Showing papers on "Propulsion published in 2020"

Electric Power Systems in More and All Electric Aircraft: A Review

Abstract: Narrow body and wide body aircraft are responsible for more than 75% of aviation greenhouse gas (GHG) emission and aviation, itself, was responsible for about 2.5% of all GHG emissions in the United States in 2018. This situation becomes worse when considering a 4-5% annual growth in air travel. Electrified aircraft is clearly a promising solution to combat the GHG challenge; thus, the trend is to eliminate all but electrical forms of energy in aircraft power distribution systems. However, electrification adds tremendously to the complexity of aircraft electric power systems (EPS), which is dramatically changing in our journey from conventional aircraft to more electric aircraft (MEA) and all electric aircraft (AEA). In this article, we provide an in-depth discussion on MEA/AEA EPS: electric propulsion, distributed propulsion systems (DPS), EPS voltage levels, power supplies, and EPS architectures are discussed. Publications on power flow (PF) analysis and management of EPS are reviewed, and an initial schematic of a potential aircraft EPS with electric propulsion is proposed. In this regard, we also briefly review the components required for MEA/AEA EPS, including power electronics (PE) converters, electric machines, electrochemical energy units, circuit breakers (CBs), and wiring harness. A comprehensive review of each of the components mentioned above or other topics except for those related to steady state power flow in MEA/AEA EPS is out of this article's scope and should be found somewhere else. At the close of the paper, some challenges in the path towards AEA are presented. Unless the discussed challenges are satisfactorily addressed and solved, arriving at an AEA that can properly operate over commercial missions will not be possible.

Perspectives, frontiers, and new horizons for plasma-based space electric propulsion

Abstract: There are a number of pressing problems mankind is facing today that could, at least in part, be resolved by space systems. These include capabilities for fast and far-reaching telecommunication, surveying of resources and climate, and sustaining global information networks, to name but a few. Not surprisingly, increasing efforts are now devoted to building a strong near-Earth satellite infrastructure, with plans to extend the sphere of active life to orbital space and, later, to the Moon and Mars if not further. The realization of these aspirations demands novel and more efficient means of propulsion. At present, it is not only the heavy launch systems that are fully reliant on thermodynamic principles for propulsion. Satellites and spacecraft still widely use gas-based thrusters or chemical engines as their primary means of propulsion. Nonetheless, similar to other transportation systems where the use of electrical platforms has expanded rapidly, space propulsion technologies are also experiencing a shift toward electric thrusters that do not feature the many limitations intrinsic to the thermodynamic systems. Most importantly, electric and plasma thrusters have a theoretical capacity to deliver virtually any impulse, the latter being ultimately limited by the speed of light. Rapid progress in the field driven by consolidated efforts from industry and academia has brought all-electric space systems closer to reality, yet there are still obstacles that need addressing before we can take full advantage of this promising family of propulsion technologies. In this paper, we briefly outline the most recent successes in the development of plasma-based space propulsion systems and present our view of future trends, opportunities, and challenges in this rapidly growing field.

Energy efficiency of integrated electric propulsion for ships – A review

Abstract: There has been mounting concerns over energy consumption and environmental impacts due to an increase in worldwide shipping activities. The International Maritime Organization has adopted regulations to impose limits on greenhouse gas emissions originated from fuel combustion of marine vessels. Such regulations are introduced in terms of energy efficiency design index and energy efficiency operational indicator. Extensive electrification of ship propulsion and shipboard power systems has been vastly proposed in the literature to make onboard energy systems more efficient. However, energy efficiency in the context of maritime transport is becoming even more stringent. Various technologies and operational practices therefore are being proposed to ensure full compliance with the tightening restrictions. The methods to increase energy efficiency and environmental performance of all-electric ships to satisfy such requirements involve integration of energy storage with a contribution of intelligent power management to optimize power split between various power generation sources; a tendency toward DC power distribution due to eliminating the need of all generators to be synchronized at a specific frequency; installation of unconventional propulsors for greater maneuverability requirements while keeping fuel consumption low; adoption of low carbon content fuel like liquefied natural gas for dual fuel diesel electric propulsion; establishment of onboard renewable energy systems for alternative clean power options; fuel cell integration in complementary operation with conventional diesel generators. This paper identifies promising technologies and practices that are applicable to onboard energy systems of all-electric ships and also reveals energy efficiency sensitivity of all-electric ships to different applications. The proposed strategies should be eventually combined with alternative technology-based and operational-based measures as implemented on conventional propulsion ships in order to realize full potential for energy efficient operation.

