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Technical Paper

Status, Vision, and Challenges of an Intelligent Distributed Engine Control Architecture

2007-09-17
2007-01-3859
A Distributed Engine Control Working Group (DECWG) consisting of the Department of Defense (DoD), the National Aeronautics and Space Administration (NASA)- Glenn Research Center (GRC) and industry has been formed to examine the current and future requirements of propulsion engine systems. The scope of this study will include an assessment of the paradigm shift from centralized engine control architecture to an architecture based on distributed control utilizing open system standards. Included will be a description of the work begun in the 1990's, which continues today, followed by the identification of the remaining technical challenges which present barriers to on-engine distributed control.
Technical Paper

Reliable Bearing Wear Detection System for On-Condition Maintenance of Electric Generators

2002-11-05
2002-01-2951
Demand on the reliability of Electric Generators for Aerospace applications is assuming more importance everyday with the advent of “Fly-by-Wire” and “More-Electric-Aircraft” concepts. With today's high-powered avionics and sophisticated control systems, airline operators expect better performance and would no longer accept weak links in the system that need frequent maintenance. One of the weakest points in an electric generator is its reliance on rolling element bearings, which are subject to unpredictable and frequent failures. Huge redundancy and frequent maintenance ensure uninterrupted supply of electricity in an aircraft.
Technical Paper

Performance Evaluation of a Three-Stage Vacuum Rotary Distillation Processor

2000-07-10
2000-01-2386
Simulated spacecraft water recovery wastewater feed streams were purified with a three-stage vacuum rotary distillation processor (TVRD) during a series of tests conducted to evaluate the operation of this technology. The TVRD was developed to efficiently reclaim potable water from urine in microgravity by NIICHIMMASH (Moscow, Russia). A prototype was evaluated at the Honeywell Space Water Reclamation test lab, where a special test setup was assembled to evaluate the performance of the TVRD. This paper discusses the TVRD technology, test description, test results, and performance analysis. Tests were conducted using four streams of wastewater: pretreated human urine, bioprocessor effluent, reverse osmosis brine ersatz, and deionized water. The testing demonstrated that greater than 90 percent water recovery can be reached with production rates of 2.2 to 2.9 kg/hr (4.84 to 6.30 lb/hr).
Technical Paper

Nitrogen Removal from a Urine-Soap Wastewater Using a Bioprocessor System: Process Monitoring and Control

2002-07-15
2002-01-2353
A detailed study was conducted on nitrification using a bench top bioprocessor system proposed for water recycling of a urine-soap wastewater expected to be generated by crewmembers on International Space Station (ISS) or similar long-term space missions. The bioprocessor system consisted of two packed bed biofilm reactors; one anoxic reactor used for denitrification and one aerobic reactor used for nitrification. lnfluent wastewater was a mixture of dilute NASA whole body soap (2,300 mg/L) and urea (500 mg/L as organic nitrogen). During two months of steady-state operation, average chemical oxygen demand (COD) removal was greater than 95%, and average total nitrogen removal was 70%. We observed that high levels of nitrite consistently accumulated in the aerobic (nitrifying) reactor effluent, indicating incomplete nitrification as the typical end product of the reaction would be nitrate.
Technical Paper

Modeling and Analysis of Bus Voltage Control in Aerospace Applications

2008-11-11
2008-01-2868
This work deals with the modeling and analysis of both AC and DC bus voltage control in aerospace applications. The results of the analysis are presented along with system models, including a voltage-controlled current source (vccs) used as a DC Bus controller, a d,q-controlled, IGBT-based, SVPWM-switched, ac-to-dc active converter/rectifier (AR) used as a DC Bus controller, a 3-phase ac generator voltage regulator (VR) used as an AC Bus controller, a 3-phase uncontrolled ac generator followed by an SCR-controlled ac-to-dc converter, used as a DC Bus controller (single-controlled bus), and a 3-phase dynamically-controlled ac generator followed by an SCR-controlled ac-to-dc converter, used to provide both AC and DC Bus control (dual-controlled bus).
Technical Paper

Integrated Modular Concepts for Improved ECLSS Command and Data Handling

2006-07-17
2006-01-2122
Current Environmental Control and Life Support Systems (ECLSS), particularly on large systems, have a tendency to include several heterogeneous processing elements. This approach is also the default in the commercial aircraft industry. However, Honeywell has been extremely successful in the past decade in using an integrated modular approach to command and data handling for aircraft avionics. This approach, dubbed “Fifth Generation Avionics” by the Air Force's Wright Laboratory, has resulted in significant reductions in the size, weight, power, and acquisition costs of the data handling subsystem. Logistics, modification, and upgrade costs also decreased considerably. While commonality is maximized in the integrated modular architecture, each application continues to be independent with internal designs completely under the control of the application developer.
Technical Paper

