Showing papers on "Propulsion published in 2023"
TL;DR: In this paper , the authors provide an overview of recent advancements in aircraft electrification, and trends and future developments referenced to the global aviation roadmap, as well as present a scenario in which electric power must be efficiently generated, distributed, and consumed to satisfy extremely high requirements of aviation safety.
Abstract: Aviation is a significant contributor to greenhouse gas (GHG) emissions in the transportation sector. As the adoption of electric cars increases and GHG emissions due to other modes of transport decrease, the impact of air travel on environmental pollution has become even more significant. To reduce pollution and maintenance, and ensure cheaper and more convenient flights, industry and academia have directed their efforts toward aircraft electrification. Considering various types of aircraft, several frameworks have been proposed: more-electric aircraft (MEA), hybrid electric aircraft (HEA), and all-electric aircraft (AEA). In the MEA framework, propulsion is generated by a conventional jet engine; however, all secondary systems (hydraulic, pneumatic, and actuation) are electrified. By further increasing electrification, electric motors can provide propulsion with the electric power supplied by the conventional engine (i.e., HEA) or from electrical energy storage (i.e., AEA). Power electronics and electrical machines play a key role in this scenario in which electric power must be efficiently generated, distributed, and consumed to satisfy extremely high requirements of aviation safety. This article provides an overview of recent advancements in aircraft electrification, and trends and future developments referenced to the global aviation roadmap.
17 citations
TL;DR: In this article , the self-propulsion performance of an ice-strengthened Panamax bulk carrier in brash ice channel was investigated using the CFD-DEM coupling method.
16 citations
TL;DR: In this article , the authors reviewed the published work on hybrid solid oxide fuel cells (SOFC) and internal combustion engines (ICE) considering various configurations, and found that integrated SOFC-ICE systems are promising candidates over conventional engines and stand-alone SOFCs to be used in stationary power generation and heavy-duty applications (e.g., marine and locomotive propulsion systems).
Abstract: There has been a growing demand to develop new energy conversion devices with high efficiency and very low emissions for both power and propulsion applications in response to the net zero-carbon emission targets by 2050. Among these technologies, solid oxide fuel cells (SOFCs) have received attention due to their high electrical efficiency (above 60%), fuel flexibility, low-emission, and high-grade waste heat, which makes them particularly suitable for a large number of applications for power and propulsion systems. The higher operating temperatures make SOFCs suitable candidates for integration with an additional power generation device such as an internal combustion engine (ICE) by (a) using the residual fuel of the anode off-gas in the engine, which further increases overall system efficiency to values exceeding 70%, (b) decreasing combustion inefficiencies and (c) increasing waste heat recovery. This paper reviews the published work on hybrid SOFC-ICE systems considering various configurations. It has been found that integrated SOFC-ICE systems are promising candidates over conventional engines and stand-alone SOFCs to be used in stationary power generation and heavy-duty applications (e.g., marine and locomotive propulsion systems). The discussion of the present review paper provides useful insights for future research on hybrid electrochemical-combustion processes for power and propulsion systems. • A critical review of the latest progress in research and development of hybrid SOFC-ICE systems. • Various design and operating characteristics of the hybrid systems are reviewed. • Hybrid SOFC-ICE systems are promising candidates for stationary power generation and marine applications. • Future trends and challenges on technological aspects are discussed.
12 citations
19 Jan 2023
TL;DR: In this paper , two parametric parallel hybrid architectures are proposed and applied on both size classes: Architecture 1 has two propellers, each driven by an engine and an electric motor in parallel, and allows in-flight recharging; Architecture 2 has four propellers and allows parallel operation during the cruise.
