An improved turbine disk design to increase reliability of aircraft jet engines

An analytical study was performed on a novel disk design to replace the existing high-pressure turbine, stage 1 disk on the CF6-50 turbofan engine. Preliminary studies were conducted on seven candidate disk design concepts. An integral multidisk design with bore entry of the turbine blade cooling air was selected as the improved disk design. This disk has the unique feature of being redundant such that if one portion of the disk would fail, the remaining portion would prevent the release of large disk fragments from the turbine system. Low cycle fatigue lives, initial defect propagation lives, burst speed, and the kinetic energies of probable disk fragment configurations were calculated, and comparisons were made with the existing disk, both in its current material, IN 718, and with the substitution of an advanced alloy, Rene 95. The design for redundancy approach which necessitated the addition of approximately 44.5 kg (98 lb) to the design disk substantially improved the life of the disk. The life to crack initiation was increased from 30,000 cycles to more than 100,000 cycles. The cycles to failure from initial defect propagation were increased from 380 cycles to 1564 cycles. Burst speed was increased from 126 percent overspeed to 149 percent overspeed. Additionally, the maximum fragment energies associated with a failure were decreased by an order of magnitude

Notes on the 1966 Summer Study Program in Geophysical Fluid Dynamics at the Woods Hole Oceanographic Institution

Originally issued as Reference No. 66-46, series later renamed WHOI-.The lecturers, Drs. Howard, Stern and Veronis, have introduced the participants to several aspects of geophysical fluid dynamics at the frontiers of current research. Their choice of topic and its development was to serve, on one hand, a pedagogic function and, on the other, to suggest a variety of allied unsolved problems.National Science Foundatio

1992 NASA/ASEE Summer Faculty Fellowship Program

For the 28th consecutive year, a NASA/ASEE Summer Faculty Fellowship Program was conducted at the Marshall Space Flight Center (MSFC). The program was conducted by the University of Alabama and MSFC during the period June 1, 1992 through August 7, 1992. Operated under the auspices of the American Society for Engineering Education, the MSFC program, was well as those at other centers, was sponsored by the Office of Educational Affairs, NASA Headquarters, Washington, DC. The basic objectives of the programs, which are the 29th year of operation nationally, are (1) to further the professional knowledge of qualified engineering and science faculty members; (2) to stimulate and exchange ideas between participants and NASA; (3) to enrich and refresh the research and teaching activities of the participants' institutions; and (4) to contribute to the research objectives of the NASA centers

A compendium of computational fluid dynamics at the Langley Research Center

Through numerous summary examples, the scope and general nature of the computational fluid dynamics (CFD) effort at Langley is identified. These summaries will help inform researchers in CFD and line management at Langley of the overall effort. In addition to the inhouse efforts, out of house CFD work supported by Langley through industrial contracts and university grants are included. Researchers were encouraged to include summaries of work in preliminary and tentative states of development as well as current research approaching definitive results

Electromagnetic Energy Transport Through Complex Media

Electromagnetic waves are used in two distinct ways, to transmit information and to carry energy. For aerospace applications, the use of optical methods is excellent for making high fidelity measurements. High temperature flows, such as those found during atmoshperic entry, can also experience significant radiative heat transfer. This energy can lead to added heat loads to vehicles and, in extreme cases, alter the flow chemistry. Radiative transfer can also be affected by the addition of particulate material in the flow. These particles can form optically thick clouds which dramatically affect the flow properties through the process of absorption and scattering. This work is divided into two principal parts. The first part analyzes the various aspects of radiative transfer in a heated particle laden flow. This includes a summary of methods used to estimate the optical properties of individual particles, as well as the developments to calculate the optical properties of large absorbing particles. This is followed by an analysis of radiative transfer through groups of particles. It is found that the Beer Law can suffer inaccuracies at high particle densities or very fine mesh resolutions. These results are used to develop a Monte Carlo ray tracing (MCRT) framework to analyze the radiative transfer through a particle laden flow, and validate coupled simulations of the system. The second part of this work discusses hydrogen helium flows at atmospheric entry conditions experienced in the outer gas giants. A non-Boltzmann method to estimate excited states is developed. This is used to analyze chemical models used for computational fluid dynamics (CFD) simulations of these flows and validate them against experimental measurements. It is found that no current CFD chemistry models accurately predict the flow chemistry, likely due to discrepancies in the ionization rate of hydrogen.PHDAerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169630/1/khansson_1.pd

