The promise of fuel cell-based automobiles

Fuel cell-based automobiles have gained attention in the last few years due to growing public concern about urban air pollution and consequent environmental problems. From an analysis of the power and energy requirements of a modern car, it is estimated that a base sustainable power ofca. 50 kW supplemented with short bursts up to 80 kW will suffice in most driving requirements. The energy demand depends greatly on driving characteristics but under normal usage is expected to be 200 Wh/km. The advantages and disadvantages of candidate fuel-cell systems and various fuels are considered together with the issue of whether the fuel should be converted directly in the fuel cell or should be reformed to hydrogen onboard the vehicle. For fuel cell vehicles to compete successfully with conventional internal-combustion engine vehicles, it appears that direct conversion fuel cells using probably hydrogen, but possibly methanol, are the only realistic contenders for road transportation applications. Among the available fuel cell technologies, polymer-electrolyte fuel cells directly fueled with hydrogen appear to be the best option for powering fuel cell vehicles as there is every prospect that these will exceed the performance of the internal-combustion engine vehicles but for their first cost. A target cost of $ 50/kW would be mandatory to make polymer-electrolyte fuel cells competitive with the internal combustion engines and can only be achieved with design changes that would substantially reduce the quantity of materials used. At present, prominent car manufacturers are deploying important research and development efforts to develop fuel cell vehicles and are projecting to start production by 2005.     

Materials,technological status,and fundamentals of PEM fuel cells – A review

PEM (Polymer Electrolyte Membrane) fuel cells have the potential to reduce our energy use, pollutant emissions, and dependence on fossil fuels. In the past decade, significant advances have been achieved for commercializing the technology. For example, several PEM fuel cell buses are currently rated at the technical readiness stage of full-scale validation in realistic driving environments and have met or closely met the ultimate 25,000-h target set by the U.S. Department of Energy. So far, Toyota has sold more than 4000 Mirai PEM fuel cell vehicles (FCVs). Over 30 hydrogen gas stations are being operated throughout the U.S. and over 60 in Germany. In this review, we cover the material, design, fundamental, and manufacturing aspects of PEM fuel cells with a focus on the portable, automobile, airplane, and space applications that require careful consideration in system design and materials. The technological status and challenges faced by PEM fuel cells toward their commercialization in these applications are described and explained. Fundamental issues that are key to fuel cell design, operational control, and material development, such as water and thermal management, dynamic operation, cold start, channel two-phase flow, and low-humidity operation, are discussed. Fuels and fuel tanks pertinent to PEM fuel cells are briefly evaluated.The objective of this review is three fold: (1) to present the latest status of PEM fuel cell technology development and applications in the portable and transportation power through an overview of the state of the art and most recent technological advances; (2) to describe materials and water/thermal transport management for fuel cell design and operational control; and (3) to outline major challenges in the technology development and the needs for fundamental research for the near future and prior to fuel cell world-wide deployment.     

可再生能源在空调制冷中的应用

针对目前压缩式制冷技术带来的能源短缺和环境污染问题，介绍了几种可再生能源在空调制冷中的应用技术，如地道风供冷、地源热泵系统、太阳能空调制冷，分析了可再生能源用于空调制冷的特点及发展现状，并对其应用前景做了展望。     

某国际机场飞机地面空调机组的研制及其关键技术

以电能为动力的外接式空调机组代替飞机自带的以消耗航空燃油为动力的APU装置,可以降低飞机的运行成本,同时可以改善机场环境。本文阐述飞机外接式空调机组在结构、系统和控制等方面所采用的关键技术,并将这些技术应用于研制飞机地面空调机组,经试制和测试发现,该机组降温速度快、送风温度稳定、安全可靠,能够达到替代机载APU的要求,并将其成功应用于某国际机场。     

低温工程领域的新机遇

简要介绍和讨论了低温工程领域3个令人兴奋的进展。首先描述了提高电-燃气轮机混合驱动飞机性能的两个机会:采用超导电机或定子实现超过30kW/kg的推重比,或者使用含液化天然气的混合燃料。第二个机遇是基于氢燃料电池汽车,扼要给出了氢燃料电池汽车在商业部门的快速发展情况,液氢的供应和运输是氢燃料电池汽车相关基础设施的重要组成部分。第三探讨了小型等离子体热核反应装置的新兴发展情况,等离子体热核反应将在未来10到15年成为人类重要的清洁能源来源。由于小型等离子体热核反应装置依赖于工作在超高磁场强度的高温超导磁体,所以它将为低温工程领域带来一系列创新的机会。     