Abstract: This paper evaluates the potential benefits of applying hybrid parallel propulsion architectures to future turboprop aircraft that are expected to enter into service in 2030. Two baseline aircraft models are established by infusing viable 2030 airframe and engine technologies on state-of-the-art 19-passenger and 50-passenger aircraft models. Two parametric parallel hybrid architectures are proposed and applied on both size classes: Architecture 1 has two propellers, each driven by an engine and an electric motor in parallel, and allows in-flight recharging; Architecture 2 has four propellers, each driven by either an engine or an electric motor, and allows parallel operation during the cruise. A design space exploration is conducted on the powertrain design variables and the electric component key performance parameters. A constrained optimization implies that Architecture 1 and 2 can achieve fuel savings of about 2.6% and 6.6%, respectively, given 2030 electric component technology assumptions. Electric taxi consistently results in fuel saving when battery technology is beyond the projected 2030 level. Preliminary sensitivity studies show that the performance of Architecture 2 is more sensitive to the battery technology compared to Architecture 1 due to its extensive use of battery energy during the cruise.
9 citations
19 Jan 2023
TL;DR: In this paper , a framework for large-scale multi-fidelity modeling and optimization of electric vertical takeoff and landing concepts (eVTOLs) is presented, which is based on a geometry-centric approach to multidisciplinary design optimization.
Abstract: This paper presents a framework under development for enabling large-scale multi-fidelity modeling and optimization of electric vertical takeoff and landing concepts (eVTOL). The key features of the framework are a geometry-centric approach to multidisciplinary design optimization (MDO), a modular functional-form representation of the disciplines involved in aircraft design, and fully automated derivative computations thereby allowing efficient gradient-based optimization. The framework is first presented in a general manner agnostic to the vehicle concept or the physics-based analyses used. The key disciplines involved in the design of eVTOL aircraft and the couplings between the disciplines are described. The complex multidisciplinary nature of the design is emphasized. The framework is then applied to the design of the NASA lift-plus-cruise concept. Low-fidelity solvers of aerodynamics, propulsion, structural estimation, acoustics, powertrain, and battery are coupled together. The optimization considers 108 design variables and 16 constraints. It is shown that MDO considering geometric variables results in a design with lower gross mass than when the geometric variables are not considered. The optimization turnaround time of 30 minutes on a standard workstation demonstrates the capabilities of fully-coupled large-scale MDO using gradient-based optimization. The framework is under development and an open-source version will be released in the near-future.
6 citations
TL;DR: In this article , an exploration of three major technology streams for energy storage: batteries, fuel cells, and turbine internal combustion engine generators, also including possible combinations of those technologies was carried out through the execution of several designs of experiments aiming at the identification of the most promising solutions in terms of aircraft configuration for three different time horizons.
Abstract: The environmental impact of aviation in terms of noise and pollutant emissions has gained public attention in the last few years. In addition, the foreseen financial benefits of an increased energy efficiency have motivated the transport industry to invest in propulsion alternatives. This work is collocated within the Clean Sky 2 project GENESIS, focused on the environmental sustainability of 50-passenger hybrid-electric aircraft from a life-cycle-based perspective to support the development of a technology roadmap for transitioning towards sustainable and competitive electric aircraft systems. While several studies have already focused on the definition of possible aircraft designs combining several propulsion systems, the novelty of the present work is to consider technology forecasts and more comprehensive indicators in the design phase. These include the performance and emissions on a 200 nmi typical mission, which reflects the most economically attractive range for aircraft in the regional class. The work proposes a complete exploration of three major technology streams for energy storage: batteries, fuel cells, and turbine internal combustion engine generators, also including possible combinations of those technologies. The exploration was carried out through the execution of several designs of experiments aiming at the identification of the most promising solutions in terms of aircraft configuration for three different time horizons: short-term, 2025–2035; medium-term, 2035–2045; and long-term, 2045–2050+. As a result, in the short-term scenario, fuel energy consumption is estimated to be reduced by around 24% with respect to conventional aircraft with the same entry-into-service year thanks to the use of hybrid propulsive systems with lithium batteries. Fuel saving increases to 45% in the medium-term horizon due to the improvement in the energy density of storage systems. By the year 2050, when hydrogen fuel cells are estimated to be mature enough to completely replace kerosene-based engines, the forthcoming hybrid-electric aircraft promise no NOx and CO2 direct emissions, while being approximately 50% heavier than conventional ones.
