Pal D.,United Technologies Aerospace Systems |
Feng F.,United Technologies Aerospace Systems
SAE Technical Papers | Year: 2016
In 3-phase AC application, there is additional heat dissipation due to skin effects and proximity effects in bus bars. In addition, when the 3- phase AC is used to drive a motor at high fundamental frequency, for example between 666 Hz and 1450 Hz, there are higher bus bar losses due to presence of higher frequency harmonic content. High frequency current carrying bus bars in aircraft power panels are typically cooled by natural convection and radiation. In this paper a thermal and electrical finite element analysis (FEA) is done for a bus bar system. For electrical loss modeling, 3D electromagnetic FEA is used to characterize losses in three parallel bus bars carrying AC at various frequencies. This loss analysis provides correlation of heat loss as function of frequency. A method is presented where this AC loss is incorporated using computational fluid dynamics (CFD) based thermal model. Material resistivity is artificially adjusted to account for skin and proximity effects. Thermal analysis results are then compared to determine net effect of the AC skin, proximity and higher frequency harmonics on bus bar temperatures. Thermal analysis is done using CFD tool such as ICEPAK. Modeling of bus bar uses Joule heating method where the heat dissipation in bus bar is computed by analysis based on current, specified resistivity, temperature coefficient of bus bar material, geometry of bus bar and temperature. © Copyright 2016 SAE International.
Luko S.N.,United Technologies Aerospace Systems |
Neubauer D.V.,Corning Inc.
Standardization News | Year: 2015
Multiple inspections at different locations or at different points are a consideration with inspection redundancy. Where multiple inspection systems are used, and redundancy with each system is possible, it is generally best to allocate inspection redundancy resources in inverse proportion to the probability of detection for each system. That is, the lower the discovery probability the greater the number of redundant inspections that should be used.
Luko S.N.,United Technologies Aerospace Systems |
Neubauer D.V.,Corning Inc.
Standardization News | Year: 2014
The article concerns prediction intervals for the next observation when users have a set of data and their data is of the attribute type. The intervals presented are approximate and are based on an approximating normal distribution. They should be useful for most cases where the initial sample observation is at least five events for the binomial case, and 10-15 or more for the Poisson case. A quality metric for a certain operation in a large firm is to measure the number of rejected material lots received by the firm's receiving inspection operation. This information is measured and reported to management on a monthly basis. For the Poisson distribution, observations are made on an inspection region that can be based on time, area, space, number of objects or some other region description. The number of events users observe can be any whole number at least zero.
Neubauer D.V.,Corning Inc. |
Luko S.N.,United Technologies Aerospace Systems
Quality Engineering | Year: 2012
In this first part of a two-part series, common attribute sampling standards are discussed and compared. Military standard 105 (MIL-STD-105) is the premier attribute sampling standard that has led to a number of derivative standards in recent decades that are discussed here. While these standards share a lot of common ground, there are some differences among them. While military standards, such as MIL-STD-105, are no longer supported by the U.S. Department of Defense, there are many comparable standards to use which are supported by various standards organizations. In this paper, the reader will be introduced to these derivative standards and how they compare to each other and to MIL-STD-105. In the second part of this series, MIL-STD-414 and its derivative standards will be discussed for the inspection of variables data. Their ties to MIL-STD-105E and its derivatives will also be used to tie together all the standards in this article as well. © 2013 Taylor & Francis Group, LLC.
