Jet fuel and additive clearance: Powerplant

Transcription

1 Jet fuel and additive clearance: Powerplant 2 Content Overall objectives of process Impact of fuels/additives Risk identification and mitigation Testing requirements Future challenges and supporting R&D Summary 3 Fuel Impact On Gas Turbine. Ongoing Future Engines Fuel Behaviour Deposition Airworthiness Prediction (coking) Certification Hot-End Life Maintenance Emissions Profile Performance Operability Fuel Consumption Physical Fuel/System Material Legacy Engines Maximising Chemical Compatibility Performance XWB cutaway courtesy of Rolls-Royce plc 1

2 4 Fuel-Engine Partnership Engine certification Operate on Jet A/A-1 fuels - World-wide standard Ensure safety, emissions, performance and durability Fuel specification Composition properties and performance Allowable source materials and processes Quality Assurance Fuel outside scope require testing and certification Fuel has to be drop-in to be viable 5 Overview of processes Industry wide processes, Defence Standard, Other specifications Engine OEM internal processes Management of change Ext airworthiness, quality assurance and obligations of Chief Engineer(s). Processes run in parallel 6 OEM perspective: Process objective Engines certified on fuels and additives defined at time of type certification Fuels and additives are an operational limitation Approved fuels/additives defined in engine documentation cascades to airframe operator manuals Ext. airworthiness requires management of change Fuels and/or Additives shown to be drop-in i.e. technically equivalent to existing (conventional) fuels and/or additives can be approved on the basis that engine certification remains valid 2

3 7 EASA and FAA requirements Control of fuels/additives integral part of Design Authority approval Recent missives re-iterate this responsibility FAA EASA PART 33 AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Fuel system. Advisory Circular AC No 20-24C (30/6/14) Certification Specifications for Engines. CS-E 560 Fuel System EASA - Certification Memorandum: EASA CM- PIFS-009 Iss 1. (28/02/13) Certification of Alternative Fuels Industry Qualification ( D4054) Drop-In Fuel D7566 Spec FAA Certification New Oper Limitation Non-Drop-In Fuel New Spec (e.g., UL avgas) Unchanged Operating Limitation Engine Operating Limitations Aircraft Operating Limitations Aircraft Flight Manual Slide Courtesy of Mark Rumizen - FAA D4054 Process TIER 1 TIER 2 TIER 3 TIER 4 Specification Specification Fit-For-Purpose Review & Ballot Accept Reject Re-Eval As Required Specification Balloting Process Component/Rig/APU Engine/APU Testing Testing OEMs Are Primary Gatekeepers of Process Research Report OEM Review & Approval Slide Courtesy of Mark Rumizen - FAA 3

4 D4054 Detailed Process Flow Rational risk identification and mitigation process OEMs run internal processes in parallel. OEM approval signifies: 1. Approval to update specification 2. Approval to use updated fuel in hardware (ongoing airworthiness) Key stakeholder engagement and resources are a key issue Extract from D4054 Fuel/Fuel Additive Qualification within OEM Stakeholders Refiners OEM Fuel and Additive Evaluation Process Purpose: Compliance with OEM Quality Assurance and Meet Ext. Airworthiness Requirements D4054 Process Core Generic Technical Info + Usage Definition Hardware Specific Acceptance Airframers Engine OEMs Fuel/Add Vendor Includes: - Spec props - Rig testing - Engine testing D4054 Research Report Yes OEM Risk Assessment D1655 Ballot Yes/No Spec Authority Airworthiness Authority No No Yes Internal Formal Accept or Reject Fuel Handlers Risk Mitigation Inc. supply chain and airframe interface Satisfactory completion of the above delivers generic industry approval Specific risk assessment/mitigations and/or documentation changes are required to substantiate use in OEM products. OEM specific issues or proprietary work requirement No 12 Testing HiRets AFTSTU Hot-End Matls Elasticon APU. Not to scale!! 4

5 13 Challenges Number of new entrants and pressure on resources Expansion of acceptable fuel envelope Additives with unique functionality Time and cost of process Novel fuel blend challenge 14 Fuel specifications have circa 22 properties (nearly same as dart board!) Most fuels Fall well within limits and in a typical range. Spec parameter relationships are established typical. Centre of target is comfort zone What about fuels that meet spec. but Have marginal properties Unusual relationships Need unique spec. tests Statistical occurrence? Examples of key differences 15 Novel Blend Type Unusual Aspect Impact FT and HEFA Low density Inc. Energy/unit mass (+1%) lower energy/unit vol (-2%) Aircraft loading calculations, engine control system capacity Commercial issues FT and HEFA Lower aromatics Reduced emissions and system compatibility Total/Amyris(SIP) Single molecule Presence of Farnesene FT, HEFA, SIP Flat distillation Alt relight Synthetic Aromatics All Synthetics Most synthetics 1, 2 or 3 aromatic molecules only High cycloparaffins Water solubility, air solubility, transport properties, dielectric const Composition envelope Lack of natural anti-oxidant Lubricity and low sulphur low antioxidancy Physical props and alt relight Inc viscosity cold start Spec limit and compatibility Test methodology Aromatic level equivalence Physical properties and combustion Require risk mitigation.e.g. tank guaging Test methodology applicability Additives required Control and/or additives required Engine endurance 5

6 16 Novel additive risk assessment Validation of functionality under all in-service conditions Risk of under/over dosing New chemistry.. Active ingredients and solvent/stabilisers Risk of side-effects ( no harm testing) Impact on all properties affected by trace compounds Material compatibility and hot-end impact Compatibility with other additives 17 R&D supporting activity Fuel/Additive centric industry activity Low TRL fuel/additive concepts e.g. ALFABIRD, SWAFEA, FAA-CLEEN Evaluation/Approval of new fuels/additives/production processes Due diligence of approved fuels Support to industry programmes e.g. FAME, PDR, Aquarius R&D Methodology and Fundamental Understanding Evaluation and Approval streamlining of process Thermal Stability, Combustion/Emissions, Seal Performance others? Modelling and prediction (cost/time reduction) - Jetscreen Fuel property envelope expansion for novel fuels Future spec fuels low sulphur, high stability, low aromatics etc etc Adv A/C technology vs fuel as an enabler or commodity (design limit) 18 Academic themes Effect of Scale on results. Development of robust models applicable at a range of scales (lab, demonstrator -> in service) Fuel chemistry specific models to replace current simplistic mono-component models for fit for purpose tests (beyond spec.) Development of analytical capability - standard (industry) and novel (unis) Recommendations for reverse calculated fuel properties dream fuel Mechanisms for thermal degradation and breakdown Complex chemistry of refined fuel and contrast with alternative fuels Development of combustion measurement devices Optical thermometers (SGB) Flame diagnostics using stereo imaging and post processing 6

7 Summary Changing a fuel specification could impact on engine certification OEMs must assure that a new fuel/additive does not affect performance, certification, ongoing airworthiness or cost of ownership drop-in Defined industry and OEM internal processes ensure good management of change Reducing cost/timescales and reducing risk requires further R&D 19 7