6 citations
TL;DR: In this article , the design spaces of a thin-haul and a regional aircraft with parallel hybrid-electric propulsion architectures for a 2030 entry into service date were explored for a 19-and a 50-passenger aircraft based on publicly available data on Beechcraft 1900D and ATR 42-600, respectively.
Abstract: This paper explores the design spaces of a thin-haul and a regional aircraft with parallel hybrid-electric propulsion architectures for a 2030 entry into service date. Notional technology reference aircraft models were developed for a 19- and a 50-passenger aircraft based on publicly available data on Beechcraft 1900D and ATR 42-600, respectively. A set of airframe and propulsion system technologies projected to reach maturity by 2030 was infused into the aircraft models. Parametric, physics-based models were created for the charge-depleting hybrid architecture. Different modes of operation were identified and parameterized with a range of design variables to investigate the feasibility and trade space for peak power shaving, climb power boosting, electric taxi, battery usage schedules, and in-flight battery recharge strategies. Thousands of electrified aircraft concepts with varying electrification, operation, and technology scenarios were sized under the same system-level requirements as their conventional counterpart. The resulting multidisciplinary design space exploration environment was used to identify the optimum vision system designs and modes of operation for the minimum block fuel-burn objective. It has been found that both vehicle classes with the charge-depleting parallel hybrid electric architecture provided fuel-burn benefits over their 2030 advanced technology counterparts under certain operational modes.
6 citations
19 Jan 2023
TL;DR: In this paper , the Parametric Energy-Based Aircraft Configuration Evaluator was used to pursue multi-objective optimization of a lift-plus-cruise urban air mobility with all-electric, hybrid-electric and turbo-electric propulsion system architectures.
Abstract: Conventional aircraft sizing methods face challenges analyzing all-electric or hybrid-electric novel aircraft configurations, such as those for urban air mobility applications. The vast design space containing both continuous and discrete design variables and competing design objectives necessitate searching for not necessarily a unique optimal design, but rather, an array of Pareto-optimal designs. This paper uses the Parametric Energy-Based Aircraft Configuration Evaluator, an aircraft sizing framework for novel aircraft and propulsion system architectures. The framework is used to pursue multi-objective optimization of a lift-plus-cruise urban air mobility with all-electric, hybrid-electric, and turbo-electric propulsion system architectures using Non-dominated Sorting Algorithm II. The optimization cases considered in this work included multiple objective functions such as gross weight, mission time, energy mass fraction, and energy used per unit distance per unit payload. Optimization was performed for single-trip distances of 80, 120, and 150 kilometers and battery specific energy levels of 350 Wh/kg and 400 Wh/kg. It revealed scenarios where a single architecture was present in the final generation and others where all three architectures were present. The results obtained afford valuable insights into the relative performance of the three architectures with regard to the multiple objectives and the trends of individual design variables within the optimized populations.
5 citations
19 Jan 2023
TL;DR: In this article , a coupled aeropropulsive design optimization framework is proposed to study the aerodynamic integration for over-wing nacelle (OWN) configurations, where the coupling behavior between the aerodynamics of the wing and the propulsion system is investigated.
Abstract: Optimal nacelle placement is critical to commercial or transport aircraft designs that use engines mounted with nacelles. Over-wing nacelle (OWN) configuration has a high potential to improve upon the conventional under-wing nacelle (UWN) configuration. OWN configurations have two critical benefits when compared to the conventional UWN configuration: 1. they ease the integration of high BPR and ultra-high BPR engines by alleviating ground clearance issues, and 2. they provide a significant amount of noise reduction because the wing blocks the noise of the fan and the jet. Despite their advantages, the OWN technology is not used in practical aircraft designs due to the difficulties in the aeropropulsive integration of the propulsion system. In this work, we propose using a coupled aeropropulsive design optimization framework to study the aeropropulsive integration for OWN configurations. The coupling behavior between the aerodynamics of the wing and the propulsion system is extremely important. Especially in OWN configurations, the propulsion system is highly influenced by the aerodynamic performance of the wing. In this paper, we address the design problem of coupling between the aerodynamic and the propulsion system. We also explore wide range of design space to achieve the best practical design. The changes in wing shape are insignificant when the OWN configuration is optimized for different FPR. Wing in OWN performs better when the propulsor is close to the wing's root; however, the overall drag increases when the propulsor is close to the root. This increases the shaft power need. In addition, nacelle placement at the aft of the trailing edge shows better performance than forward of the trailing edge of the wing. These advancements in design optimization capabilities will be critical in the future design of OWN configurations to achieve more environmentally sustainable aircraft designs.