News Article | February 28, 2017
HARTSVILLE, S.C., Feb. 28, 2017 (GLOBE NEWSWIRE) -- Sonoco (NYSE:SON), one of the largest diversified global packaging companies, today announced that Julie Albrecht will join the Company as Corporate Vice President, Treasurer/Assistant Chief Financial Officer, according to Barry Saunders, senior vice president and chief financial officer. A photo accompanying this announcement is available at http://www.globenewswire.com/NewsRoom/AttachmentNg/a749d455-21dd-4e28-9095-d2a6feda1714 Albrecht spent nearly 20 years at Goodrich Corporation/United Technologies Aerospace Systems, progressing through several finance positions including the Assistant Treasurer position for the $7 billion corporation. In 2012, Goodrich Corporation was acquired by United Technologies, and Albrecht became Finance Director of an $800 million business unit, where she led a team with responsibility over eight global facilities. During this time, Albrecht also led Financial Planning & Analysis for a $3.5 billion aftermarket business. Most recently, she was Vice President, Finance, Investor Relations and Treasurer for Esterline Technologies Corporation in Bellevue, Washington. “Julie comes to Sonoco with vast knowledge of finance and treasury,” said Saunders. “A solutions-oriented leader, her international experience and strategic vision will enable Sonoco to continue to grow its global presence in the packaging industry.” Albrecht began her career in public accounting with PricewaterhouseCoopers after graduating from Wake Forest University with a BS in Accounting with honors. About Sonoco Founded in 1899, Sonoco is a global provider of a variety of consumer packaging, industrial products, protective packaging and display and packaging supply chain services. With annualized net sales of approximately $4.8 billion, the Company has 20,000 employees working in more than 300 facilities in 33 countries, serving many of the world’s best known brands in some 85 nations. For more information on the Company, visit our website at www.sonoco.com.
Reddy K.R.,Iowa State University |
Ryon J.A.,United Technologies Aerospace Systems |
Durbin P.A.,Iowa State University
International Journal of Heat and Fluid Flow | Year: 2014
The current work develops a variant of delayed detached eddy simulation (DDES) that could be characterized as limiting the production term. Previous formulations have been based on limiting the dissipation rate ( Spalart et al., 2006). A clipped length scale is applied directly to the eddy viscosity, yielding a Smagorinsky-like formulation when the model is on the eddy simulation branch. That clipped eddy viscosity limits the production rate. The length scale is modified in order to account for the log-layer mismatch (a well-known issue with DDES), without using additional blending functions. Another view of our approach is that the subgrid eddy-viscosity is represented by a mixing length formula l2ω in the eddy field ω acts like a filtered rate of strain. Our model is validated for channel flow as well as separated flows (backward-facing step, 2D periodic hills) and illustrated via an air-blast atomizer. © 2014 Elsevier Inc.
Dolan B.,University of Cincinnati |
Gomez R.V.,University of Cincinnati |
Zink G.,United Technologies Aerospace Systems |
Pack S.,United Technologies Aerospace Systems |
Gutmark E.,University of Cincinnati
AIAA Journal | Year: 2016
Nitrous-oxide emissions and the equivalence ratio resulting in lean extinction of two adjacent gas turbine fuel/air nozzles are measured as the spacing between the two nozzles is varied. Two swirl-stabilized nozzle types are tested: a high-stability pilot design, and a low-emission design with a much lower swirl number. Jet A is used as the fuel. The lean blowout point is tested for both nozzle types at each spacing. Increased spacing results in blowout at a lower equivalence ratio, which is likely due to increased air velocity between the nozzles that occurs at closer spacings. The spacing has a dramatic effect on the nitrous-oxide emissions index (grams of nitrous-oxide produced per kilogram of fuel burned) for the three possible nozzle combinations. The nitrous-oxide index emissions are greatest when two nozzles are placed close, and they decrease as the internozzle distance grows. The excited hydroxyl radical (OH)∗ chemiluminescence imaging shows how the OH∗ intensity is greater on the side of the nozzles toward the neighboring flame. This is an indication that the heat release rate and/or temperature is raised in part of the flame due to the adjacent nozzle. The magnitude of the effects of nozzle spacing, both on emissions and lean blowout, are dependent on the nozzle design. Asymmetries in the flow and flame structure of the two nozzles appear when using two high-swirl pilot nozzles at larger nozzle spacings. This disturbs the emissions trend and causes an increase in nitrous-oxide production for this case. © 2015 by Brian Dolan. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Copies of this paper may be made for.
