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Thermal Analysis of Aircraft Auxiliary Power Unit: Application of Chemical Looping Combustion

National Institute of Technology-Prashant Kumar, MD AKRAM, Anand Shankar Singh, Sanjay S
Published 2019-03-19 by SAE International in United States
An “APU” (Auxiliary Power Unit) is a small gas turbine engine to provide supplementary power to an aircraft and is located at the tails of larger jets. APU generators provide auxiliary electrical power for running aircraft systems on the ground. Applications include powering environmental systems for pre-cooling or preheating the cabin, and providing power for crew functions such as preflight, cabin cleanup, and galley (kitchen) operation and long-haul airliners must be started using pneumatic power of APU compressor. The Honeywell 131-9A gas turbine APU has 440 kW shaft power and 90 kW electric generator consuming 120 kg fuel/hour. Here the traditional combustor of the APU is proposed to be replaced by a chemical-looping-combustion (CLC) system. CLC system consist of two reactor one is oxidation reactor (air reactor) and the other is reduction reactor (fuel reactor).The system is fluidized bed system in which activated metal-oxide(MeO) participates and circulates between the reactors .The metal-oxide (MeO) provides oxygen for combustion in the fuel reactor. The reduced metal is then transferred to air reactor before being reintroduced to the…
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Regression Techniques for Parameter Estimation of a Synchronous Machine from Sudden Short-Circuit Testing

P.C. Krause And Associates Inc.-Brett A. Robbins, Will Perdikakis
US Air Force-Kevin J. Yost
Published 2019-03-19 by SAE International in United States
A sudden short-circuit (SSC) laboratory test of an electric machine is a commonly used procedure to estimate model parameters that accurately represent the dynamic response of the machine. While the graphical interpretation of the short-circuit current is often discussed in great detail, the numerical methods used to determine the solution for the machine parameter estimation is a challenging proposition. In this paper, the authors present an integral regression technique to fit the characteristic equation of the short-circuit current to a curve that is composed of exponential decays that trail off to an unknown steady-state value in the presence of noise. The proposed estimation method is applied to laboratory data from an aerospace synchronous machine.
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A Dynamic Fault Tree Approach for Time-Dependent Logical Modeling of Autonomous Flight Systems

Cobham Mission Systems Inc-John Wang
Published 2019-03-19 by SAE International in United States
This paper addresses the urgent need for adequate methodologies to use in analyzing autonomous flight systems, including Unmanned Aircraft. These systems are inherently dynamic and require analysis that is explicitly time dependent. Autonomous flight systems are becoming more commonly used, especially for Part 23 aircraft including Business (Corporate) and Regional Jets or Unmanned Aircraft deployed in hazardous environment/situation. Such systems are expected to make their own decisions under uncertain conditions caused by potential system structure changes when entering a new flight phase or switching to a new system configuration due to system degradation or failure(s) [1]. This paper highlights significant modeling errors that can arise in analyzing dynamic scenarios where these time dependencies are ignored. Model-based solutions are provided by incorporating a time-dependent algebraic formalism into Fault Tree Analysis (FTA) and Dependency Diagram (DD) with updated descriptions in SAE ARP4761A and ARP4754B (Note: These are currently under development). A Dynamic Goal Tree (or alternatively, a Dynamic Dependency Diagram) provides an effective implementation of the time-dependent logic for dynamic system analysis analyzing autonomous flight systems which…
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Enabling Expanded Aerospace Automation Using Tactile Cognition Analytics

Northrop Grumman Aerospace-George Nicholas Bullen
Published 2019-03-19 by SAE International in United States
Aerospace assembly operations are still highly dependent on human labor and processes. This paper will describe and illustrate the transformational technologies that will enable replication of the human cognitive (in context) textural ability to assemble airplane and space structure. The paper will also provide use case examples where these innovative technologies have been applied successfully.Without context, data are just dots, floating around without meaning. With context data becomes an enlightened component of knowledge that brings value to information. In-context enlightened knowledge provides manufacturing visibility within factory operations. Visibility is a key component of the Smart, Brilliant, or Intelligent Factory.
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Development of the Next Generation Flexible Tooling System

Larry Kirby, Ronald Weddle
Published 2019-03-19 by SAE International in United States
Flexible Tooling Systems have been developed as a reconfigurable part support system to enable trimming of multiple part geometries utilizing a single router or waterjet. The driver for this development has been improved part quality, elimination of ergonomic issues associated with manually trimming, and the elimination of cost for part number specific hard tooling and the associated cost for manufacturing, maintenance, and storage. This paper will briefly trace the evolution of aerospace parts trimming history. The remainder of the report will focus on the technical objectives associated with the development of the Next Generation Flexible Tooling System, how they were achieved including the process for validation of each support location in aircraft coordinates. This system is designed to increase part holding accuracy with specific support location validation, and significantly reduce system maintenance costs in wet or dry environments.
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Tuning Aircraft Engines with OptiStruct Rotor Dynamics Simulation

