Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 15 of 15 for “"microengine"”.
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Packaging of the MIT Microengine
The MIT Microengine Project is an on-going effort to build a MEMS based gas turbine engine and turbo generator. This thesis covers the development and testing of the packaging needed for the microengine and related devices. The packaging of the microengine includes the fluidic, electrical, and …
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Rotor speed microsensor for the MIT Microengine
… the MIT MEMS micro gas turbine engine. The MIT microengine is a gas combustion engine made by micromachining and bonding six silicon wafers. The sensor is a boron-doped polysilicon resistor with a serpentine geometry that is thermally isolated from the substrate. The sensor is designed to …
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A MEMS valve for the MIT Microengine
… temperature or low pressure applications. The microengine prototype valve comprises of three fusion-bonded SOI wafers. Electrostatic- actuation is used to lift the silicon boss actuator supported on four L-shaped tethers and open against high pressure. Polysilicon is chosen as the seat material …
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Silicon carbide process development for microengine applications : residual stress control and microfabrication
The high power densities expected for the MIT microengine (silicon MEMS-based micro-gas turbine generator) require the turbine and compressor spool to rotate at a very high speed at elevated temperatures (1300 to 1700 K). However, the thermal softening of silicon (Si) at temperatures above 900 K …
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Hybrid silicon/silicon carbide microstructures and silicon bond strength tests for the MIT Microengine
… the operating envelope of the first generation microengine, and second, a testing technique to measure the toughness of silicon to silicon fusion bonds. Due to the relatively low strength of Si at high temperatures, the all-silicon demonstration device does not yet meet the design …
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An assessment of the aerodynamic, thermodynamic, and manufacturing issues for the design, development, and microfabrication of a demonstration micro engine
… for power conversion. Micro gas turbine engines (microengines) are one particular application of this technology. These tiny jet engines have immediate application as propulsion systems for Micro UAVs Other envisioned applications include portable electrical power generation for commercial, …
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Dynamical system modeling of a micro gas turbine engine
… a simulation platform for predicting the microengine performance and control design, as well as giving an estimate of the microengine behavior under current design. The thesis first analyzes and models the dynamical components of the microengine. Then a nonlinear model, a linearized model, …
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Microfabricated refractory ceramic structures for micro turbomachinery
The MIT Microengine Project was initiated in 1995 as a joint effort between the Gas Turbine Laboratory (GTL) and Microsystems Technology Laboratory (MTL) to develop a MEMS-based micro-gas turbine engine. The thermodynamic requirements of power-generating turbomachinery drive the design towards high …
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Fabrication of ceramic and ceramic composite microcomponents using soft lithography
… for mass production, and to meet the needs of microengine application. A group of new processes have been developed and the results are characterized for fabrication of high precision ceramic oxides and composite microcomponents using soft lithography and colloidal powder processing. The …
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Materials characterization and structural design of ceramic micro turbomachinery
… to the differences in length scales between the microengine and conventional macroscale turbomachinery, a detailed investigation of the effect of length scale has been conducted. This shows that a direct comparison of a microengine structural design with that embodied in microscale engines is …
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Analysis of DRIE uniformity for microelectromechanical systems
… is validated by using a mask layer from the MIT Microengine project as a demonstration layout. The model can be tuned to predict the etch behavior to an accuracy of 0.1% RMS normalized error. Furthermore, a feature level model, which considers the effects of sidewall loading on the depletion of …
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Development of a liquid-fueled micro-combustor
… advantages for military applications. Thus, a microengine burning JP8 fuel is attractive as a portable power source and potential replacement for batteries. The thesis first presents a number of models developed to design the fuel vaporizer, the fuel-air mixing chamber, and the combustion …
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Design, fabrication, experimentation and analysis of high-speed microscale gas bearings
Microengine Program. The all-silicon device consist of a free-rotating microturbine, with 4.2 mm rotor diameter, enclosed within a five wafer fusion-bonded stack. Of note are the low aspect ratio journal bearing and large journal bearing clearances, primarily limited by microfabrication, from which …
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Development of a high power density combustion system for a silicon micro gas turbine engine
… of the complete hot flow path of a multi-level microengine. The 0.195 cm 3 combustion chamber has been tested for several tens of hours and is shown to sustain stable hydrogen combustion with exit gas temperatures above 1600K and combustor efficiencies as high as 95%. The structure also serves …
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Experimental Investigation and Modeling of Scale Effects in Micro Jet Pumps
<p>Since the mid-1990s there has been an active effort to develop hydrocarbon-fueled power generation and propulsion systems on the scale of centimeters or smaller. This effort led to the creation and expansion of a field of research focused around the design and reduction to practice of Power MEMS …