等效飞行航迹在民用飞机噪声适航审定中的运用

民用飞机的噪声适航审定需要多次重复的飞行试验,飞机每次的起降都会消耗大量的燃油、产生巨大的噪声。为了降低适航审定成本,减少噪声对机场周围环境的影响,基于中国民航局航空器型号和适航合格审定噪声规定,对某型飞机的起飞和进近噪声数据和起飞降落程序进行分析,得到适航规定接受的等效飞行程序和等效飞行航迹。等效飞行航迹的得出和使用,既降低了国产大飞机在适航审定过程中的适航成本和噪声污染,又为工程技术人员在新型飞机的噪声适航审定过程中提供了一种可参考的办法。     

Modeling: driving fuel cells

You are walking along a busy traffic-filled street and the cars are passing by as they always have done. However, all does not seem right. The air that you are breathing is not filled with the bitter choking smell of exhaust fumes. There is no engine noise coming from the vehicles. How can this be? The answer is that the vehicles are all powered by fuel cells. Once confined to the realms of science fiction, the full commercialization of fuel cells could be just around the corner. Computational chemistry techniques, in particular molecular modeling and simulation, are being used to understand and refine the science driving this quiet, green revolution.Fuel cells were invented in 1839 by Sir William Grove, a Welsh judge and gentleman scientist, as a result of his experiments on the electrolysis of water. To put it simply, fuel cells are electrochemical devices that take hydrogen gas from fuel, combine it with oxygen from the air, and generate electricity and heat, with water as the only by-product.     

Development of fast fabrication method for cylindrical-shaped grids and mechanical properties of CFRP pressure vessel reinforced with cylindrical-shaped grids

In order to reduce carbon dioxide and air pollution emissions, fuel cell vehicles (FCVs) are being developed, and CFRP pressure vessels have been used as the hydrogen storage systems for the FCVs. Since the FCVs are expected to increase driving distances of at least over 500 km, which is similar to those of conventional gasoline-fueled vehicles, the storage pressure of hydrogen must be raised from 35 to 70 MPa. It is important to decrease the amount of carbon fibers in order to reduce the cost and weight of the CFRP pressure vessels. In this study, a fast fabrication method for the cylindrical-shaped grids (CSG) composed of hoop stiffeners and helical stiffeners was developed with a particular mandrel and a 3-axis filament winding apparatus. Then, the CFRP pressure vessel was inserted into the CSG, and burst tests of the CFRP pressure vessels reinforced with and without the CSG were conducted. Moreover, their experimental results were compared with numerical ones obtained by a FEM analysis, and the mechanical properties and the reinforcement effects of the CFRP pressure vessels reinforced with the CSG were investigated.     

航空环境工程与科学

阐述了航空对环境的影响及航空环保工程技术,分析了飞机排放对大气的污染及航空噪声的影响;研究了控制飞机排气污染和噪声污染的办法,提出了降低航空污染的技术和管理措施。     

低温等离子体技术脱除大气污染物的研究进展

随着人们对低温等离子体的不断深入了解,低温等离子体技术具有了更广阔的应用前景;利用低温等离子体技术治理大气污染也是目前很有吸引力和发展前景的技术.主要介绍了低温等离子体应用于大气污染治理的研究进展;分别讨论了低温等离子体在处理含氮氧化物工业废气、含硫工业废气、可挥发性有机污染物等方面的应用及其研究进展,并对低温等离子体脱除大气污染技术进行了展望.     

Safe airport operation based on innovative magnetic detector system

A novel magnetic sensing technology that forms the basis of an innovative system to monitor ground vehicle movements at airports is presented. The operating principle of this system is the detection of interaction of aircraft or ground vehicles with the earth?s magnetic field using sensitive magnetic field detectors. After development and laboratory testing of the detectors, test sites have been set up at three European airports. Potential applications of the detectors were designed and demonstrated. Tests have shown that the system can be applied for ground movement surveillance. The approach can be used as a complementary surveillance system for existing and future advanced surface movement guidance and control systems (A-SMGCS) at large airports or as a cost-effective stand-alone solution for monitoring critical areas at medium and small airports. Furthermore, this system can be applied as well in road traffic and car park occupancy monitoring. Unaffected by weather conditions, interference and shadowing effects, the system provides reliable vehicle position, velocity and direction information without requiring any equipment in aircraft or ground vehicles and thus it increases airport operational safety.     

