Browsing by Author "Mourouzidis, Christos"
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Item Open Access Abating CO2 and non-CO2 emissions with hydrogen propulsion(Cambridge University Press (CUP), 2024-04-02) Mourouzidis, Christos; Singh, G.; Sun, X.; Huete, Jon; Nalianda, Devaiah; Nikolaidis, Theoklis; Sethi, Vishal; Rolt, Andrew Martin; Goodger, E.; Pilidis, PericlesThis contribution focuses on the abatement with hydrogen of CO2 and non-CO2 emissions. It is agenda-setting in two respects. Firstly, it challenges the globally accepted hydrocarbon sustainable aviation fuel (SAF) pathway to sustainability and recommends that our industry accelerates along the hydrogen pathway to ‘green’ aviation. Secondly, it reports a philosophical and analytical investigation of appropriate accuracy on abatement strategies for nitrogen oxides and contrails of large hydrogen airliners. For the second contribution, a comparison is made of nitrogen oxide emissions and contrail avoidance options of two hydrogen airliners and a conventional airliner of similar passenger capacity. The hydrogen aircraft are representative of the first and second innovation waves where the main difference is the weight of the hydrogen tanks. Flights of 1000, 2000, 4000 and 8000 nautical miles are explored. Cranfield’s state of the art simulators for propulsion system integration and gas turbine performance (Orion and Turbomatch) were used for this. There are two primary contributions to knowledge. The first is a new set of questions to be asked of SAF and hydrogen decarbonising features. The second is the quantification of the benefits from hydrogen on non-CO2 emissions. For the second generation of long-range hydrogen-fuelled aircraft having gas turbine propulsion, lighter tanks (needing less thrust and lower gas temperatures) are anticipated to reduce NOx emissions by over 20%; in the case of contrails, the preliminary findings indicate that regardless of the fuel, contrails could largely be avoided with fuel-burn penalties of a few per cent. Mitigating action is only needed for a small fraction of flights. For conventional aircraft this penalty results in more CO2, while for hydrogen aircraft the additional emission is water vapour. The conclusion is that our research community should continue to consider hydrogen as the key ‘greening’ option for aviation, notwithstanding the very significant costs of transition.Item Open Access Ammonia for civil aviation: a design and performance study for aircraft and turbofan engine(Elsevier, 2024-04-06) Sasi, Sarath; Mourouzidis, Christos; Rajendran, David John; Roumeliotis, Ioannis; Pachidis, Vassilios; Norman, JustinThe 2050 net zero targets for aviation to decarbonize the industry means that solutions need to be delivered that can help achieve those targets. Transitioning to zero carbon aviation fuel is an effective solution to achieve those targets. This research article aims to highlight the potential design and performance implications of using Ammonia as a zero-carbon fuel for civil aviation through a retrofit case study conducted for an Airbus A350-1000 equivalent aircraft. The impacts on both turbofan design and aircraft payload-range capability are presented. A feasibility study of using Ammonia as a Hydrogen carrier for civil aviation is also presented. The turbofan design impacts, and payload range capability are assessed using Cranfield University’s in-house gas turbine performance tool TURBOMATCH and NASA FLOPS respectively. A 3-point turbofan cycle design strategy is utilized for redesigning turbofan engine cycles using Ammonia as a fuel. Ammonia fuel conditioning assessment is made using REFPROP to investigate its impact on turbofan design. Utilizing pure Ammonia as an aircraft fuel can provide significant turbofan redesign opportunities. Fuel conditioning assessment revealed that for a 430 kN thrust class engine, 2.1 MW of thermal power is required to condition Ammonia fuel at take-off. As a result, various strategies to condition the fuel and its significant impact on turbofan design are presented indicating fuel conditioning as a major design driver for Ammonia fuelled turbofan engines in the future. Although upon initial preliminary assessment, Ammonia utilized as a Hydrogen carrier showcased potential by providing additional mission range capability when compared to a pure Ammonia burning aircraft, the significant thermal energy required to crack (decompose) Ammonia into Hydrogen highlighted the challenges at aircraft mission level and Hydrogen turbofan design implications. It is found that energy requirement (power) to crack Ammonia into Hydrogen are significant which is approximately an order of magnitude higher than Ammonia fuel conditioning itself.Item Open Access Assessment of performance boundaries and operability of low specific thrust GUHBPR engines for EIS2025(American Society of