass offtake duct experiments completed, including bled diffuser testing Improved intercooler matrix entry and exit geometry, flow distribution to reduce losses Prototype intercooler modules designed, analyzed and manufactured (together with some limited testing) Whole Engine Mechanical Model (WEMM) studies to ensure the intercooled engine core has adequate stiffness to maintain tip clearances Intercooled engine intercase: alternative aero designs thermo-mechanically analyzed HPC rig test to improve efficiency and to demonstrate adequate surge margin HPC tip blowing system demonstration HPC passive clearance control experiments Status: Performance targets met Performance targets met Enabling technologies to reduce intercooler volume and x-section Predicted losses exceed the original targets * HPC casing distortion now greatly reduced relative to original design * OK for stress, stiffness/weight issue still being addressed * Surge margin OK, performance targets 90% met * Successful test Tests ongoing * Potential for 4% CO 2 reduction is not yet demonstrated because these four technologies have not met all their performance or weight targets 2010 Rolls-Royce plc and NEWAC 12

13 IRA engine and technologies (Geared fan) Improved centrifugal compressor Installation of recuperator modules optimized Alternative compressor designs LPP combustor 2010 Rolls-Royce plc and NEWAC 13

14 IRA engine SP2 technology status Optimised radial HP compressor for improved efficiency at lower weight No stability loss New inlet hub/tip ratio Radial/axial diffuser to suit ducting Recuperator and hot nozzle geometry and arrangement to reduce hot flow losses Minimise loss for fixed matrix geometry: Modified exchanger and nozzle geometry Adapted flow guidance Resized heat exchanger Design and integration 2010 Rolls-Royce plc and NEWAC 14

15 Active core engine and SP4 technologies Active surge control Active Cooling Air Cooling: heat exchangers, valves, new combustor case etc. PERM or LDI combustor (Geared fan) Active tip clearance control system 2010 Rolls-Royce plc and NEWAC 15

16 Active core engine technology assessment SP4 Technology Targets: Active Cooling Air Cooling Cycle benefit from 35% reduced cooling air mass flow Status: Basic test of heat pick-up Partly achieved * +1% improved turbine efficiency Partly achieved * Smart HPC technologies: +1.5% improved compressor efficiency +15% surge margin Active surge control with air injection Active clearance control - thermal Active clearance control - mechanical adequate surge margin Combined benefits -4% SFC -1% weight Demonstration on two different rigs Validated by rig test System studies only Demonstrated on static rig test Largely achieved, but over-weight * Potential for 4% CO2 reduction has not been fully demonstrated (the technologies do not consistently benefit all phases of flight) 2010 Rolls-Royce plc and NEWAC 16

17 Flow controlled core SP5 technologies (Counter-rotating fan and LP turbine) Aspirated blading Advanced HP compressor design Tip flow control Improved rotor path lining PERM or LDI combustor Active stall control 2010 Rolls-Royce plc and NEWAC 17

18 Flow controlled core technology assessment SP5 Technology Targets HPC high-speed rig test with tip flow control Aspiration on blade profiles to enable blade count reduction Active stall control by fast acting valves Stall control by tip flow recirculation (advanced casing treatment concepts) Rub management Development of an improved abradable material Status Significant efficiency gain demonstrated Assessment shows a modest efficiency benefit Significant improvement in surge margin but with some weight penalty Second round assessment shows a useful improvement in surge margin, with less weight penalty than the fast acting valve system The model of the abradable and wear is being correlated Rub test comparisons with a baseline material are completed 2010 Rolls-Royce plc and NEWAC 18

NEWAC lean combustion technologies 4 core concepts 3 Injection Systems Concepts Scientific approach

Sub-atmospheric sector Low power sector Medium power sector High power single sector TRL 3-4

emissions High power performance (thermoacoustic behaviour, circumferential instability TRL 5-6 LDI

19 NEWAC lean combustion technologies 4 core concepts 3 Injection Systems Concepts Scientific approach SP2 (IRA) SP3 (IC) SP4 (AC) SP5 (FCC) LP(P) LDI PERM Injection System Single sector rigs Sub-atmospheric sector Low power sector Medium power sector High power single sector TRL 3-4 Combustor Full annular testing Sub-atmospheric and atmospheric light-around Low power efficiency and emissions High power performance (thermoacoustic behaviour, circumferential instability TRL 5-6 LDI Lean Direct Injection PERM Partial Evaporation & Rapid Mixing LPP Lean Premixing Pre-vaporizing 2010 Rolls-Royce plc and NEWAC 19

20 DPNOx/Foo, g/kn NEWAC Cycles: Interim NOx Emission Prediction based on 1st FANN (LDI) and 1st injection system tubular combustor test results (PERM and LPP) OPR - Overall Pressure Ratio at Takeoff NOx CAEP2 limit LDI (30% CAEP2) PERM (35% CAEP2) LPP (40% CAEP2) IC - LR, LDI IC - SR, LDI FCC - LR, LDI AC - LR, LDI AC - SR, PERM FCC - SR, PERM IRA - LR, LPP 2010 Rolls-Royce plc and NEWAC 20

21 SP1 Conclusions: overall fuel-burn assessment Engine Concept High OPR Intercooled engine Intercooled and Recuperated engine Active Core engine Flow controlled Core engine NEWAC WP1.2 Study engines Status re. Fuel Burn at Fixed Thrusts NEWAC -4% target is not met yet because of weight and drag penalties. A lighter and more compact intercooler installation is needed. Some SP3 technology can apply to other engines types NEWAC target for -2% fuel burn relative to the CLEAN engine is achieved NEWAC -4% targets nearly achieved, with the ACAC technology giving the biggest benefit NEWAC -3% fuel burn targets forecast to be met for LR engine and nearly met for SR engine The best combinations of technologies will come close to meeting the NEWAC -6% CO2 target 2010 Rolls-Royce plc and NEWAC 21

Whole Engine Integration

Sub Project 1 Whole Engine Integration Andrew Rolt, Rolls-Royce plc. European Engine Technology Workshop Warsaw, SP1 Whole Engine Integration Introduction and Objectives Development of the four advanced