The engineering options for mitigating the climate impacts of aviation

Aviation is a growing contributor to climate change, with unique impacts due to the altitude of emissions. If existing traffic growth rates continue, radical engineering solutions will be required to prevent aviation becoming one of the dominant contributors to climate change. This paper reviews the engineering options for mitigating the climate impacts of aviation using aircraft and airspace technologies. These options include not only improvements in fuel efficiency, which would reduce carbon dioxide (CO2) emissions, but also measures to reduce non-CO2 impacts including the formation of persistent contrails. Integrated solutions to optimize environmental performance will require changes to airframes, engines, avionics, air traffic control systems and airspace design.While market-based measures, such as offset schemes and emissions trading, receive growing attention, this paper sets out the crucial role of engineering in the challenge to develop a 'green air traffic system'.     

Levelized costs of the energy chains of new energy vehicles targeted at carbon neutrality in China

The diffusion of new energy vehicles (NEVs), such as battery electric vehicles (BEVs) and fuel cell vehicles (FCVs), is critical to the transportation sector’s deep decarbonization. The cost of energy chains is an important factor in the diffusion of NEVs. Although researchers have addressed the technological learning effect of NEVs and the life cycle emissions associated with the diffusion of NEVs, little work has been conducted to analyze the life cycle costs of different energy chains associated with different NEVs in consideration of technological learning potential. Thus, relevant information on investment remains insufficient to promote the deployment of NEVs. This study proposes a systematic framework that includes various (competing or coordinated) energy chains of NEVs formed with different technologies of power generation and transmission, hydrogen production and transportation, power-to-liquid fuel, and fuel transportation. The levelized costs of three typical carbon-neutral energy chains are investigated using the life cycle cost model and considering the technological learning effect. Results show that the current well-to-pump levelized costs of the energy chains in China for BEVs, FCVs, and internal combustion engine vehicles (ICEVs) are approximately 3.60, 4.31, and 2.21 yuan/GJ, respectively, and the well-to-wheel levelized costs are 4.50, 6.15, and 7.51 yuan/GJ, respectively. These costs primarily include raw material costs, and they vary greatly for BEVs and FCVs from resource and consumer costs. In consideration of the technological learning effect, the energy chains’ well-to-wheel levelized costs are expected to decrease by 24.82% for BEVs, 27.12% for FCVs, and 19.25% for ICEVs by 2060. This work also summarizes policy recommendations on developing energy chains to promote the diffusion of NEVs in China.     

Review of fuel processing catalysts for hydrogen production in PEM fuel cell systems

The rapid development in recent years of the proton-exchange membrane (PEM) fuel cell technology has stimulated research in all areas of fuel processor catalysts for hydrogen generation. The principal aim is to develop more active catalytic systems that allow for the reduction in size and increase the efficiency of fuel processors. The overall selectivity in generating a low CO content hydrogen stream as needed by the PEM fuel cell catalyst is dependent on the efficiency of the catalysts in each segment of the fuel processor. This article reviews the advances achieved during the past few years in the development of catalytic materials for hydrogen generation through fuel reforming,¹ water-gas shift and carbon monoxide preferential oxidation, as used or aimed to be of use in fuel processing for PEM fuel cell systems.     

一种民用客机航线平均油耗评估模型

为了解决现有燃油评估模型无法准确指导民机市场需求分析和航空碳排放收费政策制定的缺陷,通过对航空公司各主要机型航线生产运营数据的统计分析,运用灰色关联分析法与相关系数法确定了影响航线平均油耗水平的主要宏观影响因素,采用回归分析法分析了机型航线燃油消耗水平与航段距离的关系,并确定了民机设计航程与座位数对线性回归参数的影响,以此构建了民用客机航线平均油耗水平模型的解析表达式。利用11种样本机型产生的275条数据对解析表达式进行参数估计,拟合优度达到0.9979,通过对11种机型产生的16条样本数据进行预测检验,发现统计回归模型的平均相对误差为0.0379,预测精度较高,因此模型切实可行。     

