The future and technique challenges of high-speed ground effect vehicle enrolled in maritime transportation

This paper presents a high-speed ground effect vehicle(HS-GEV)used specifically for maritime transportation.Given the limitations of current vessels,including various types of watercraft and high-speed boats,in fulfilling of needs in different maritime transportation scenarios,the HS-GEV emerges as a promising solution to address unmet requirements.To efficiently accomplish maritime transportation missions with quickness and safety,several critical features are emphasized,including short take-off on water,flight maneuverability and flight stability.The key techniques required to achieve these features,as well as recent progress highlights,are introduced.Following and promoting these crucial techniques is also suggested as a future step to improve HS-GEV performance.With its predominant features,the HS-GEV holds immense application value in enhancing a high-speed maritime transportation system that aligns with the evolving needs of the real world.

Review of prevention and mitigation technologies for thermal runaway in lithium-ion batteries

Lithium-ion batteries have been widely used in transportation,power equipment,aerospace,and other fields.However,the complex electrochemical reactions inside the battery cause excessive heat generation rate due to thermal,mechanical,and electrical abuse conditions,and even lead to thermal runaway.The problem of thermal runaway has become an important factor limiting its use.This review summarizes the intrinsic safety of batteries,thermal management,early monitoring and warning for thermal runaway,fire prevention and fire suppression technologies.The intrinsic safety technologies were summarized from the aspects of electrolyte flame retardancy,improvement of thermal stability of battery materials,and ceramic separators.To effectively control battery temperature,thermal management technologies were elaborated from the perspectives of air cooling,liquid cooling,heat pipes,phase change materials,and coupled thermal management.Single parameter detection,multi parameter composite detection,and new detection technologies were also discussed.In-situ monitoring of batteries based on fiber optic sensors helps to achieve early warning of thermal runaway.After thermal runaway occurs,fire prevention and fire extinguishing technology can effectively reduce the harm of thermal runaway,which should be given sufficient attention.This work provides important references value and research ideas for the prevention and mitigation of thermal runaway in lithium-ion batteries.

Investigation on the characteristics and mechanism of AZ80A magnesium alloy corrosion by Halon 1301 and CF_(3)I

In order to study the application of gas fire extinguishing agents in civil aircraft fire extinguishing systems,the corrosion characteristics and mechanisms of Halon 1301 and CF3I on AZ80A magnesium alloy were comparatively analyzed.The experimental methods combined with density functional theory were applied to explore the corrosion mechanism.The results indicate that Halon 1301 and CF3I exhibit good compatibility with AZ80A magnesium alloy through physical adsorption at room temperature and pressure,where Halon 1301 has a more stable adsorption configuration.However,with increasing temperature,pyrolysis reactions occur leading to the formation of fluorine containing corrosive substances which can react with magnesium alloy to generate the corrosion production of MgF2 and coke.Although MgF2 and coke can partically reduce reaction rates and protect against corrosion,the presence of MgF2 promotes further pyrolysis,generating more corrosion products.Consequently,the accumulation of corrosion products leads to a loss of metallic luster and a decline in mechanical properties of magnesium alloy along with interfacial cracking due to mutual extrusion between MgF2 and carbon deposition layers.These studies offer theoretical guidance for utilizing CF3I in civil aircraft fire extinguishing systems while facilitating rapid screening for efficient clean gas extinguishing agents.

A review on ignition characteristics of arc faults in wire system of aircraft

The development of aircraft electrification can improve energy utilization efficiency and reduce the green gas emissions,which is the future trend.However,aircraft electrification would increase the probability of arc faults in the wire system.Arc can ignite the combustibles by the arc column or hot droplets,which has high fire risks.Arc faults have triggered several catastrophic aeronautical accidents in the past.Electrical fire safety is a top priority of aircraft in the future.An in-depth understanding of the arc fault ignition mechanism plays a crucial role in preventing arc fires and optimizing wire layout.This review article performs a comprehensive summary of relevant research concerning the fire risks of arc faults,the causes of arc faults in the wire system,and the ignition behaviors of arc faults.The main findings regarding the direct ignition of arc faults and ignition of hot droplets are emphasized.The arc ignition characteristics in existing research are firstly summarized,including the arc ignition experiment platforms and thermal hazard characteristics of arc faults.Additionally,the generation,impacting process,and ignition characteristics of hot droplets are then presented.Finally,the limitations in existing research about ignition characteristics of arc faults are also outlined,while identifying the future research needs of fires caused by arc faults.

A study on basic research priorities and development suggestions for the digital transformation of air traffic management

Air traffic is exhibiting the characteristics of high density,high volume,and unmanned operations.To ensure smooth,efficient,safe,and reliable operations,it is necessary to promote the digital transformation of Air Traffic Management(ATM)with digitalization,autonomy,and collaboration as its typical features.This article,based on the background of current and foreseeable future ATM needs,deeply analyzes the challenges and opportunities faced by traditional ATM.It explores and proposes to further investigate the commonalities,characteristics,and evolution of air traffic,the interaction mechanism of"human-machine-environment"in air traffic,the integrated design of airborne avionics and ATM systems,the comprehensive integration of ATM based on vulnerability analysis,airspace classification management,air traffic flow management,key technologies of"perception-collision avoidance",wake vortex monitoring and interval reduction,unmanned aerial vehicle management,and the expansion of ATM capabilities in the"high frontier".The research suggests strengthening top-level planning,building an open,mutually beneficial,and win-win digital ATM ecological framework based on multi-party collaboration,coordinating the research and application of new digital ATM technologies,accelerating the occupation of the new track of low-altitude economy,and enhancing ATM capabilities driven by the digital transformation of ATM.

Enhancing air traffic operational efficiency by reducing network scale

The growing demand for air travel has led to the saturation of air traffic networks.Conventional methods of adding routes to alleviate congestion and reduce delays may not achieve the desired effect and even degrade system performance.In this paper,we explore the application of Braess’s Paradox in the reduction of air traffic networks.This counterintuitive phenomenon shows that adding new connections to a network can actually increase the overall network pressure.This study uses Hidden Markov methods and the Viterbi algorithm to match air traffic flow with routes,a machine learning approach and a mathematical method to construct cost functions for flight time and traffic volume,and finally uses genetic algorithm and the A*algorithm to detect Braess’s Paradox edges.We uses ADS-B data from the busy month of July 2019 for a case study of the air traffic network over the UK airspace.The results show that Braess’s Paradox is also applicable to multi-flight level air route networks.Removing such network edges can improve system performance.In one day’s case,the total flight time of the day’s traffic volume decreased from 11509.24 minutes to 10459.97 minutes.This equates to an average savings of 4.99 minutes of flight time per flight,which is significant in controlling delay performance.

Airworthiness engineering and practices of COMAC C919 airplane

This paper systematically summarizes the basic philosophy and principles of airworthiness that COMAC follows in the process of developing C919 large passenger aircraft.It carries out type certification along with the aircraft development process,and plans and implements compliance activities for airplane design features.Targeting the airworthiness requirements,COMAC has also established an airworthiness management system,including design assurance system and continuing airworthiness system,to ensure that aircraft are designed in accordance with airworthiness requirements,to show compliance with airworthiness requirements and to continuously ensure the airworthiness of airplane by dealing with continuing airworthiness events in service.