4 citations
TL;DR: In this paper , the authors investigated the impact of certification requirements on the DEP aircraft design, taking NASA's PEGASUS concept as a use case and presented a study of certification-constrained vertical tail sizing and propulsive power split optimization.
Abstract: Distributed electric propulsion (DEP) concepts leverage the synergistic benefits of aeropropulsive coupling and improve the overall flight efficiency by placing propulsors at optimal locations, such as the wingtip. However, placing propulsors far away from the aircraft centerline may bring aircraft difficulties in complying with critical-engine-inoperative flight certification rules. To investigate the impact of certification requirements on the DEP aircraft design, this paper takes NASA’s PEGASUS concept as a use case and presents a study of certification-constrained vertical tail sizing and propulsive power split optimization. For comparison, a vertical tail retrofit study is also conducted on the ATR 42-500 aircraft using the same design space, to gain insights into the different impacts of certification constraints on the design process between conventional and unconventional aircraft. In each study, a design space exploration is performed, including a feasibility test and a multi-objective optimization. The feasibility test shows that the certification constraints yield a much smaller feasible design space for the DEP concept when compared to the conventional aircraft. Despite a much smaller feasible design space, the constrained Pareto optima of the PEGASUS still exhibit lower cruise drag coefficient, fuel burn, and operational energy cost when compared to those of the ATR 42.
4 citations
TL;DR: In this paper , an anti-hydropressure miniature cross-shaped underwater robot (CSUR) with dimensions of Φ10.9 × 6.3 cm was proposed.
Abstract: The high-pressure environment of deep-sea challenges the miniaturization of underwater robots due to the assembly of antihydropressure devices for protecting the electromagnetic motor. Here, inspired by the motion principle of jellyfish, a novel piezoelectric pulsed-jet actuator (PJA) was proposed as the power source. Six PJAs were arranged crosswise to form an antihydropressure miniature cross-shaped underwater robot (CSUR) with dimensions of Φ10.9 × 6.3 cm 3 . The numerical simulation method was adopted to analyze the propulsion mechanism, optimize the structure, and find the optimal frequency. A robot prototype was fabricated, and its motion performances were tested. The CSUR achieved floating, sinking, and hovering motions in the vertical direction and linear, rotary, and turning motions in the horizontal direction. The maximum linear velocity reached up to 47.8 mm/s (0.43 BL/s). The robot could move in a high-pressure environment of 10 MPa, and the average velocity deviations under different water pressures were less than 10%. Besides, the CSUR could move along an S-shaped path to navigate around obstacles. The proposed robot performed merits of miniature structure, good adaptability of a high-pressure environment, high agility, and maneuverability. It is potential for the CSUR to be applied in exploring, mapping, and sampling narrow areas of the deep sea.
TL;DR: In this paper , a solid oxide fuel cell turbine-less hybrid electric propulsion system is developed, in which the power consumed by the compressor comes from a fuel cell, not a turbine.
TL;DR: In this paper , the authors discussed the mission performance of regional aircraft with hybrid-electric propulsion and provided performance analyses by mission simulations tools specifically developed for hybridelectric aircraft flight dynamics, which can lead to benefits in terms of environmental performance, through savings in direct fuel consumption, or alternatively in operating terms, through a significant extension of the operating envelope.