Mechanical Engineers, 2022-04-25) Mo, Da; Roumeliotis, Ioannis; Mourouzidis, Christos; Kissoon, Sajal; Liu, YixiongThis paper aims to develop a robust design process by approaching the performance boundaries and evaluating the operability of the pursued geared turbofan engine with low specific thrust for EIS 2025. A two-spool direct-drive turbofan (DDTF) engine of EIS 2000 was improved according to aircraft specifications and technology boundaries in 2025. A series of optimized engines with consecutive fan diameters were established to seek the ideal engine by balancing SFC, weight and mission fuel burn. The fan diameter was proved to be a decisive factor for lowering SFC and energy usage. The cycle design optimization process achieved a thermal efficiency of approximately 52%, and a propulsive efficiency of 79.5%, which is 8.19% increase in propulsive efficiency by enlarging fan diameter from 1.6m to 1.9m. Meanwhile, the 1.9m-fan diameter engine achieved a reduction in SFC and fuel burn of 7.47% and 6.58% respectively which offers an overall reduction of 30.82% in block fuel burnt and CO2 emission compared to the DDTF engine. A feasibility check verified the viability of the designed optimum engine in terms of fan tip speed, stage loading and AN2. Dynamic simulation offered a deep understanding of transient behaviour and fundamental mechanism of the geared turbofan engine. An important aspect of this paper is the use of advanced CMC materials, which led to an improvement of 4.92% in block fuel burn and 2.93% in engine weight.Item Open Access Assessment of the performance boundaries of very low specific thrust direct-drive turbofan engines at aircraft level for EIS 2025(GPPS Chania20, 2020-09-07) Kissoon, Sajal; Zhang, Fan; Mourouzidis, Christos; Roumeliotis, Ioannis; Pachidis, VassiliosWithin the past decade, concerns over the environmental impact of civil aviation have pushed the research community towards the development of more efficient propulsion technology, which delivers a lower carbon and NOx footprint. The current progress achieved in the various specialised disciplines creates the need to redefine the performance barrier achievable by 2025 state-of-the-art aero-engines. This paper summarises some of the latest advancements within the gas turbine research community on the performance modelling and analysis of very low dspecific thrust direct-drive turbofan engines for EIS 2025. Engine and aircraft performance models were used to predict the extent of fuel burn reduction at aircraft level that could be achieved by reducing the engine specific thrust level , increasing operating pressure and temperature levels and applying technology factors representing a step beyond current state-of-the-art. The models represented modern three-spool direct-drive turbofans powering a typical A350XWB-type aircraft. The outputs of the engine design of experiments (DoE) exercise resulted in three most promising candidates. Targeting EIS in 2025, the final optimum design showed 14.81% block fuel improvement for a representative long (7000nm) range mission, accompanied by 30.9% penalty on engine weight. These results propose that with current technology level, at the lower end of the specific thrust range, there is still available design space for the direct-drive turbofan architectureItem Open Access Assessment of thermo-electric power plants for rotorcraft application(ASME, 2019-10-01) Roumeliotis, Ioannis; Mourouzidis, Christos; Zafferetti, Mirko; Deniz, Unlu; Broca, Olivier; Pachidis, VassiliosThis paper assesses a parallel electric hybrid propulsion system utilizing simple and recuperated cycle gas turbine configurations. An adapted engine model capable to reproduce a turboshaft engine steady state and transient operation is built in Simcenter Amesim and used as a baseline for a recuperated engine. The transient operation of the recuperated engine is assessed for different values of heat exchanger effectiveness, quantifying the engine lag and the surge margin reduction which are results of the heat exchanger addition. An oil and gas mission of a twin engine medium helicopter has been used for assessing the parallel hybrid configuration. The thermo-electric system brings a certain level of flexibility allowing for better engine utilization, thus firstly a hybrid configuration based on simple cycle gas turbine scaled down from the baseline engine is assessed in terms of performance and weight. Following the recuperated engine thermo-electric power plant is assessed and the performance enhancement is compared against the simple cycle conventional and hybrid configurations. The results indicate that a recuperated gas turbine based thermo - electric power plant may provide significant fuel economy despite the increased weight. At the same time the electric power train can be used to compensate for the reduced specific power and potentially