1 5 A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 Canada, Innovative Vehicle Institute, and the Governments of Canada and Quebec on a Regional Hybrid Electric Flight Demonstrator based on the De Havilland Canada Dash 8-100 to mature hybrid-electric technologies. This engine demonstration will feature advanced electric and thermal engine technologies may yield up to 30% improvement in fuel efficiency relative to thebaseline thermal engine. Aground demonstration of these advanced technologies was successfully executed in 2022. A flight demonstration for these hybrid-electric technologies is scheduled for 2024. The learning from these demon- strations will be applied to hybrid- electric engines for future single-aisle applications. These advanced propulsion systems, which would include foundational GTF engine technologies, hybrid-electric engine technologies, a 100% SAF-compatible, advanced low emissions combustion system, and exhaust waste heat recovery technologies, would yield a step change in mission energy reduction and environmental performance. Pratt &Whitney, MTU Aero Engines AG, GKN Aerospace, and Collins Aerospace announced the formation of a consortium supported by the EU Clean Aviation Undertaking. The project under this consortium, called Sustainable Water-Injecting Turbofan Comprising Hybrid Electrics (SWITCH), is developing advanced technologies for hybrid- electric engines that enable up to a 25% improvement in fuel efficiency relative to today’s state-of-the-art aircraft engines for short- and medium-range aircraft while substantially reducing greenhouse gas emissions. These advanced technologies include hybrid-electric, advanced SAF-compatible combustors, and exhaust waste heat recovery technologies. These advanced propulsion technologies will also be evaluated for future use with the hydrogen energy carrier. Hydrogen Propulsion. Hydrogen- powered aircraft may enable the aviation industry to achieve net zero CO2 emissions by 2050. Pratt & Whitney is developing an advanced hydrogen propulsion concept called the Hydrogen Steam Injected and Intercooled Turbine Engine (HySIITE). Pratt & Whitney is evaluating the requirements of the overall propulsion system as well as that of the advanced, low NOx combustor and advanced heat exchanger component technologies under a twoyear United States Department of Energy (DOE) Office of Advanced Research Projects Agency for Energy (ARPA-E) contract. HySIITE leverages cryogenic liquid hydrogen as a heat sink to augment thermodynamic efficiency by up to 35% relative to current best-in-class commercial engines while generating thrust with zero CO2 emissions. This engine features a steam-injected combustion system to deliver low NOx emissions. Furthermore, an evaporator transferswasteheat to the cryogenically cooled liquid hydrogen to increase its enthalpy prior to injection into the combustor. In addition, a condenser capture captures and converts water vapor to support steam-injection into the combustor, intercooling of the compression system, and turbine cooling. Fig. 5 — Hybrid electric propulsion. Fig. 6 — Advanced hydrogen propulsion system. Hydrogen that is manufactured from renewable energy sources would be needed to decarbonize global aviation. However, only 0.1% of hydrogen is produced from renewable energy sources today[1]. Significant investment in the global infrastructure for commercial scale green hydrogen production is needed to achieve net zero carbon emissions in aviation by 2050. Pratt & Whitney will continue to mature the suite of advanced technologies required for hydrogen propulsion as these investments are made. CONTRAILS Condensation trails, also known as contrails, are ice clouds that form due to the mixing between an aircraft engine exhaust plumes and ambient air[10]. Contrails can create persistent cirrus clouds that may scatter shortwave solar radiation, resulting in a cooling effect, and reflect terrestrial long wave radiation, which yields a warming effect. Approximately, 5-10% of flights make 80-90% of contrails. However, the net radiative forcing from persistent contrails yields a warming effect that may exceed that of CO2 emissions[10]. The impact of non-CO 2 emissions, including contrail effects, increase the aviation industry’s environmental footprint to approximately 3.5% of global anthropogenic climate impact[1]. The probability of occurrence of a contrail is a function of the ambient air properties, aviation fuel properties, and engine efficiency. The contrail formation process is enabled by the presence of particulates around which super-saturated water vapor freezes and forms ice crystals. Most of these particulates are produced by the aircraft engine combustion process and emitted in the exhaust plume. The remaining particulates are airborne aerosols that are always present in the atmosphere. Sustainable aviation fuels that contain lower levels of sulfur and aromatic hydrocarbons may generate fewer particulate emissions in the combustion process, yielding fewer ice crystals,
RkJQdWJsaXNoZXIy MTYyMzk3NQ==