Five-year update: nickel hydrogen industry survey

A 1984 survey of the nickel hydrogen (NiH₂) battery industry is updated. Late 1980s and early 1990s issues are identified, and usage and testing results of the survey are summarized. NiH₂ is the system of choice for new geosynchronous-earth-orbit (GEO) satellites and is being seriously considered for low-earth-orbit (LEO) applications. In five years, the annual cell production rate has doubled from approximately 1000 to 2000 cells. A number of cells under test have exceeded 20000 cycles at 40% DOD in LEO regimes, while other cells have achieved over 35 seasons in accelerated GEO regimes. The LEO database clearly indicates that NiH₂ performance is at least as good as the best conventional nickel-cadmium performance demonstrated under test     

Evaluation of nickel-hydrogen battery cells for space-based radar

A study conducted in 1991 on nickel-hydrogen (NiH₂) battery cells, to assess their use for space-based radar satellites, is discussed. Current NiH₂ and related programs were investigated. Cell performance data were assessed, focusing on pulsed-load operation, cell design factors, and life expectancy. A need for pulsed-load testing of candidate cells, especially to characterize their effective series resistance, dynamic impedance, and possible degradations, was identified. A NiH₂ cell test program was planned, and test preparations started in mid-1992     

Effect of KOH concentration on LEO cycle life of IPVnickel-hydrogen flight cell-update II

For update I see Energy and Environment: A Continuing Partnership, vol.3, American Nuclear Society (1991). An update of validation test results confirming the breakthrough in the low-Earth-orbit (LEO) cycle life of nickel-hydrogen cells containing 26% KOH electrolyte is presented. The results are part of an investigation of the effect of KOH concentration on life cycle. The cycle life of boiler plate cells was about 40000 LEO cycles compared to 3500 cycles for cells containing 31% KOH. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min discharge (2×normal rate). The depth-of-discharge (DOD) was 80%. The cell temperature was maintained at 23°C. Results for six 48-Ah recirculation design IPV nickel-hydrogen flight battery cells currently being evaluated to validate the above findings are reported. Three of the cells contain 26% KOH (test cells), and three contain 31% KOH (control cells). They are undergoing real-time LEO cycle life testing. The 31% KOH cells failed at cycles 3729, 4165, and 11355. One of the 26% KOH cells failed at cycle 15314. The other two 26% KOH cells have been cycled for over 16600 cycles without failure     

Advances in the development of ovonic nickel metal hydridebatteries for industrial and electric vehicles

The environmental advantages of ovonic NiH₂ batteries, due to the nontoxicity of ovonic alloys, are briefly discussed, and their general performance is described. Commercial progress in their development is summarized. Their use in electric vehicles is examined     

Life expectancy of a 24-V, 15-Ah sealed lead-acid aircraft battery

This paper presents the results of cycle life testing F24-V, 15-Ah sealed lead-acid batteries intended for use the B-1B aircraft. Test samples were procured from two different manufacturers and subjected to cycle testing at 33% and 100% depth-of-discharge (DOD). The cycle life at 33% DOD ranged from 500 to 750 cycles. The cycle life at 100% DOD ranged from 160 to 260 cycles     

试论教练装备空海军联合发展

阐述了美国空军和海军教练机装备发展现状,分析了美国空军和海军教练机装备联合发展的过程、原因以及优势,并结合我国空军和海军教练机的发展情况,得出我国空/海军教练机装备联合发展的几点启示。     

Development of a long cycle life sealed nickel-zinc battery forhigh energy-density applications

Nickel-zinc battery technology is being developed for commercial applications requiring high energy density and high power capability. Development cells have demonstrated the ability to deliver over 60 Watt-hours per kilogram at the one hour rate. Cycle life has been improved to more than 600 cycles at 80% depth of discharge by using a patented, reduced solubility zinc electrode and an improved sealed cell design. More than 8000 charge/discharge cycles at 10% depth-of-discharge have been completed. Large quantities of sealed prismatic cells have been manufactured, including a 140 cell, 220 V battery for a hybrid electric vehicle (HEV)     