for the throttle response change due to the heat exchanger addition.Item Open Access Evaluation of a collaborative and distributed aircraft design environment, enabled by microservices and cloud computing(AIAA, 2023-01-19) Chen, Xin; Isoldi, Adriano; Riaz, Atif; Mourouzidis, Christos; Keskin, Akin; Smith, Dale; Guenov, Marin D.; Pachidis, VassiliosPresented in this paper are the outcomes from the evaluation of a distributed aircraft design environment, based on microservices and cloud computing. The evaluation was performed on a representative airframe-engine optimization case study, including the engine, wing aero-structural geometry, and high-lift devices. The (computational) design process involved multiple distributed design teams and design tools. The latter were implemented with different programming languages and deployed on the Azure cloud service. As a benchmark, the same case study was performed using the traditional email/document-based approach to design collaboration. Compared with the traditional collaboration, the cloud-based approach substantially reduced the time for design iterations between the design teams. This was mainly due to the fast remote access of models/tools on the cloud and automation of data exchange. Also, the exercise indicated that the cloud-based approach is more flexible with regard to orchestrating the computational workflows and optimization studies, while protecting the Intellectual Property (IP) of the collaborating partners.Item Open Access Impacts of alternative aviation fuels on engine cycle design and aircraft mission capability(American Society of Mechanical Engineers, 2023-09-28) Sasi, Sarath; Mourouzidis, Christos; Roumeliotis, Ioannis; Nikolaidis, Theoklis; Pachidis, Vassilios; Norman, JustinRecent 2050 net zero targets for aviation have sparked interest among the industry players to seek alternative aviation fuels as a pathway for the immediate alleviation of its carbon footprint. This paper aims to shed light on the opportunities and challenges that zero & low-carbon alternative fuels can provide from a technical standpoint. To address this aim, candidate fuels for aviation were selected from five broad classes of fuels. Then, a preliminary thermodynamic engine cycle design space exploration of a modern three spool turbofan is conducted to identify the fuel impact on cycle performance. Following that, an integrated Engine-Aircraft mission assessment for a Boeing 787 style aircraft with a three spool turbofan is conducted to assess performance at the mission level and explore opportunities and challenges for both powerplant and aircraft, accounting for fuel storage. Finally, an investigation of the opportunities available for the proposed fuels to be used as a heat sink is presented. The results indicate that zero-carbon fuels expand the design space for the powerplant cycle, allow for higher BPR, lower energy specific fuel consumption, lower peak cycle temperatures compared to the rest of the fuels, and provide significant cycle redesign opportunities. On a mission level, cryogenic fuels are penalized for block energy consumption due to the significant weight and size of the fuel storage system, while liquid alternative fuels are comparable to kerosene in terms of emissions and block energy consumption. Concerning Hydrogen, Methane, and Ammonia, the thermal power requirement for fuel conditioning (pressure and temperature rise) is calculated to be 2.2MW, 1.3MW, and 1MW respectively for a 240kN SLS thrust class engine during take-off.Item Open Access Integrated hybrid engine cycle design and power management optimization(American Society of Mechanical Engineers, 2023-09-28) Ghelani, Raj; Roumeliotis, Ioannis; Saias, Chana Anna; Mourouzidis, Christos; Pachidis, Vassilios; Bacic, Marko; Norman, JustinA novel integrated gas turbine cycle design and power management optimization methodology for parallel hybrid electric propulsion architectures is presented in this paper. The gas turbine multi-point cycle design method is extended to turboprop and turbofan architectures, and several trade studies are performed initially at the cycle level. It is shown that the maximum degree of electrification is limited by the surge margin levels of the booster in the turbofan configuration. An aircraft mission-level assessment is then performed using the integrated optimization method initially for an A320 Neo style aircraft case. The results indicate that the optimal cycle redesigned hybrid electric propulsion system (HEPS) favors take-off and climb power on-takes while optimal retrofit HEPS favor cruise power on-takes. It is shown that for current battery energy density (250 Wh/Kg), there is no fuel burn benefit. Furthermore, even for optimistic energy density values (750 Wh/kg) the maximum fuel burn benefit for a 500 nm mission is 5.5% and 4% for redesigned and retrofit HEPS, respectively. The