Contributions to the Theories of Topological Groups

The brief abstracts of the papers contained in this thesis are copied from the Bulletin of the American Mathematical Society Abstract (48-1-96) An nth order differential is defined for a function F(x) with arguments and values in topological groups and increments in the central subgroup of the argument space with a relativized topology and a generation postulate. The fundamental theorems on unicity, continuity, linear combinations, and iterative functions are then proved. Abstract (48-5-158) After an abstract calculus of finite differences is defined, functional definitions of a monomial and polynomial for elements of the group as increments are given. The theorem on the homogeneity of a polynomial is proved for central and arbitrary differences; for central differences the difference being a function of the increment alone implies the difference is a monomial; the independence of the central difference of polynomials and the unique decomposition for the abelian valued case are made to depend on the product of a Vandermonde determinant end a finite product of binomial coefficients. The theory is essentially a generalization of the work of Van der Lijn on abstract polynomials in abelian groups. Abstract (50-1-48) By analyzing an example formulated by A. Tychonoff, the spaces Hρ, o less than or equal to ρ less than ∞, are defined in a manner analogous to that £or classical Hilbert space; some basic properties such as linearity, necessary and sufficient conditions for normability, separability, and sufficient conditions for local convexness are proved.</p

The impact of unsteady swirling flow in a single gland labyrinth seal on rotordynamic stability : theory and experiment

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1992.Includes bibliographical references (leaves 219-227).by Knox Taylor Millsaps, Jr.Ph.D

Rotordynamic forces in labyrinth seals: Theory and experiment

A theoretical and experimental investigation of the aerodynamic forces generated by a single gland labyrinth seal executing a simultaneous spinning/whirling motion has been conducted. A lumped parameter model for a single gland seal with coupling to an upstream cavity with leakage is developed along with an appropriate solution technique. From this theory, it is shown that the presence of the upstream cavity can, in some cases, augment the cross-stiffness and direct damping by a factor of four. The parameters that govern the coupling are presented along with predictions on their influence. A simple uncoupled model is used to identify the mechanisms responsible for cross force generation. This reduced system is nondimensionalized and the physical significance of the reduced parameters is discussed. Closed form algebraic formulas are given for some simple limiting cases. It is also shown that the total cross-force predicted by the uncoupled model can be represented as the sum of an ideal component due to an inviscid flow with entry swirl and a viscous part due to the change in swirl created by friction inside the gland. The frequency dependent ideal part is solely responsible for the rotordynamic direct damping. The facility designed and built to measure these frequency dependent forces is described. Experimental data confirm the validity and usefulness of this ideal/viscous decomposition. A method for calculating the damping coefficients based on the force decomposition using only the static measurements is presented. Experimental results supporting the predicted cross force augmentation due to the effect of upstream coupling are presented

Efficiency Improvements of Navy Gas Turbines

Energy Academic Group Science and Technology ProjectGoal: Increase efficiency of gas turbines. Mostly at part power conditions

Autonomous Systems Track

The department of Mechanical and Aerospace Engineering offers an autonomous systems track within the framework of a Master's Degree in Mechanical Engineering. The program can be completed in four to six quarters, depending on academic preparedness of the student, and is developed around several core courses related to modeling and guidance navigation and control algorithms design for autonomous underwater, surface, ground, aerial systems, satellites and spacecraft. Additional course electives can be taken to enhance specialty areas, along with thesis research related to a specific type of an autonomous system or its component, or a wide range of other useful military technologies

Integrated Electric Gas Turbine

PatentAn integrated electric gas turbine comprises a compressor that includes a plurality of airfoils. An electric motor is arranged to drive the compressor, and a combustor is arranged to receive compressed air from the compressor and further arranged to receive a fuel input. A turbine is arranged to receive the combustion gases from the combustor. A generator is integrated with the turbine and arranged to provide a power output. A controller is connected between the generator and the electric motor and arranged to direct a portion of the power output from the generator to the electric motor

Analysis of aero-elastic forces in labyrinth seals and the design of an experimental facility to measure them

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics.Bibliography: leaves 134-138.Knox Taylor Millsaps, Jr.M.S

Fundamental and Applied Biofuels Research at the Naval Postgraduate School (archived)

NPS Defense Energy SeminarFundamental and Applied Biofuels Research at the Naval Postgraduate School, August 28, 201

Combustion Characterization and Ignition Delay Modeling of Low- and High-Cetane Alternative Diesel Fuels in a Marine Diesel Engine

The article of record as published may be found at http://dx.doi.org/10.1021/ef500565tIn support of an ongoing U.S. Navy alternative fuel evaluation program, the combustion characteristics of two very different alternative diesel fuels were evaluated in a direct-injection marine diesel engine across a variety of speeds and loads. The fuels were an algal-based hydrotreated renewable diesel fuel (HRD) with cetane number of ∼75 and a synthetic paraffinic kerosene (SPK) with cetane number of ∼25. These fuels were experimentally tested as blends with conventional petroleumbased military diesel fuel (designated F-76) with cetane ≈ 46, giving a cetane number range from 25 to 75. Start of injection (SOI) was characterized using a strain gauge to determine actuation of the mechanical unit injector; SOI remained essentially unchanged for changes in fuel type. As expected based on cetane number, ignition delay (IGD) increased with greater amounts of SPK fuel and decreased for greater amounts of HRD fuel in the test blend. Energy release analysis showed that longer IGD led consistently to slightly advanced combustion phasing, as indicated by the location of 50% mass fraction burned, decreased overall combustion duration, and greater maximum rate of pressure rise due to greater fuel-air premixing. Fuel consumption was 0−5% higher for these alternative fuels. Ignition delay was modeled using a detailed primary reference fuel mechanism tuned to match the measured cetane number of each neat and blended fuel. The modeled chemistry was able to capture relative changes in the experimentally observed IGD, suggesting that the measured differences in physical properties, which will affect spray development, do not contribute as significantly to differences in IGD. The results suggest that typical higher cetane alternative fuels, such as HRD, have no deleterious effects from the perspective of combustion characteristics. Processes that yield lower cetane alternative fuels, such as SPK, while still achieving satisfactory performance, begin to show signs of problems through delayed combustion, increased rates of pressure rise, and higher peak pressures, which induce higher mechanical stress and combustion noise.Office of Naval Research as part of the Alternate Naval Fuels Program (N0001413WX20922)Office of Naval Research as part of the Alternate Naval Fuels Program (N0001413WX20922

Fundamental and Applied Biofuels Research at the Naval Postgraduate School (flyer)

Defense Energy SeminarWith Guest Lecturers Dr. Knox Millsaps & Dr. Chris Brophy Department of Mechanical & Aerospace Engineering, Naval Postgraduate School Dr. Knox Millsaps Professor, Chairman, & Director, Marine Propulsion Laboratory Dr. Chris Brophy Associate Professor & Director, Rocket Propulsion & Combustion Laboratory This talk will provide a broad overview of the history and development of synthetic and bioderived liquid fuels, their potential uses in naval ship and aircraft, as well as a survey of some of the research that has been conducted by NPS faculty and thesis students on biofuels and advanced energy systems over the past 3 years, such as..