A review of concepts, benefits, and challenges for future electrical propulsion-based aircraft

Abstract: Electrification of the propulsion system has opened the door to a new paradigm of propulsion system configurations and novel aircraft designs, which was never envisioned before. Despite lofty promises, the concept must overcome the design and sizing challenges to make it realizable. A suitable modeling framework is desired in order to explore the design space at the conceptual level. A greater investment in enabling technologies, and infrastructural developments, is expected to facilitate its successful application in the market. In this review paper, several scholarly articles were surveyed to get an insight into the current landscape of research endeavors and the formulated derivations related to electric aircraft developments. The barriers and the needed future technological development paths are discussed. The paper also includes detailed assessments of the implications and other needs pertaining to future technology, regulation, certification, and infrastructure developments, in order to make the next generation electric aircraft operation commercially worthy.

Making the Case for Switched Reluctance Motors for Propulsion Applications

Abstract: This paper makes the case that Switched Reluctance Motor (SRM) is an exceptionally attractive technology to respond to the increasing demand in propulsion applications for high-efficiency, high-performance, and low-cost motors with a more secure supply chain. The paper also presents methods to effectively reduce torque ripple and acoustic noise, which have been the major issues impeding the widespread use of SRMs. Finally, SRM designs for two propulsion motors, one for an e-bike and the other for a hybrid electric vehicle application, are presented which have been proposed to replace permanent magnet machines.

Study of braking energy recovery impact on cost-efficiency and environmental safety of vehicle

Abstract: The article addresses the evaluation of the impact of regenerative braking on fuel consumption and, consequently, on pollutant emissions from vehicles operated under conditions leading to frequent acceleration and deceleration. We assume that the vehicle is equipped with a system of conversion and accumulation of electric energy obtained only from braking. Basic analyzed characteristics are determined by a comparison of gasoline engine operation modes with braking energy recovery and without it. As initial physicomathematical tools, we use relationships of propulsion power and energy analysis and propulsion drive operation, which were previously suggested by one of the authors. As an example of using the mentioned relationships, the article presents the analysis results for a vehicle moving in the low-speed segment of the WLTC driving cycle. Energy passing through the battery and energy reserve in it are calculated. It is assumed that the accumulated braking energy makes it possible to start moving at the next segment not using the gasoline engine; the engine starts its operation only after the energy in the battery is exhausted. Superposition of the curves of gasoline engine operation modes with and without recovery allows us to estimate changes in the energy generated. In order to account for different values of specific fuel consumption, the authors use an adjustment factor, which takes into account pollutant emissions from the vehicle depending on the average speed. Functions of changes in fuel consumption and pollutant emissions when using regenerative braking are obtained by the integration of values. The authors compare the obtained results with the results of road tests of vehicles with the energy recovery system. The materials suggested expand our knowledge of the operational properties of vehicles with electromechanical and electrical power units

Recent Progress, Development Trends, and Consideration of Continuous Detonation Engines

Abstract: The continuous detonation engine (CDE) is based on detonation waves and is a new jet engine concept that is expected to bring a technical revolution to current aviation and aerospace propulsion sys...

Ion thrusters for electric propulsion: Scientific issues developing a niche technology into a game changer.

Abstract: The transition from old space to new space along with increasing commercialization has a major impact on space flight, in general, and on electric propulsion (EP) by ion thrusters, in particular Ion thrusters are nowadays used as primary propulsion systems in space This article describes how these changes related to new space affect various aspects that are important for the development of EP systems Starting with a historical overview of the development of space flight and of the technology of EP systems, a number of important missions with EP and the underlying technologies are presented The focus of our discussion is the technology of the radio frequency ion thruster as a prominent member of the gridded ion engine family Based on this discussion, we give an overview of important research topics such as the search for alternative propellants, the development of reliable neutralizer concepts based on novel insert materials, as well as promising neutralizer-free propulsion concepts In addition, aspects of thruster modeling and requirements for test facilities are discussed Furthermore, we address aspects of space electronics with regard to the development of highly efficient electronic components as well as aspects of electromagnetic compatibility and radiation hardness This article concludes with a presentation of the interaction of EP systems with the spacecraft

Initial Sizing Methodology for Hybrid-Electric General Aviation Aircraft

Abstract: Electric and hybrid-electric propulsion offer unique possibilities to improve aircraft efficiency and performance. The potential advantages are fuel savings, lower emissions, and reduced noise. Bec...

