Progress in Aerospace Sciences最新文献

It has become apparent that the continued emission of greenhouse gases will lead to the onset of irreversible climate change, thereby endangering human civilization on our planet. Although the aviation sector of the global economy contributes only a small percentage of the total emissions the transition to emission-free (green) aviation will be a crucial part of the transition to a green global economy by mid-century if a catastrophe is to be averted. It is unfortunate that the danger posed by climate change is not yet regarded as an emergency that requires an “all hands on deck” global effort. This lack of awareness is exacerbated by the widespread view that the task is too immense to be accomplished in this century. It is our view that the past aerospace engineering successes and failures provide us with the lessons needed to convince the aerospace engineering community that the transition to green aviation can indeed be accomplished if economic and special interest considerations are set aside.

The sustainability of air transport is increasingly studied in relation to climate issues. The objective of this paper is to provide the key elements for assessing whether a given transition scenario for aviation could be considered as sustainable in the context of the Paris Agreement. Addressing this question relies on a broad range of concepts which are reviewed. First, ethical considerations related to effort-sharing mitigation principles and physical considerations on climate impacts of aviation are introduced. Then, the technological levers of action for mitigating CO₂ and non-CO₂ effects are detailed. Concerning CO₂ emissions, low-carbon alternative energy carriers represent the main lever, with a wide range of solutions with varying degrees of maturity and decarbonization potentials. Other significant CO₂ levers include improving aircraft architecture efficiency and accelerating fleet renewal. Concerning non-CO₂ effects, contrail effect mitigation through operational strategies is one of the most promising lever. Aviation transition scenarios are then reviewed, with a particular focus on scenario simulation and sustainability assessment methodologies. Prospective scenarios are a useful framework for assessing the impacts of technological levers on the achievement of climate objectives. This review leads to the conclusion that technological levers have an important role to play in making aviation sustainable; however, significant uncertainties weigh on their feasibility, particularly for the most ambitious scenarios which rely on strong technological and political trade-off assumptions. The paper ends by raising the question about the meaning of sustainable aviation, which must be based on technological but also, for instance, social, economic and ethical considerations.

With the lunar base, crewed Mars exploration and other future exploration plans proposed, the thermal control system of spacecraft will face challenges such as significantly higher thermal load and more complex and variable thermal environment. Traditional radiant heat sinks can hardly cope with the more demanding heat rejection requirements brought by these challenges, and more efficient, reliable and robust heat sinks are urgently needed to ensure the smooth running of future exploration programs. The sublimation or evaporation cooling technology has great potential to respond to these potential thermal control challenges. They utilize the latent heat of phase change from sublimation or evaporation of the consumable working medium into the space environment to reject the waste heat generated by the crew or equipment inside the spacecraft. This paper presents a review of the research progress in recent decades around two typical consumable heat sinks, the water sublimator and the water membrane evaporator. It mainly covers the basic issues and recent advances in component configuration, analytical and computational methods, experimental research methods, and system application architecture. The remaining problems and potential solutions in the development of water sublimator and water membrane evaporator as well as the direction of future development are summarized and pointed out.

There have been growing research interests in high-order discontinuous schemes over recent years. With established theoretical basis and framework, more efforts have recently been taken to enable discontinuous-scheme capabilities for modeling complex multi-physical flows. Substantial achievements and milestones have been reached in the development of compatible numerical methods and algorithms that leverage high-order discontinuous schemes. The objective of this study is to comprehensively survey and summarize the key algorithmic components relevant to discontinuous schemes, while identifying the current state of the art in their capabilities for modeling multiphase and multicomponent flows. Furthermore, this review examines representative applications from recent literature to showcase the promising performance of discontinuous schemes in various scenarios. The review also identifies the limitations and bottlenecks encountered in previous research efforts and offers recommendations for future investigations. The primary aim of this review is to serve as a valuable guidebook for researchers in the field, facilitating the development of new computational fluid dynamics (CFD) capabilities based on discontinuous schemes.

Space–time scale-resolved diagnostic and computational campaigns routinely produce high-fidelity multi-disciplinary truth-model quality datasets for complex configurations. The extraction of the primary features of engineering or scientific interest and modeling of potential low-rank dynamics has proven challenging because of the massive sizes of the databases. One approach to overcome these challenges has been through system identification based decomposition techniques. In the present work, we build on comprehensive reviews on the subject by elucidating recent advances and applications for aerodynamic flow problems. Through a succinct but panoramic treatment exemplified with relevant applications, we expect to inform the reader of method capabilities in a manner that can guide selection strategies promising critical insights into complex fluid dynamics problems. The methods are broadly classified into modal-based and physics-based. Major advances in the former are extensions of the linear framework to non-homogeneous flowfields and Floquet analysis of secondary instability, applicable to broad ranges of complexity in basic states and speed regimes. Forced response analysis has aided our understanding of non-modal instability mechanisms which extend in some ways analogous to those in the global stability literature; applications to three-dimensional flows and operator-free concepts have been particularly illustrative. Advances in modal techniques for nonlinear flowfields have sharpened focus on prescribed spectral and interaction characteristics, expanded applicability to large-scale databases through streaming approaches, and integrated multi-physics into analyzed data. Physics-based techniques, motivated by the fundamental splitting theorem of Kovasznay, have proven particularly valuable in educing mechanisms sustaining multi-modal dynamics with unique physical aspects. Helmholtz decomposition combined with signal processing procedures have provided insights into the behavior of wall-bounded and free-shear turbulence, emphasizing the effects of compressibility on energy dynamics, coherent structures, and acoustics. The generalization of physics-based eduction techniques using momentum potential theory has improved our understanding of aeroacoustics of a broad class of flowfields, and further provided direction for flow control of shear-layer noise and hypersonic boundary layer dynamics.