Inerting Aircraft Fuel Tanks - Reducing the Hazard

2000-07-10
2000-01-2267
Aircraft accidents caused by explosion of the vapor within the fuel tanks have been the subject of many recent articles. Methods of either suppressing the combustion or preventing the ignition have been considered. Indeed, solutions such as liquid nitrogen, halon, and reticulated foam have been installed on production aircraft. However, these have proved to be expensive to operate or are being phased out. By working together, the authors have developed the capability to provide fully integrated On-Board Inert Gas Generating Systems (OBIGGS) based on novel hollow fiber membrane technology. An overview of the advantages of such an approach is presented together with an outline of the system design method. The importance of considering the effect of differing flight profiles, and the inter-reactions of the OBIGGS, with the Fuel System, Engine Bleed Air Management, and Environmental Control Systems in the design process are emphasized.
Technical Paper

Industry Activities Related to Aircraft Information Security

2007-09-17
2007-01-3919
Commercial transport aircraft have adopted TCP/IP based onboard networking technology to integrate information interchange. This change along with the addition of a TCP/IP based air-ground data link will permit the aircraft network to establish links with ground networks and be integrated into the airline enterprise network. There are many challenging considerations when connecting a remote network to an enterprise network. These challenges are multiplied when that remote network is constantly in motion, both physically and in terms of its link to the ground network. An important consideration in any enterprise network is the element of security. AEEC has published ARINC Report 811: Commercial Aircraft Information Security Concepts of Operation and Process Framework [1] as a guide for the airlines as they consider how to deal with this new challenge.
Journal Article

Incorporation of Atmospheric Neutron Single Event Effects Analysis into a System Safety Assessment

2011-10-18
2011-01-2497
Atmospheric Neutron Single Event Effects (SEE) are widely known to cause failures in all electronic hardware, and cause proportionately more failures in avionics equipment due to the use altitude. In digital systems it is easy to show how SEE can contribute several orders of magnitude more faults than random (hard) failures. Unfortunately, current avionics Safety assessment methods do not require consideration of faults from SEE. AVSI SEE Task Group (Aerospace Vehicle Systems Institute Committee #72, on Mitigating Radiation Effects in Avionics) is currently coordinating development of an atmospheric Neutron Single Event Effects (SEE) Analysis method. This analysis method is a work in progress, in close collaboration with SAE S-18 and WG-63 Committees (Airplane Safety Assessment Committee). The intent is to include this method as part of current revisions to ARP4761 (Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment).
Journal Article

Incorporating Atmospheric Radiation Effects Analysis into the System Design Process

2012-10-22
2012-01-2131
Natural atmospheric radiation effects have been recognized in recent years as key safety and reliability concerns for avionics systems. Atmospheric radiation may cause Single Event Effects (SEE) in electronics. The resulting Single Event Effects can cause various fault conditions, including hazardous misleading information and system effects in avionics equipment. As technology trends continue to achieve higher densities and lower voltages, semiconductor devices are becoming more susceptible to atmospheric radiation effects. To ensure a system meets all its safety and reliability requirements, SEE induced upsets and potential system failures need to be considered. The purpose of this paper is to describe a process to incorporate the SEE analysis into the development like-cycle. Background on the atmospheric radiation phenomenon and the resulting single event effects, including single event upset (SEU) and latch up conditions is provided.
Technical Paper

Heat Exchanger Fouling Detection in Aircraft Environmental Control Systems

2012-10-22
2012-01-2107
The operating environment of aircraft causes accumulation and build-up of contamination on both the narrowest passages of the ECS (Environmental Control System) i.e: the heat exchangers. Accumulated contamination may lead to reduction of performance over time, and in some case to failures causing AOG (Aircraft on Ground), customer dissatisfaction and elevated repair costs. Airframers/airlines eschew fixed maintenance cleaning intervals because of the high cost of removing and cleaning these devices preferring instead to rely on on-condition maintenance. In addition, on-wing cleaning is t impractical because of installation constrains. Hence, it is desirable to have a contamination monitoring that could alert the maintenance crew in advance to prepare and minimize disruption when contamination levels exceed acceptable thresholds. Two methods are proposed to achieve this task, The effectiveness of these methods are demonstrated using analytical and computational tools.
Journal Article

Health Ready Components-Unlocking the Potential of IVHM

2016-04-05
2016-01-0075
Health Ready Components are essential to unlocking the potential of Integrated Vehicle Health Management (IVHM) as it relates to real-time diagnosis and prognosis in order to achieve lower maintenance costs, greater asset availability, reliability and safety. IVHM results in reduced maintenance costs by providing more accurate fault isolation and repair guidance. IVHM results in greater asset availability, reliability and safety by recommending preventative maintenance and by identifying anomalous behavior indicative of degraded functionality prior to detection of the fault by other detection mechanisms. The cost, complexity and effectiveness of the IVHM system design, deployment and support depend, to a great extent, on the degree to which components and subsystems provide the run-time data needed by IVHM and the design time semantic data to allow IVHM to interpret those messages.
Technical Paper

