Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2005. / Includes bibliographical references (p. 111-112). / A unique counter-rotating aspirated compressor was tested in a blowdown facility at the Gas Turbine Laboratory at MIT. The facility expanded on experience from previous blowdown turbine and blowdown compressor experiments. Advances in thermocouple and facility designs enabled efficiency estimates through total temperature and total pressure measurements. The facility was designed to provide at least 100 ms of available test time, approximately a factor of five greater than previous blowdown compressor facilities. The adiabatic core efficiency of the compressor was estimated with an uncertainty of 0.8% and the corrected flow was estimated with an uncertainty of 1.0%. The compressor was tested at several operating conditions and two speed lines were partially mapped. The maximum measured total pressure ratio across the two stages was 3.02 to 1. The measured adiabatic efficiency for that point was 0.885. The span-wise total pressure, total temperature, and efficiency profiles were compared to the predicted profiles for runs with the corrected speeds of the two rotors at 90% of design and 100% design. There appears to be reasonable agreement between the predictions and the measurements. / by David V. Parker. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2006. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Includes bibliographical references (p. 185-201). / Carbon nanotubes' (CNTs) superlative combination of electrical, thermal, and especially mechanical properties make them ideal candidates for composite reinforcement. Nanocomposites and hybrid composite architectures employing traditional advanced composites and CNTs offer significant potential mechanical and multifunctional performance benefits. CNT/polymer composites and two different hybrid architectures are experimentally investigated in this work. A novel process for rapidly growing dense, long, high-quality aligned CNT forests is employed. The first architecture is comprised of aligned fibers with CNTs grown radially on their surface. For the second architecture, dense forests of vertically aligned CNTs are placed between the plies of a laminate, in the through-thickness direction. Fundamental issues related to realizing hybrid composite architectures are investigated experimentally: wetting of the CNTs by commercially available polymers for the different architectures, effective reinforcement of the polymer matrices due to the addition of CNTs, and retention of mechanical (stiffness and strength) properties of the fibers after the CNT growth process. / (cont.) Wetting of CNT forests by several commercial polymers (including a highly-viscous epoxy) is demonstrated at rates conducive to creating a fully-dispersed CNT/matrix region for the two hybrid architectures previously described. Direct measurements of the mechanical properties of nanocomposites are reported for the first time in the literature. Increases in the Young's modulus of the polymer as high as 220% with just 2% volume fraction of aligned CNTs are observed. Equivalent reinforcement had been obtained previously by other authors with 5% volume fraction of randomly oriented CNTs. Single-fiber tension tests indicate no mechanical degradation (stiffness and strength) for alumina fibers undergoing the CNT growth process. Preliminary results on the fabrication of the two hybrid architectures are also presented. All the experimental results presented in this work indicate that hybrid CNT/composite architectures are feasible and future work focuses on mechanical and multifunctional property characterization of these and other hybrid architectures, and scaling to a continuous CNT growth process. / by Enrique J. García. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991. / Includes bibliographical references (leaves 127-128). / by Kurt D. Eberly. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1997. / Includes bibliographical references (leaves 152-154). / by Duncan P. Reijnen. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995. / by Kevin Sung-ho Lee. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991. / Includes bibliographical references (p. 145-150). / by Petros G. Voulgaris. / Ph.D.

Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 133-135). / This thesis describes experimental assessments of the aerodynamic boundary layer ingestion (BLI) benefit of the D8 advanced civil aircraft design. Two independent methods were applied for 1:11 scale (4.1 m wingspan) powered aircraft model experiments in the NASA Langley 14x22-foot Subsonic Wind Tunnel. The metric used as a surrogate for fuel consumption was the input mechanical flow power, and the benefit was quantified by back-to-back comparison of non-BLI (podded) and BLI (integrated) configurations. The first method (indirect) was the estimate of mechanical flow power based on the measured electrical power to the propulsors, plus supporting experiments to characterize the efficiencies of the fans and the electric motors that drive them, at the MIT Gas Turbine Laboratory. The second method (direct) was the direct integration of flowfield measurements, from five-hole probe surveys at the inlet and exit of the propulsors, which provided flow angles, velocity components, and pressure coefficients. Data were taken at different wind tunnel speeds, and conditions to determine overall performance dependence on non-dimensional power and angle of attack. At the simulated cruise point, the first method gave a measured aerodynamic BLI benefit of 7.9% +/- 1.5% at 70 mph tunnel velocity, and 8.5% +/- 1.5% at 84 mph, and the second method gave a measured benefit of 8.1% +/- 3.3% at 70 mph, and 12.2% +/- 3.4% at 84 mph. For the aircraft models examined, the aerodynamic benefit was found to come primarily from a decrease in the propulsor jet velocity (increase in propulsive efficiency) and thus a decreased jet dissipation, with the contribution from decreased wake and airframe dissipation being roughly an order of magnitude smaller. / by Cécile J. Casses. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1998. / Includes bibliographical references (p. 123). / by Alex Yen Hung Lee. / M.S.

Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2014. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 109-113). / Ion electrospray propulsion devices rely on the transportation of ionic liquid propellant to emission regions where ions are extracted at high velocities. One such method involves the use of porous substrates to passively transport propellant towards conically shaped features of the same porous material. Historically, the methods of fabricating such small features (~150[mu]m tapered to ~20[mu]m over a height of ~150[mu]m) are subtractive, in that material is selectively removed from a substrate to reveal the desired features. The limitations of these processes include but are not limited to: process repeatability, complex operation, material selection limited by the process, serial operation, and long/expensive fabrication time. With an understanding of these limitations, the goal of this research is to explore new materials and processes to identify candidates for electrospray propulsion applications. In particular, processes that allow for additive tip manufacturing, parallel processing, and uniformity in addition to materials that allow for variable and uniform porosity have been studied. As part of this research, the sol-gel and freeze casting methods for producing porous materials were characterized to better identify feasibility for electrospray propulsion. Characterization includes the feasibility of molding porous tips directly onto substrates. As a result of this research, porous substrates from different materials and varying pore sizes were fabricated via both methods. A porous emitter tip prepared by the sol-gel method was fired and shown to extract current at levels exceeding the state of the art. Finally, a new process, entitled sol freeze, was invented that utilizes the benefits of both the sol-gel and freeze casting methods. Additionally, porous material research for the purpose of contact electrodes was investigated. In order to lengthen the electrochemical window during electrospray thruster firing, a desire for conductive porous materials with large internal surface area was discovered. Carbon xerogel electrodes with embedded wires were designed and fabricated through this research. Specifically, carbon xerogel electrodes with internal surface areas on the order of 500 m² /g were fabricated and tested. / by Steven Mark Arestie. / S.M.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1984. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERO. / Includes bibliographical references. / by Peter Frederick Lorber. / Ph.D.