A holistic system approach for short range passenger aircraft with cryogenic propulsion system

Abstract: Currently, hybrid-electric aircraft are under investigation as one possible solution to reduce the emissions of the aviation industry according to Flightpath 2050 of the European Union. To meet the drive trainʼs requirements on low mass while aiming for highest efficiency, superconducting technologies are regarded as a key enabling technology for drive train powers of several tens of megawatts. Within the German nationally funded project TELOS an exemplary mission profile and the physical measures of a 220-passenger aircraft are used to derive the requirements for a cryogenic-cooled serial hybrid-electric propulsion system. To optimize the total system performance, we subsequently evaluated the superconducting and cryogenic-cooled components by using computationally fast, analytical models. This approach allows quantifying the system performance by using component technologies being available today. In particular, the system performance of geared drive to direct drive propulsion units are compared and the influence of the DC bus voltage and the electric frequencies of the AC circuits on the mass and the efficiency of the drive trains are analysed.

Underwater Bioinspired Propulsion: From Inspection to Manipulation

Abstract: This article presents the design of a biomimetic underwater vehicle-manipulator system (BUVMS) with bioinspired long-fin propulsion and its control methods. The kinematic analysis of bioinspired long-fin propulsion is conducted, and the maximum thrust of this propulsion derived from our thrust measurement platform can be up to 25 N. Bioinspired long-fin propulsion is introduced to construct the BUVMS for inspection and manipulation tasks, and the system architecture of the BUVMS is described. Moreover, real-time dynamic dubins-helix path planning and tracking of the biomimetic vehicle are proposed to realize the arrival of the desired pose. The tracking error is less than 0.23 body length. Finally, coordinated control between the biomimetic vehicle and the manipulator is developed to achieve autonomous manipulation. The reaction of the manipulator served as feedforward compensation is added into the closed-loop control of the biomimetic vehicle. The experimental results are provided to illustrate the validity of the proposed methods.

Ship energy performance study of three wind-assisted ship propulsion technologies including a parametric study of the Flettner rotor technology

Abstract: A 4 degrees of freedom ship performance prediction model is used to compare wind-assisted ship propulsion technologies: the Flettner rotor, a wingsail and the DynaRig concept. An Aframax Oil Tanker...

Development and Motion Control of Biomimetic Underwater Robots: A Survey

Abstract: Biomimetic underwater robots have attracted considerable research attention globally, owing to their quieter actuations, higher propulsion efficiency, and stronger maneuverability when compared with conventional underwater vehicles equipped with axial propellers. This article provides a comprehensive survey of current research in this field. First, we review the development status of biomimetic underwater robots in both body/caudal fin (BCF), median/paired fin (MPF), and their hybrid propulsion modes. Then, we outline the motion control methods employed in biomimetic underwater robots, including open-loop swimming control and typical closed-loop control strategies. In particular, we detail our latest studies on the RobCutt series underwater robots. On this basis, some critical issues and future directions are summarized. We predict that biomimetic underwater robots will have excellent prospects in underwater environment exploration and resource utilization.

Multiphase PMSM With Asymmetric Windings for More Electric Aircraft

Abstract: This article presents a multiphase permanent magnet synchronous motor (PMSM) for the more electric aircraft propulsion. The stator winding of the motor is composed of multiple sets of multiphase windings with different parameters. The purpose of the motor design is to modify the distribution of the high-efficiency area of the motor by reasonably matching the winding parameters of each set, thereby making the motor more suitable for the working condition of more electric aircraft and improving the working efficiency of the motor. This article analyzes the selection principle of slot–pole combination and the influence that asymmetric windings have on the motor magnetic field. Three basic matching modes are proposed: equal torque matching, equal power matching, and equal speed matching. The motor model is established, with the external characteristics, efficiency, and dynamic response of different matching modes being compared and analyzed. The results show that equal torque matching and equal speed matching can reduce the total loss of the motor in a complete flight working condition, whereas equal power matching is not suitable for more electric aircraft.