Abstract: This article discusses the mission performance of regional aircraft with hybrid-electric propulsion. The performance analyses are provided by mission simulations tools specifically developed for hybrid-electric aircraft flight dynamics. The hybrid-electric aircraft mission performance is assessed for the design point, identified by top level requirements, and for off-design missions, within the whole operating envelope. This work highlights that the operating features of hybrid-electric aircraft differ from those of aircraft of the same category with conventional thermal propulsion. This assessment is processed by properly analysing the aircraft payload–range diagram, which is a very effective tool to assess the operating performance. The payload–range diagram shape of hybrid-electric aircraft can vary as multiple combinations of the masses of batteries, fuel and payload to be transported on board are possible. The trade-off in the power supply strategies of the two power sources to reduce fuel consumption or to extend the maximum flight distance is described in detail. The results show that the hybrid-electric propulsion integrated on regional aircraft can lead to benefits in terms of environmental performance, through savings in direct fuel consumption, or alternatively in operating terms, through a significant extension of the operating envelope.
TL;DR: In this paper , the authors describe methods to identify an integrated propulsion-airframe aerodynamic model and a decoupled propulsion model for fixed-wing aircraft with propellers using flight data.
Abstract: This paper describes methods to identify an integrated propulsion–airframe aerodynamic model and a decoupled propulsion model for fixed-wing aircraft with propellers using flight data. Propulsion aerodynamics and airframe aerodynamics for propeller aircraft are usually modeled separately, which fails to describe unavoidable interaction effects and propeller performance deviations when integrated on an aircraft. Two novel flight test system identification approaches are presented to develop flight dynamics models with improved characterization of propeller aerodynamics compared to conventional methods. Orthogonal phase-optimized multisine inputs are applied to both the control surfaces and propulsion system to generate data with high-quality information content for model identification. Propulsion explanatory variables derived from propeller aerodynamics theory combined with traditional aircraft modeling variables yield accurate aero-propulsive modeling results and provide propeller performance estimates, which are compared to isolated propeller wind tunnel data. An assessment of model adequacy using flight maneuvers withheld from model identification indicates that the models have good prediction capability. The paper describes application of these methods to a small unmanned aircraft, but the methods are generalizable to many propeller-driven aircraft.
TL;DR: In this paper , the authors used experiments and simulations to investigate the trapping of microrollers by obstacles and found that the trapping time can be controlled by modifying the obstacle size or the colloid-obstacle repulsive potential.
Abstract: It is known that obstacles can hydrodynamically trap bacteria and synthetic microswimmers in orbits, where the trapping time heavily depends on the swimmer flow field and noise is needed to escape the trap. Here, we use experiments and simulations to investigate the trapping of microrollers by obstacles. Microrollers are rotating particles close to a bottom surface, which have a prescribed propulsion direction imposed by an external rotating magnetic field. The flow field that drives their motion is quite different from previously studied swimmers. We found that the trapping time can be controlled by modifying the obstacle size or the colloid-obstacle repulsive potential. We detail the mechanisms of the trapping and find two remarkable features: The microroller is confined in the wake of the obstacle, and it can only enter the trap with Brownian motion. While noise is usually needed to escape traps in dynamical systems, here, we show that it is the only means to reach the hydrodynamic attractor.
TL;DR: In this article , a novel integration of a solid oxide fuel cell (SOFC), lithium ion batteries and a gas turbine propulsion system is proposed for a hybrid electric aircraft, where a pathway for liquid water input to the hybrid system is designed in a way to first circulate through the lithium ion battery to remove generated heat from them before it is used in the remainder of system.
TL;DR: In this article , an ultrafast microbullet based on laser cavitation that can utilize the energy of a cavitation bubble and realize its own hurtling motion is reported using high-speed photography.
Abstract: Micromotors hold great promise for extensive practical applications such as those in biomedical domains and reservoir exploration. However, insufficient propulsion of the micromotor limits its application in crossing biological barriers and breaking reservoir boundaries. In this study, an ultrafast microbullet based on laser cavitation that can utilize the energy of a cavitation bubble and realize its own hurtling motion is reported. The experiments are performed using high-speed photography. A boundary integral method is adopted to reveal the motion mechanism of a polystyrene (PS)/magnetic nanoparticle (MNP) microbullet under the action of laser cavitation. Furthermore, the influence of certain factors (including laser intensity, microbullet size, and ambient temperature) on the motion of the microbullet was explored. For the PS/MNP microbullet driven by laser cavitation, the instantaneous velocity obtained can reach 5.23 m s-1 . This strategy of driving the PS/MNP microbullet provides strong penetration ability and targeted motion. It is believed that the reported propulsion mechanism opens up new possibilities for micromotors in a wide range of engineering applications.