US Air Force EarthRadar for detection and discrimination of buriedunexploded ordnance

The US Air Force EarthRadar system is a multi-purpose sensor designed and constructed using "radar" principles. This technology was originally developed for the US Air Force to detect buried unexploded ordnance (UXO). Bakhtar Associates developed the US Air Force EarthRadar technology under the DoD SBIR program. The system is capable of detecting buried metallic and non-metallic objects, including glass vials. In addition, the manner in which system hardware, signal processing, and the integrated high resolution global positioning system (GPS) are configured makes it ideal for applications such as mapping subsurface geological features, locating cavities and collapse features, and identifying contaminated ground     

PowerCore combining structure and batteries for increased energy toweight ratio

Much of the mass of a battery is comprised of nonreactive materials. In an NiH₂ battery, this includes the pressure vessel and 50% of the positive electrode. PowerCore reconfigures the battery materials to serve as a structural sandwich panel. The effective specific energy of the new device can exceed 100 Wh/kg. PowerCore is intended to handle power demands of low Earth orbiting communications satellites such as IRIDIUM. This paper describes the concept and development progress     

Lightweight (AlGaAs)GaAs/CuInSe2 tandem junction solarcells for space applications

Mechanically stacked tandem cells consisting of GaAs thin-film upper cells and CuInSe₂ thin-film lower cells have been developed to meet the increasing power needs projected for future spacecraft. The authors report the fabrication of the first highly efficient lightweight GaAs/CuInSe₂ tandem cell on a 2-mil thick substrate, update recent performance improvements in thin-film GaAs/CuInSe₂ tandem cells, and discuss their application to space power systems. The efficiency of 4-cm² cells has improved to 21.6% AM0, the highest ever reported for a thin-film photovoltaic cell. Lightweight 4-cm² tandem cells have been successfully fabricated with efficiencies as high as 20.8%. These cells weighed about 180 mg without optimized substrate trimming. Radiation and operating temperature effects on GaAs/CuInSe₂ tandem cells are also discussed, and an interconnect scheme to form a voltage-matched string is described     

AFRL Cryogenic Technology Development Programs

This is an overview of the cryogenic refrigerator and cryogenic integration programs in development and characterization under the Cryogenic Technologies Group, Space Vehicles Directorate of the Air Force Research Laboratory (AFRL). The vision statement for the Air Force Research Laboratory Cryogenic Technologies Group is to support the space community as the center of excellence for developing and transitioning space cryogenic thermal management technologies. The primary customers for the AFRL cryogenic technology development programs are Ballistic Missile Defense Organization (BMDO), the USAF SBIRS (space based infrared) Low program office, and DoD space surveillance programs. This describes a variety of Stirling, pulse tube, Reverse Brayton, Joule-Thomson, and Sorption cycle cryocoolers currently under development to meet current and future Air Force and DoD requirements. The AFRL customer single stage cooling requirements at 10 K, 35 K, 60 K, 150 K, and multi-stage cooling requirements at 35/60 K are addressed. In order to meet these various requirements, the AFRL Cryogenic Technologies Group is pursuing various strategic cryocooler and cryogenic integration options. The Air Force Research Laboratory is also developing several advanced cryogenic integration technologies that will result in the reduction in current cryogenic system integration penalties and design time. These technologies include the continued development of the cryogenic systems integration model (CSIM), 60 K, and 100 K thermal storage units and heat pipes, cryogenic straps, thermal switches, and development of an integrated lightweight cryogenic bus (CRYOBUS).     