Altair Engineering-Ujwal Kondavalasa Patnaik, Junji Saiki
GE Aviation-Illya Arcos
Published 2019-03-19 by SAE International in United States
It is typical in aircraft engine design to explore new configurations in a constant effort to achieve greater efficiency with respect to various considerations. An integral component of this process requires a complete and robust simulation of rotor dynamics. Tuning the design with results of rotor dynamics simulations can be made possible with a tool that has adequate modeling techniques to capture the physics associated with engine behavior under various operating conditions accurately.
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Mobile Laser Trackers for Aircraft Manufacturing: Increasing Accuracy and Productivity of Robotic Applications for Large Parts

FFT Produktionssysteme GmbH & Co KG-Fabian Ehmke
Fraunhofer IFAM-Christoph Brillinger, Till Staude, Kevin Deutmarg, Maximilian Klemstein, Christian Boehlmann
Published 2019-03-19 by SAE International in United States
The demand for higher production rates of large parts in aircraft industry requests more flexible manufacturing solutions. High-accurate mobile robots show a promising alternative in comparison with high-invest special machines. With mobile robot-based solutions processes can be executed simultaneously which increases the productivity significantly. However, the freedom of mobility results in insufficient positioning accuracy of these machines. Hence fast and accurate referencing processes are required to achieve cost-effectiveness and meet production tolerances. In this publication a Mobile Laser Tracker (MLT) system and a holistic approach for future manufacturing systems with mobile robots will be introduced and discussed.
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Simulation and Systems Engineering: Lessons Learned

Florida Space Institute-Michael Conroy
University of Central Florida-Luis Rabelo
Published 2019-03-19 by SAE International in United States
Aerospace projects live a long time. Around the turn of the century, NASA first began to discuss multi-decadal projects with respect to the tools, methods, infrastructure and culture necessary to successfully establish outposts and bases both on the Moon as well as in adjacent space. Pilot projects were completed, capabilities developed and solutions were shared across the Agency. A decade later the Mars discussion was multi-generational with planning milestones 50 years in the future. The 1970’s Requirements Document, or the 1990’s System Model are nowhere near suitable for planning, development, integration and operations of multi-national, highly complex, incredibly expensive development efforts planned to outlast not only the careers of the developers but that of their children as well. Simulation in the different forms has become very important for this multi-decadal projects. The challenge will be to device ways to create formats and views which can stand time.This paper will share and discuss challenges, tools, methods, plans, successes and unmet goals associated with development of multi-decadal projects and simulation. In addition, it will briefly discuss re-using…
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A High Reliable Automated Percussive Riveting System for Aircraft Assembly

Shanghai Jiao Tong University-Yunfei Fan, Long Yu, Qingzhen Bi, Yuhan Wang
Shanghai Top NC Tech Co. Ltd.-Yilian Zhang
Published 2019-03-19 by SAE International in United States
Percussive riveting is a widely used way of fastening in the field of aircraft assembly, which used to be done manually. Nowadays, replacing the traditional percussive riveting with automated percussive riveting becomes a trend worldwide, which improves the quality of riveting significantly. For the automated riveting system used in aircraft assembly, reliability is of great importance, deserving to be deeply researched and fully enhanced. In this paper, a high reliable automated percussive riveting system integrated into a dual robot drilling and riveting system is proposed. The riveting system consists of the hammer part and the bucking bar part. And both parts have been optimized to enhance the reliability. In the hammer side, proximity switches are fully used to detect the state of rivet insertion. In the bucking bar side, a reliable step height measurement system is integrated to measure the exposed shank length of the rivet before riveting and the upsetting head height after riveting. Meanwhile, a reliable method is proposed to calibrate the measurement system. By measuring the exposed shank length of the rivet…
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Increasing Development Assurance for System and Software Development with Validation and Verification Using ASSERT™

GE Aviation Systems LLC-Craig McMillan, Mark Stephens, Daniel Russell
GE Global Research Center-Andy Crapo, Michael Durling, Meng Li, Abha Moitra
Published 2019-03-19 by SAE International in United States
System design continues to trend toward increasing complexity as more functionality is added to aviation systems and the level of automation is increased. Since exhaustive validation and verification of this functionality becomes increasingly difficult, reliance on development assurance is needed to provide confidence that errors in requirements, design and implementation have been identified and corrected. To address this need for increased development assurance, GE is introducing a tool called ASSERT™ (Analysis of Semantic Specifications and Efficient generation of Requirements-based Tests). The system developer uses this tool to capture requirements in an unambiguous way with built-in semantic error checking. The requirements analysis engine is then used to assist in requirements validation to identify common problems which may include requirements that conflict with one another, requirements that do not fully specify the behavior of a function, requirements that are not independent of one another, and requirements that are either always true or false. Having unambiguous and complete requirements also enables the tool to consistently generate a complete set of requirements-based test cases and procedures to ensure the…
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