power management strategies for HEPS configurations also differ based on gas turbine technology with improvement in gas turbine technology showing greater scope for electrification. The method is then extended to ATR 72 style aircraft case, showing greater fuel burn benefits across the flight mission envelope. The power management strategies also change depending on the objective function, and optimum strategies are reported for direct operating cost or fuel burn. The retrofit case studies show a benefit in direct operating cost compared to redesigned case studies for ATR 72. Finally, a novel multimission approach is shown to highlight the overall fuel burn and direct operating cost benefit across the aircraft mission cluster.Item Open Access Preliminary design of next generation Mach 1.6 supersonic business jets to investigate landing & take-off (LTO) noise and emissions–SENECA(IOP Publishing, 2023-06-28) Mourouzidis, Christos; Del Gatto, Dario; Adamidis, Stylianos; Villena Muñoz, Cristina; Lawson, Craig; Martinez Corzo, B.; Leyland, P.; Marsh, D.; Lim, L.; Owen, B.With the approach of next generation supersonic transport entry into service, new research activities were initiated to support updates on ICAO regulations and certification processes for supersonic transport vehicles. Within this context, the EU Horizon 2020 SENECA project has been launched to investigate the levels of noise and gaseous emissions in the vicinity of airports as well as the global climate impact of next generation supersonic civil aircraft. This paper introduces some of the preliminary outcomes of this investigation. It presents the preliminary design and performance analysis of a Mach 1.6 business jet, following an integrated aircraft-engine design approach. The preliminary design was performed accounting for the limitations posed by future environmental restrictions on respective subsonic vehicles. The market space and mission route definition exercise assumed only "over-sea" supersonic operations, while for "over-land", only subsonic operations where allowed. Parametric studies on engine integrated design demonstrated modest core temperatures while cruising and the significant impact of engine installation on performance. At this first design iteration, assuming current state of the art technology, the Mach 1.6 business jet showed good potential to satisfy the predicted mission requirements while respecting the environmental constraints in terms of Landing & Take-Off (LTO) noise and emissions.Item Open Access Water injection on aircraft engines: a performance, emissions and economic study(ISABE, 2015-10-22) Mourouzidis, Christos; Igie, Uyioghosa; Pilidis, Pericles; Singh, RitiAlthough aviation based emissions are not the major sources of atmospheric pollution, their impact around the airport vicinity and the increase in air transport makes it a concern. Water injection on aircraft engines can reduce NOx emissions around the airports significantly. This has been demonstrated in research study by NASA Glenn Research Center in collaboration with Boeing Company. The aim of this study is to investigate the performance, emissions and economic aspects of water ingestion for medium and high bypass ratio jet engines using Cranfield University in-house gas turbine simulation software. British Airways was chosen as a representative airline to be used as case study in order to examine the effects of this technology. Performance and emissions models were developed for the most popular aircraft of the fleet, along with their engines. The simulations were focused on the take-off phase of the aircraft, injecting water in the low pressure compressor (LPC) and the combustor, for different water-toair ratios. The results were optimized in terms of fuel burn and verified against the respective results from the NASA study [1]. Finally, an economic model was developed in order to evaluate the monetary impact of these systems, from the point of view of an airliner with a specific number of aircraft in their fleet. The main outcomes of this study show that LPC water injection can provide more than 10% take-off thrust augmentation in a standard day when in hot days it can exceed 25%. Alternatively, the specific fuel consumption at take-off can reach a 10% reduction, for a fixed take-off thrust level. On the other hand, combustor water injection penalizes the engine performance in all cases. Additionally, depending on the point of injection and the water to air ratio, NOx emissions reduction ranges between 25%-85%. Finally, for the case study examined here, the value for the annual monetary benefit due to water injection can reach 599,654£, without taking into account the airport emission based fees. An investment of such sort could present a dynamic payback period of 7.5 years, assuming constant market interest of 8% and 10 years operational life of the equipment.