WJ5A压气机改型设计及试验结果

本文简介了 WJ5A压气机的改型设计,对比了该压气机改型前后的试验性能。试验表明:该压气机改型后性能得到了较大的提高。在相对折合转速 η_np1 =1.00的条件下,其最大效率η*_kmax增加3.6;n_np1 =0.70～0.90时,η*_kmax增加15%以上。在各转速下,压比和流量均有少许变化。      

航空兵部队飞行安全评估系统研究与实践

根据航空兵部队飞行安全的特点,基于“人、机、环境“系统工程理论,并结合航空兵部队的实际,开发了一套航空兵部队飞行安全评估系统.该系统具有客观评估安全形势、发现薄弱环节和引导航空兵部队安全行为的功能.最后,给出了对航空兵部队进行飞行安全评估的应用实例.     

An automated test approach for US Air Force fighter engines

In an effort to support the Air Force's new F-22 Fighter aircraft with its dual F119-PW-100 jet engines, a new approach has been taken to realize the benefits of automated jet engine testing. This paper describes an automated test approach that is currently under development and will be used by the Air Force to test the F119 jet engine; It also identifies; the equipment, methods and techniques that are being employed to accomplish this task     

Prismatic lithium-ion batteries

Lithium-ion (Li-ion) batteries have demonstrated the ability to fulfill the energy storage needs of many new technologies. The most significant drawbacks of currently available technologies, such as LiCoO ₂ based Li-ion cells, is their high cost and significant environmental hazards. Li-ion cells which use a lithium manganese oxide (LiMn₂O₄) spinel based cathode material should be much less costly and safer than LiCoO₂ based cells. Performance data from prismatic design cells which use a LiMn₂O₄ based cathode material is presented and shown to meet many military performance criteria. The most significant drawback of this technology is the short cycle life     

Spiral evolution applied to legacy avionics systems

The US Department of Defense (DoD), through the Office of the Secretary of Defense (OSD), has determined that evolutionary acquisition is their strategy of choice for future software-intensive systems, and that the spiral development model (SDM) is the preferred method/process for software-intensive development life cycles. Electronic Systems Command (ESC) at Hanscom AFB, Massachusetts, has written a draft handbook on the use of Spiral Development for all future Command and Control (C2) systems, including reference to the DoD 5000 series and Air Force Program Directive 63-1, Acquisition System, which deploys this OSD mandate for future C2 systems. Barry Boehm's continued work on SDM which he conceived in the 1980s, is heavily biased toward development of new systems that are software-intensive, as noted in a workshop he gave at the Software Engineering Institute (SEI) in 2000.     

High Voltage/High Power for Airborne Applications

The Air Force has requirements for large amounts of electrical power at high voltage (up to hundreds of kilovolts) for certain airborne applications. Because of the severe weight and volume constraints, these systems cannot be realized using conventional technology. The Air Force, therefore, has been heavily involved in the development of lightweight power generation and conditioning equipment. Programs have been undertaken to reduce the weight of rotating machines, transformers, switches, inverters, and capacitors. The advances made in these areas are described, and some aspects of the use of these components in the design of lightweight systems are discussed.     

Life cycle testing of a sealed 24-V, 42-Ah nickel-cadmium aircraftbattery

Extensive research has been conducted in the design and manufacture of very long life sealed maintenance free nickel-cadmium aircraft batteries. This study presents data on a 100% depth of discharge (DOD) life test performed on a nominal capacity 42-Ah battery. The purpose of this study is to validate design concepts, determine the life characteristics of the newly designed sealed Ni-Cd batteries, and develop baseline information on failure rates and mechanisms. The data from this experiment can be used to compare depth of discharge versus battery life with similar tests such as the lower DOD experiments performed on spacecraft batteries. This information is important in the ongoing development of long life batteries and in developing failure models for life prediction     

Safety,environment, ATM: Three key issues!

Demand for air travel increases rapidly - world-wide by about 5% annually. Between 2000 and 2020 more than 14,000 large new airliners will have been delivered to create a world fleet of 20,000 airliners after old types are withdrawn. About 40% of world-wide air travel has a European arrival or departure point. What are consequences of these predictions? This article introduces the section on Air Transport, where these problems will be covered in more depth.