TL;DR: In this article , a photothermal composite of graphene and polydimethylsiloxane is used to develop controllable Marangoni propulsion for self-propelled swimming robots.
Abstract: Chemical Marangoni propulsion enables dynamic and untethered motion by generating surface tension gradient through chemical release, thereby having great potential for the development of insect‐scale self‐propelled robots. However, as the release and diffusion of chemical “fuels” are commonly uncontrollable, the Marangoni propulsion is unstable, thereby restricting robotic applications. Herein, the laser fabrication of superhydrophobic swimming robots to develop controllable Marangoni propulsion based on a photothermal composite of graphene and polydimethylsiloxane is reported. By combining the microfluidic channels with photothermal air chambers, a light‐triggered switch that can control the release of chemical “fuels” is proposed. Furthermore, a superhydrophobic surface is fabricated on the swimming robot by laser treatment, which reduced water resistance and promoted propulsion. On‐demand actuation and swimming route planning are realized by programming the alcohol/air segments in the releasing channels, on‐demand actuation and swimming route planning have been realized. As a proof‐of‐concept, a Marangoni swimming robot equipped with a miniature digital camera is used in an actual environment. Therefore, this study is expected to advance the practical applications of the chemical Marangoni effect in swimming robots.
TL;DR: In this article , a Modular Ionic Liquid Electrospray thruster (MILET) prototype is constructed, and a diagnostic system for thrust and mass flow rate is specially developed based on an analytical balance method.
TL;DR: In this article , a thermal management system (TMS) with integrated on-board power generation capabilities for a Mach 8 hypersonic aircraft powered by liquid hydrogen (LH2) is presented.
Abstract: This paper introduces the concept of a thermal management system (TMS) with integrated on-board power generation capabilities for a Mach 8 hypersonic aircraft powered by liquid hydrogen (LH2). This work, developed within the EU-funded STRATOFLY Project, aims to demonstrate an opportunity for facing the challenges of hypersonic flight for civil applications, mainly dealing with thermal and environmental control, as well as propellant distribution and on-board power generation, adopting a highly integrated plant characterized by a multi-functional architecture. The TMS concept described in this paper makes benefit of the connection between the propellant storage and distribution subsystems of the aircraft to exploit hydrogen vapors and liquid flow as the means to drive a thermodynamic cycle able, on one hand, to ensure engine feed and thermal control of the cabin environment, while providing, on the other hand, the necessary power for other on-board systems and utilities, especially during the operation of high-speed propulsion plants, which cannot host traditional generators. The system layout, inspired by concepts studied within precursor EU-funded projects, is detailed and modified in order to suggest an operable solution that can be installed on-board the reference aircraft, with focus on those interfaces impacting its performance requirements and integration features as part of the overall systems architecture of the plane. Analysis and modeling of the system is performed, and the main results in terms of performance along the reference mission profile are discussed.
TL;DR: In this paper , a systematic literature review is performed; 948 papers were selected to be analyzed precisely in both qualitative and quantitative approaches to provide descriptive, metadata, and BMS function analysis reports.