The development of advanced military aero-engines with high thrust-to-weight ratios requires high-temperature-rise (HTR) technology for core component combustors. This poses a major challenge to multidisciplinary design and optimization of combustors. This paper analyzes the technical characteristics of the HTR combustor and summarizes and proposes three current major technical challenges. For each technical challenge, systematic analysis and comprehensive discussion are conducted from the aspects of technical strategies and research progress. The three technologies reviewed in this paper include (1) combustion configuration technology, (2) liner thermal protection technology involving advanced liner cooling and ceramic matrix composite (CMC) liners, and (3) outlet distribution control technology. We also present our insights regarding current solutions and future research trends related to the three major technical limitations of the HTR combustor.

Pogo is a longitudinal vibration of liquid rockets, which is considered as a fluid-structure coupling of liquid supply system and rocket's structure. Its suppression is a critical element in the design of the fluid piping systems in liquid rockets, for many of them have been reported suffering the pogo vibration worldwide. Pogo suppression is a systematic technology including fluid-structure modelling, stability analysis and suppression devices. The suppression methods for pogo attracted much attention in the 1960s–1980s, while rare review can be found in recent decades. This article is to review pogo suppression methods vastly, and find effective and potential approaches for the future. The research and experience on the suppression technologies of pogo are investigated comprehensively, including the passive and active schemes. The advantages and limitations of various methods are discussed carefully, which indicates that the suppression is a systematic consideration. Moreover, the progress of the active control of fluid pulsation in hydraulic systems is also introduced detailedly, expecting a combination with the pogo application.

In recent years, there has been a growing need for vehicles with air-water amphibious capacities for both military and civil applications, and the technological advances in unmanned systems make it more feasible to create such vehicles. As a result, the hybrid aquatic-aerial vehicle (HAAV), which integrates the locomotion capacity of aerial vehicles and underwater vehicles, is facing a vast developing opportunity, and plenty of related technologies have emerged. However, no current HAAV has simultaneously achieved the operational capacities of UUVs and UAVs in their moving domain without sacrificing performance. The exploitation of HAAVs is still facing several significant challenges, such as insufficient water-air compatibility, inefficient water-entry locomotion, and inefficient water-exit locomotion. The development trend of HAAVs could be more transparent, with the proposed technologies and design concepts being sorted out clearly. Therefore, a literature review of this novel vehicle is urgently in demand. We build this review on our previous survey published in 2015, which is regarded as the earliest review on HAAVs. In this paper, we put forward a novel systematic classification method of the fully functional HAAVs by considering the structure configurations and introduce the prototype development of each kind. Then, the research statuses of the drive solutions and trans-media solutions are analyzed respectively. After that, we analyze the demands of HAAVs both in the military and civil applications and evaluate the device performances of the various HAAVs. Furthermore, the applicability of each category is eventually obtained by comparing their device performances with the application demands of various applications. Finally, the challenges of water-air compatibility, water-entry locomotion, and water-exit locomotion are discussed. Moreover, the key technologies to overcome them, i.e., morphing blade techniques, morphing wing techniques, variable density techniques, structural buffer techniques, bionic water-entry techniques, surface dehydration techniques, and bionic water-exit techniques are analyzed. The research in this paper will provide more promising solutions for aquatic-aerial locomotion and inspire more practical studies in the HAAV field.

Flexibility and lightweight are promising research topics for space science and technology, which benefit to reduce load, reduce volume, and integrate device. However, most photoelectronic devices on spacecraft are rigid devices now, because the space environment consists of irradiations and thermal cycling, with higher requirements for flexible photoelectronic materials and devices. The main bottlenecks include: the synthesis of space-durable packaging materials, the fabrication and packaging of flexible photoelectronic devices, and the effective investigation method for irradiation mechanism analysis. In view of these problems, this review presents the synthesis of bulk-phase silicon-reinforced yellow and transparent polyimides with space durability, the optical modulation of bulk-phase silicon-reinforced polyimide to ultra-black film and flexible color filters, the electrical modulation of bulk-phase silicon-reinforced polyimide into flexible transparent electrode, the integration of the bulk-phase silicon-reinforced transparent polyimide and flexible triple-junction GaAs thin-film solar cell, and the exploration of general investigation methods for irradiation mechanism based on the penetration depth and damage modes including atomic oxygen, ultraviolet, electron, proton, and thermal cycling. The material synthesis, device fabrication, and mechanism analysis method focus on the core scientific problems of space-durable flexible lightweight photoelectronic materials and devices, leading the development direction of flexible and lightweight space science and technology.