Luko S.N.,United Technologies Aerospace Systems
Standardization News | Year: 2012
Stephen N. Luko explains the concept of standard error and ways to measure a random error in a reported statistic. ASTM E2586, Practice for Calculating and Using Basic Statistics, defines standard error as 'The standard deviation of the population of values of a sample statistic in repeated sampling, or an estimate of it'. Standard error measures random error in a reported statistic, the kind of error due to random sampling variation in repeating a test under the same conditions. The error in a reported result is called sampling error, and this is measured as an absolute deviation from the unknown true value. One of the most commonly used statistics is a simple proportion. There is a sample of objects size n, and each object is observed for the occurrence of an attribute.
Stapleton T.J.,United Technologies Aerospace Systems |
Baccus S.,NASA |
Broyan Jr. J.L.,NASA
43rd International Conference on Environmental Systems | Year: 2013
NASA is working with a number of commercial companies to develop the next low Earth orbit spacecraft. The hardware volume and weight constraints are similar to or greater than those of the Apollo era. This, coupled with the equally demanding cost challenge of the proposed commercial vehicles, causes much of the Environmental Control and Life Support System (ECLSS) designs to be reconsidered. The Waste Collection System (WCS) is within this group of ECLSS hardware. The development to support this new initiative is discussed within. A WCS concept - intended to be common for all the Low Earth Orbit and Deep Space vehicle platforms currently on the drawing board - is being developed. The new concept, referred to as the Universal Waste Management System (UWMS), includes favorable features from previous designs while improving on other areas on previous Space Shuttle and the existing International Space Station (ISS) WCS hardware, as needed. The intent is to build a commode that requires less crew time, improved cleanliness, and a 75% reduction in volume and weight compared to the previous US ISS/Extended Duration Orbitor WCS developed in the 1990s. The UWMS is most similar to the ISS Development Test Objective (DTO) WCS design. It is understood that the most dramatic cost reduction opportunity occurs at the beginning of the design process. To realize this opportunity, the cost of each similar component between the UWMS and the DTO WCS was determined. The comparison outlined the design changes that would result in the greatest impact. The changes resulted in simplifying the approach or eliminating components completely. This initial UWMS paper will describe the system layout approach and a few key features of major components. Future papers will describe the UWMS functionality, test results, and components as they are developed.
Silva-Martinez J.,NASA |
Martinez V.,United Technologies Aerospace Systems
Proceedings of the International Astronautical Congress, IAC | Year: 2015
One of the challenges for long-duration crewed missions to deep space is the use of advanced computer tools. We first need a thorough understanding of how to successfully incorporate these in current processes that support the design and actual built of projects here on Earth that will be sent to space. This study will use as an example the implementation of advanced computer-based tools to the traditional pen and paper redlined process. A redline process is used in aerospace companies to reflect any changes made to a document. The effectiveness of proposed computer-based tools and their interaction with the user will be explored. It is necessary to understand the challenges and scientific processes that come with the integration of both the user and complex systems such as computer-based tools as new release methods for redlined procedures. Typically these types of tools use a universal design that allows accessibility by everyone, but making these tools too general may lose the user-oriented idea. A major challenge is to create safe systems that are easy for the user to understand and operate; this means a system that incorporates a human-centric design process. Methods that can quickly be processed through human's perceptual system and expand our working memory and information storage will be explored, such as the influence of different organizational factors in employees' behavior, actions, and job performance. Personnel and products safety as well as the effectiveness of our performance may depend on several of those organizational factors, yet many times they are not taken into account. For example, when organizational changes are made to departments or procedures without clearly having communicated to the teams can result in significant mishaps. We will see how the cognitive processing of decision making for human-machine interaction through the practices used in aviation psychology and crew resource management can help minimize human errors in the aerospace realm. The correct integration of advanced computer-based tools with the abilities and limitations of humans will be helpful for earlier detection and better management of errors during the design and built of space programs here on Earth. Once that process is well understood and established we will be able to apply it in future human missions into deep space. Copyright © 2015 by the International Astronautical Federation.