Abstract: The battery-powered propulsion system is introduced in the literature as a suitable solution for the CO2 emission challenge induced by aviation. However, because of design and manufacturing factors, during or after abused operational and environmental situations, Lithium-Ion battery (LIB) safety, and reliability cannot be guaranteed. Thus, an effective Battery Management System (BMS), is an essential unit in the Electric Propulsion System (EPS) of Electric Aircraft. Battery state estimation and prediction are vital to providing required safety strategies through acquiring battery data such as current, voltage, and temperature. Various methods of state estimation are practically and technically analyzed and offered in the literature including physics-based, model-based, and data-driven approaches. Among them, the recent method seems to be a novel solution to overcome the current experimental difficulties and inaccuracies. In a data-driven method, the battery is considered as a black box while a large volume of data is applied to learn the internal dynamics of the battery, using Artificial Intelligence (AI) and Machine Learning (ML) approaches. However, there are still major uncertainties and hurdles in the application and using AI in EPS due to data source scarcity, the complexity of computation, and ambiguities in the airworthiness certification process. In this study, a systematic literature review is performed; 948 papers were selected to be analyzed precisely in both qualitative and quantitative approaches to provide descriptive, metadata, and BMS function analysis reports. The goal of the research is to review BMS strategies supported by intelligent algorithms to propose appropriate solutions for battery management of EPS based on the proposed BMS necessary functions. Moreover, current airworthiness certification regulations are analyzed, and it is shown that the existing status is insufficient to satisfy critical issues for employing data-driven methods in the battery management of future electric aircraft including AI safety risk assessment and learning assurance. Finally, trends show an increase in studies on the subject of AI themes application in battery state estimation during the last ten years, especially for the State of Charge and the State of Health. However, there are still gaps in research for the application of intelligent technology in State of Function (SOF) and State of Power (SOP) estimation as one of the most imperative functions of the BMS in EA, which consists of less than 1 % of the total studies in this field.
TL;DR: In this article , a ship design for marine demonstration, integrating eco-friendly alternative fuels and electric propulsion system components, is presented, where the authors demonstrate a preparation process for the realization of marine carbon neutrality and future ship design through international joint research, standardization, and ship development.
Abstract: As the IMO aims to reduce greenhouse gas emissions from ships by more than 50% by 2050 compared to 2008, the paradigm of the shipbuilding and shipping industries is changing. The use of carbon-free fuels, such as hydrogen and ammonia, is progressing, along with the incorporation of batteries and fuel cells in ships. With the introduction of various propulsion power sources, the application of electric propulsion systems to ships is also expected to accelerate. The verification of reliability and safety is of paramount importance in the development of new technologies designed in response to environmental regulations. However, maritime demonstration is time-consuming and expensive. Therefore, an effective means of demonstrating the performance, reliability, and safety of various marine carbon-neutral technologies with a small burden is required. This study introduces a ship design for marine demonstration, integrating eco-friendly alternative fuels and electric propulsion system components. We further demonstrate a preparation process for the realization of marine carbon neutrality and future ship design through international joint research, standardization, and ship development, which can be linked to manpower training.
TL;DR: In this article , the performance and emission indexes of diesel engine and LNG engine are compared and analyzed, and the fuel cost advantage, green advantage and power performance disadvantage of LNG compared with diesel engine are determined.
Abstract: Advances in power and propulsion and energy management improvements can significantly contribute to reducing emissions. The International Maritime Organization (IMO) Marpol regulations impose increasingly stringent restrictions on ship’s emission. According to the measured data of the target ship in typical working profiles, the power fluctuation, fuel consumption and emission data are analyzed, and the result represented that there are serious fuel consumption and pollution problems in the diesel engine power system. Based on the ship-engine propeller matching design theory, the ship-engine propeller model was built, and the new propulsion system power of the target ship was obtained by simulation. From the perspectives of power, economy and green, the performance and emission indexes of diesel engine and LNG engine are compared and analyzed, and the fuel cost advantage, green advantage and power performance disadvantage of LNG engine compared with diesel engine are determined. By comparing the topological structures of different hybrid propulsion forms, the new propulsion form of the ship is improved to be the gas-electric hybrid propulsion system based on the ESS (Energy Storage System), and the selection of the supercapacitors and lithium batteries is compared. Based on the low-pass filter strategy, the power distribution of the ultracapacitor and lithium battery is distributed. In order to determine the optimal ESS configuration, a capacity configuration model with investment cost, fuel cost and energy storage life as objective functions was established. NGSA-II algorithm was used to calculate the model and scheme selection was completed based on the scheme decision model. In this case, the optimal scheme significantly reduces pollutant emissions, it also reduces daily fuel costs by 38% and the result shows that we can complete the cost recovery in 1.28 years.