Ames Research Center publications: A continuing bibliography, 1978

This bibliography lists formal NASA publications, journal articles, books, chapters of books, patents and contractor reports issued by Ames Research Center which were indexed by Scientific and Technical Aerospace Abstracts, Limited Scientific and Technical Aerospace Abstracts, and International Aerospace Abstracts in 1978. Citations are arranged by directorate, type of publication and NASA accession numbers. Subject, personal author, corporate source, contract number, and report/accession number indexes are provided

Aeronautical engineerng: A special bibliography with indexes, supplement 36

This special bibliography lists 628 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1973

Aeronautical engineering: A continuing bibliography with indexes (supplement 240)

This bibliography lists 629 reports, articles, and other documents introduced into the NASA scientific and technical information system in May, 1989. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Multidisciplinary Study of Soft Shape Morphing Systems

Nature abounds with examples of shape morphing systems where an entity either gradually grows into a complex 3-D shape pattern or rapidly morphs into a new configuration. Inspired by the shape shifting capabilities of biological systems, in this work we study the response of natural and synthetic morphing systems through a few examples. These include the in vitro adaptive contraction of a cardiac muscle cell inside a constraining hydrogel, inflation of architectured rubber membranes, and a shape morphing soft robot. Cardiac muscle cells (cardiomyocytes), have an intrinsic mechano-chemo-transduction (MCT) mechanism that enable them to automatically convert mechanical loads into biochemical signals to actively regulate their amplitude and speed of contraction. At the molecular level, this is attributed to the morphing of regulatory and motor proteins (actin and myosin filaments) to facilitate muscle contraction. The underlying MCT mechanisms, however, are unclear and currently under investigation. To help decipher these mechanisms, we develop a mathematical model, as a companion tool for the experimental in vitro Cell-in-Gel system of our collaborators, to analyze the time-dependent, 3-D strains and stresses within a cardiomyocyte contracting in a viscoelastic medium. The model utilizes the exact analytical solution of the viscoelastic Eshelby inclusion boundary value problem as an efficient computational tool to simulate the mechanical fields inside and outside the cardiomyocyte. In a second study, we investigate the inflation of shape morphing synthetic soft composites with architectured geometry and material properties. Such shape morphing systems could have desirable applications in space deployable systems where there is a growing demand for energy-efficient lightweight and low-cost structures. These structures possess an exceptionally high mechanical packaging efficiency and very small stowage volume, which makes them attractive candidates for space applications including antenna reflectors, solar arrays, inflatable rovers, re-entry equipment, and human habitats. In particular, we explore several feasible 3-D shapes that can be achieved through the inflation of an initially flat rubber membrane with nonuniform geometrical and material properties. Our rubber-based prototypes provide a convenient basis for conceptual scientific and design explorations in shape morphing inflatable structures. In a third study, we explore the idea of shape shifting in the design and fabrication of synthetic soft robots with active components. Motivated by the swimming mechanisms of jellyfish, we develop a novel concept for a soft biomimetic underwater robot that imitates the shape and kinematics of the typical animal. The robot swims by harnessing the buckling instability of its soft body to quickly morph from an initially flat into a deformed dome-shaped configuration, which generates the required thrust for underwater locomotion. Joule heating of an embedded pre-stretched shape memory alloy spring, serves as an artificial muscle for the robot to make this shape morphing possible. The proposed synthetic shape morphing system introduces a new idea in design of simple, compact, and biomimetic robots with smart artificial muscles.PHDAerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/168099/1/mkazemi_2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168099/2/mkazemi_1.pd