Thermodynamic analysis of a demonstration concept for the long-duration storage and transfer of cryogenic propellants

In the development of a concept for an experimental platform for demonstrating technologies associated with the on-orbit handling, transfer and storage of cryogenic propellants, credibility is enhanced with simulations of operations using thermodynamic models. Predictions have further credibility if the modeling technique is verified against simulations of actual cryogenic fuel transfers during ground testing. This paper will demonstrate the capability of simulating the transfer of liquid hydrogen as preformed at NASA’s Glenn Research Center. Results of simulations of an experimental space mission developed at Ball Aerospace will then follow. The mission concept is intended to demonstrate the technologies and storage methodologies for supporting long-term storage and transfer of cryogenic fuels in space.     

Emissions from Transportation and Fuels: The Importance of Initial and Real World Measurements for Policy Making in India

Air pollution is typically one of the by-products of a growing economy, especially in the developing world. India is no exception. This paper highlights the importance of acquiring reliable, real world data, which is necessary for making sound policy decisions. Using examples where real world emissions of nitrogen oxides exceed those obtained during vehicle emission test procedures, recommendations are made for India in designing and applying an air quality management system, which relates emissions, meteorology and atmospheric chemistry to ambient air quality concentrations. Specific recommendations are made to require Euro 6/VI vehicle emission standards by 2019 and nationwide ultra low sulfur fuels by 2015 (50 ppm) and 2017 (10 ppm). Controls of evaporative emission during refueling should be implemented by 2017. Recommendations are also made for improved initial vehicle emission testing, routine testing of fuels being sold in the marketplace, and an enforceable vehicle in use emission testing program.     

Nanostructures in environmental pollution detection,monitoring, and remediation

We present preliminary results of our joint investigations to monitor and mitigate environmental pollution, a leading contributor to chronic and deadly health disorders and diseases affecting millions of people each year. Using nanotechnology-based gas sensors; pollution is monitored at several ground stations. The sensor unit is portable, provides instantaneous ground pollution concentrations accurately, and can be readily deployed to disseminate real-time pollution data to a web server providing a topological overview of monitored locations. We are also employing remote sensing technologies with high-spatial and spectral resolution to model urban pollution using satellite images and image processing. One of the objectives of this investigation is to develop a unique capability to acquire, display and assimilate these valuable sources of data to accurately assess urban pollution by real-time monitoring using commercial sensors fabricated using nanofabrication technologies and satellite imagery. This integrated tool will be beneficial towards prediction processes to support public awareness and establish policy priorities for air quality in polluted areas. The complex nature of environmental pollution data mining requires computing technologies that integrate multiple sources and repositories of data over multiple networking systems and platforms that must be accurate, secure, and reliable. An evaluation of information security risks and strategies within an environmental information system is presented. In addition to air pollution, we explore the efficacy of nanostructured materials in the detection and remediation of water pollution. We present our results of sorption on advanced nanomaterials-based sorbents that have been found effective in the removal of cadmium and arsenic from water streams.     

Macro-level optimized deployment of an electrolyser-based hydrogen refuelling infrastructure with demand growth

Hydrogen-powered vehicles are receiving a significant amount of attention due to their potential for reduced greenhouse gas emissions, increased production pathways, and the higher efficiencies of fuel cells as compared to internal combustion engines. A major obstacle to the commercialization of hydrogen vehicles is the lack of a developed hydrogen refuelling infrastructure. A cost-effective infrastructure requires a significant number of hydrogen-powered vehicles in use. A plausible solution to the ‘chicken and egg’ dilemma requires the development of an infrastructure prior to competitive economic viability. This article employs optimization techniques to design a public-policy-supported infrastructure at minimum cost as the number of hydrogen vehicles increases from 10 to 100,000. The specific case used is the development of an infrastructure across a major Canadian highway spanning South Ontario and Western Quebec.     

航空技术的发展趋势和创新基地建设

面对21世纪的需要,下一代航空器将飞得更快、尺寸更大、更经济安全、消耗资源更少。载客1 000人的大型飞机、高超音速飞机、微型无人机、地效飞机、倾转旋翼飞机等将交付使用。为减少污染和对石油的依赖,将采用替代燃料。飞机的经济性、安全性、环保性能将有成倍甚至成十倍地提高。面对挑战,必须加强航空技术创新基地建设。