TL;DR: In this article , the authors employ a data-driven approach for analyzing the blowoff phenomenon of the Hall-effect propulsion system, which is characterized by large linear and small nonlinear parameters of the stochastic Van der Pol equation.
TL;DR: In this paper , the aircraft configuration impacts of a liquid-hydrogen fuel-cell electric propulsion system when integrated into a single-aisle, transport-class aircraft having comparable performance capability of a Boeing 737-800 were investigated.
Abstract: This study considers the aircraft configuration impacts of a liquid-hydrogen fuel-cell electric propulsion system when integrated into a single-aisle, transport-class aircraft having comparable performance capability of a Boeing 737-800. This study demonstrates that, given estimated developments in future components and subsystem technologies for a 2050 entry into service date, the design of an aircraft with a liquid-hydrogen fuel-cell–based propulsion system can be feasibly achieved while still meeting mission-level performance characteristics consistent with modern commercial aircraft throughout the anticipated lifetime of the aircraft. Key technologies that enable this are the purposeful integration of fuel cell thermal management, independent inlet compression to pressurize the air input to the fuel cells, and leveraging distributed electric propulsion advantages. Exploration into the impact of fuel cell power loss due to degradation is also presented. The results show a promising configuration of a liquid-hydrogen fuel-cell–based commercial aircraft to serve as a feasible replacement of narrow-body transport aircraft to help meet climate goals set for the aviation industry.
TL;DR: In this paper , a three-thick coils system is proposed for tailoring the magnetic field in-flight in accordance with electron pressure distribution, which can contribute to the attitude control or the precision pointing of the spacecraft, the technology for removal of space debris and manipulating the ion momentum flux lost to a wall or unsteady laser produced plasma flow in a magnetic nozzle.
TL;DR: In this article , a real-time two-layer power management system (PMS) is proposed for hybrid-powered ship in order to maintain a high fuel efficiency and a healthy state-of-charge (SOC) level over the voyage even in extreme sea conditions.
Abstract: The increasing demand for improving fuel efficiency of marine transportation has presented opportunities for the development of the power management system (PMS). Different from the terrestrial power system, a shipboard power system contains a large proportion of propulsion loads, which has the characteristics of high dynamics, periodicity, uncertainty, and high dependence on the marine environment. The propulsion load fluctuation induced by sea waves, in-and-out-of water effects, and changeable consumers requirements, may lead to a low power quality and fuel efficiency and it brings challenges in the development of the marine PMS. In addition, the fluctuated load profiles could also be volatile and unpredictable, which makes long-term load forecasting unrealizable and real-time load forecasting essential. To address these issues, a real-time two-layer PMS is proposed for hybrid-powered ship in this article, that can maintain a high fuel efficiency and a healthy state-of-charge (SOC) level over the voyage even in extreme sea conditions. To adapt well to the fluctuated and changeable load condition, a novel multistep load forecasting system is integrated to make accurate load forecasting in a very very short-term time scale (centisecond). Multiple cases studies are conducted under different cases of voyage time, sailing speed, wave conditions, and submergence ratios. The results show that the proposed PMS can significantly reduce the power tracking delays, improve the fuel efficiency, and maintain a healthy SOC level.
19 Jan 2023
TL;DR: In this paper , an uncertainty quantification analysis for future hybrid-electric commercial aircraft is presented for the electrified aircraft propulsion systems of a 150-passenger hybrid electric aircraft model.
Abstract: The NASA Electrified Powertrain Flight Demonstration (EPFD) program is a collaboration between industry and academia to accelerate the development and implementation of megawatt-class power systems in commercial aviation. Technology development programs are often associated with cost, performance, and schedule risks, which can result from technical uncertainty. To assess and offer insight to effective mitigation of risks associated with the NASA EPFD program, an uncertainty quantification analysis for future hybrid-electric commercial aircraft is addressed. An uncertainty analysis is presented for the electrified aircraft propulsion systems of a 150-passenger hybrid-electric aircraft model. Uncertainty at the component-level of the powertrain system is considered and its effect is propagated to vehicle-level metrics. The primary focus is identifying and assessing the key uncertain technological inputs driving the variability of the vehicle's performance responses.