Fuel consumption and emissions of ocean-going cargo ship with hybrid propulsion and different fuels over voyage

Abstract: Hybrid propulsion and using liquefied natural gas (LNG) as the alternative fuel have been applied on automobiles and some small ships, but research investigating the fuel consumption and emissions over the total voyage of ocean-going cargo ships with a hybrid propulsion and different fuels is limited. This paper tries to fill the knowledge gap by investigating the influence of the ship mission profile, propulsion modes and effects of different fuels on the fuel consumption and emissions of the ship over the whole voyage, including transit in open sea and manoeuvring in close-to-port areas. Results show that propulsion control and electric power generation modes have a notable influence on the ship's fuel consumption and emissions during the voyage. During close-to-port manoeuvres, propelling the ship in power-take-in (PTI) mode and generating the electric power by auxiliary engines rather than the main engine will reduce the local NOx and HC (hydrocarbons) emissions significantly. Sailing the ship on LNG will reduce the fuel consumption, CO2 and NOx emissions notably while producing higher HC emissions than traditional fuels. The hybridisation of the ship propulsion and using LNG together with ship voyage optimisation, considering the ship mission, ship operations and sea conditions, will improve the ship's fuel consumption and emissions over the whole voyage significantly.

Analysis of the Detonation Wave Structure in a Linearized Rotating Detonation Engine

Abstract: The rotating detonation engine is increasingly favored as a viable pressure gain combustion technology for both propulsion and power generation applications. Practical designs involve the discrete ...

Propulsion Performance of Cylindrical Rotating Detonation Engine

Abstract: This study evaluated the propulsion performance of a nozzleless, cylindrical rotating detonation engine (RDE). Using a C2H4–O2 mixture, the RDE was tested in a low-back-pressure environment at prop...

A Review of Electrical Motor Topologies for Aircraft Propulsion

Abstract: This paper provides a review of the state-of-the-art in aircraft electrical propulsion (AEP). Initially, the limitations of on-board energy storage devices are highlighted and contextualised. The definitions of useful measures for determining the suitability of motor design, namely specific power and motor torque per unit rotor volume (TRW), are discussed and relevant examples are provided. The classifications of motors used for terrestrial vehicle applications are reviewed and their limitations highlighted regarding their suitability to AEP applications. A discussion on motor configurations for aerospace applications is provided which includes: synchronous motor stator winding configurations; axial flux motor configurations and the causes of energy losses. Additionally, the topologies and performance characteristics of existing aerospace motor technologies are examined. It was concluded that electrical motors provide an ideal means for achieving aircraft propulsion and that higher motor speeds are likely to be required for future commercial aircraft motor designs.

Superconducting motors for aircraft propulsion: the Advanced Superconducting Motor Experimental Demonstrator project

Abstract: The European Union-funded Advanced Superconducting Motor Experimental Demonstrator (ASuMED) project started in May 2017 with the purpose of demonstrating the benefits of a new, fully superconducting motor for reaching the targets established by the Flightpath 2050 plan. The project aims at a motor power density of 20kW kg$^{-1}$ using a high-temperature superconducting (HTS) stator. The rotor will use HTS stacks operating like permanent magnets. A highly efficient cryostat for the motor combined with an integrated cryogenic cooling system and associated power converter will be used. This article provides a general overview of the prototype that is currently being assembled and that will be tested soon.

Hydrogen Fuel Cells for Ship Electric Propulsion: Moving Toward Greener Ships

Abstract: This article addresses several challenges related to the development of zeroemission ship propulsion through hydrogen fuel cells (FCs) as the main source of energy. One main barrier to the development of FC propulsion is the production and transportation of hydrogen. However, in this article, it is assumed that hydrogen is available in the form of pure hydrogen or hydrocarbons. Still, many challenges related to the installation and operation of the FC remain; we discuss some of the main issues, such as the technical requirements for FC installation onboard, power system integration, control, and safety and related regulations. The factors addressed in this article are limited to the tools, requirements, and components that are physically located onboard ships.