Development and Application of a Real Time Bleed Air Contamination Monitor

2002-11-05
2002-01-2925
The bleed air contamination monitor was developed at Honeywell to ensure that our products provide the highest quality bleed air to aircraft environmental control systems. The bleed air contamination monitor is currently for ground based applications only. It is being developed into an on board system for future applications. Current Aircraft Cabin Air Quality measurement techniques are very labor intensive and require days or even weeks of laboratory analysis to provide results. This is unacceptable from a manufacturing and service perspective. Development of a real time analyzer began in the early 1990s and has progressed to a point where a product is ready for introduction that not only provides real time information regarding engine air contamination, but is also easy for operators to use with a minimum amount of training.
Technical Paper

Designing User-Interfaces for the Cockpit: Five Common Design Errors and How to Avoid Them

2002-11-05
2002-01-2968
The efficiency and robustness of pilot-automation interaction is a function of the volume of memorized action sequences required to use the automation to perform mission tasks. This paper describes a model of pilot cognition for the evaluation of the cognitive usability of cockpit automation. Five common cockpit automation design errors are discussed with examples.
Technical Paper

Corrosion Testing of Brazed Space Station IATCS Materials

2004-07-19
2004-01-2471
Increased nickel concentrations in the IATCS coolant prompted a study of the corrosion rates of nickel-brazed heat exchangers in the system. The testing has shown that corrosion is occurring in a silicon-rich intermetallic phase in the braze filler of coldplates and heat exchangers as the result of a decrease in the coolant pH brought about by cabin carbon dioxide permeation through polymeric flexhoses. Similar corrosion is occurring in the EMU de-ionized water loop. Certain heat exchangers and coldplates have more silicon-rich phase because of their manufacturing method, and those units produce more nickel corrosion product. Silver biocide additions did not induce pitting corrosion at silver precipitate sites.
Technical Paper

Biological Wastewater Processor Experiment Definition

2000-07-10
2000-01-2468
The Biological Wastewater Processor Experiment Definition team is performing the preparatory ground research required to define and design a mature space flight experiment. One of the major outcomes from this work will be a unit-gravity prototype design of the infrastructure required to support scientific investigations related to microgravity wastewater bioprocessing. It is envisioned that this infrastructure will accommodate the testing of multiple bioprocessor design concepts in parallel as supplied by NASA, small business innovative research (SBIR), academia, and industry. In addition, a systematic design process to identify how and what to include in the space flight experiment was used.
Technical Paper

Aircraft Electric Brakes - Technical Development

2002-11-05
2002-01-2946
The design, development and testing of electric brakes for the DARPA/USAF/Boeing X-45A Unmanned Combat Air Vehicle (UCAV) demonstrator is discussed. The UCAV effort presented a new set of challenges and capability requirements for the brake system. A selection of electric brake technical development results is presented.
Technical Paper

Advanced Electric Generators for Aerospace More Electric Architectures

2010-11-02
2010-01-1758
This paper discusses the problem of designing electric machines (EM) for advanced electric generators (AEG) used in aerospace more electric architecture (MEA) that would be applicable to aircraft, spacecraft, and military ground vehicles. The AEG's are analyzed using aspects of Six Sigma theory that relate to critical-to-quality (CTQ) subjects. Using this approach, weight, volume, reliability, efficiency, and cost (CTQs) are addressed to develop a balance among them, resulting in an optimized power generation system. The influence of the machine power conditioners and system considerations are also discussed. As a part of the machine evaluation process, speeds, bearings, complexities, rotor mechanical and thermal limitations, torque pulsations, currents, and power densities are also considered. A methodology for electric machine selection is demonstrated. Examples of high-speed, high-performance machine applications are shown.
Technical Paper

Active vs. Passive Means of Power Quality Improvement in Aerospace Applications

2002-10-29
2002-01-3226
The issues of active vs. passive means of power quality improvement in aerospace applications are addressed. The concept of nonlinear load, i.e., the relationship between the current harmonics and system power factor has been reviewed. Both passive and active means of harmonic minimization are discussed, including resonance issues associated with passive networks and presenting an active rectifier switched in a Space Vector (SV) Pulse Width Modulation (PWM) manner. The analysis of power quality in aerospace applications is presented, together with the industry governing standards. Results of case studies are given, using Saber hierarchical tools for the system analysis. Both simulation and experimental results are provided, demonstrating power quality improvements in several aerospace applications.
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