Search results

Title: MINIATURE SHOCK TUBE ACTUATORS FOR HIGH SPEED FLOW CONTROL APPLICATIONS
Creator: Ramachandran, Rakesh Chandran
Date: 2011-04-11, 2011-05
Description: In the field of aero-acoustics, one of the primary areas of interest has always been centered around the resonant flows. The fluid structure...
Show moreIn the field of aero-acoustics, one of the primary areas of interest has always been centered around the resonant flows. The fluid structure interactions gives rise to a reverberant field, which results in high amplitude fluctuating pressures associated with the resonant tones that could lead to sonic fatigue failure of sensitive components in the vicinity of such flows. One such fluid structure interaction is the cavity flow problem. Several flow control technologies exist to suppress cavity tones but most of them lose efficacy at off-design conditions and particularly at higher subsonic and supersonic flows. It is due to this fact that there is a high demand for high control authority flow control actuators. In order for an actuator to have higher control authority, one must be able to use a mechanism that has sufficient energy to disrupt the cavity tone generation mechanism at higher subsonic Mach numbers. One such mechanism is the shock tube generating high strength shock waves. To the best of our knowledge, there does not appear to be any use of shock waves to suppress noise emitted by cavity in aircrafts. The main challenge lied in developing the miniature shock tubes that could produce high intensity shock waves. In the present work, we designed, developed and tested these miniature shock tube flow control actuators. The initial part of this work involved a detailed study of the theory behind producing shock waves using a shock tube. The designing and development part included a lot of trial and error adjustments to produce shock waves as predicted by the 1D shock wave theory. Two shock tube actuators were developed, one having a single shock tube and another with three shock tubes but with the same exit area as the previous one. We carried out various characterization experiments measuring the unsteady pressure at the exit of these shock tubes and also the walls of the shock tube. The experimental investigation of the shock tubes revealed that miniature version of the shock tubes indeed produced high intensity shock waves as predicted by the shock wave theory. Apart from the shock tube actuators, fast acting solenoid valves which does not produce any shock were also tested, to compare the efficacy of both types of actuators. The later part of the work focuses on the actual application of these actuators as flow control devices. First, we delve into the acoustic suppression results which show the amount of tonal noise suppression achieved by using these actuators. For the M = 0.6 case the valves produced very good suppression up to 20 dB but the mass flow rate of these valves were about 26% of the main jet mass flow rate. In the M = 0.8 flows the valves produced negligible suppression. The multiple shock tube performed better than the single shock tube in both cases with a tonal noise suppression of up to 12 dB and 10 dB for M = 0.6 and M = 0.8 flows, respectively. The effect of the shock wave on the cavity tone was evident from the results and had a memory effect on the cavity tone suppression. Due to this the mass flux and the momentum coefficient for the shock tube actuators were considerably low. In order to better understand the mechanism through which the actuators suppress cavity tones, mean velocity measurements and phase averaged pressure measurements were carried out. Based on these results, it was observed that the lifting of the shear layer was the dominant mechanism behind steady and pulsed mass injection. In addition to this beamforming, used for locating the noise sources, was also used to study the cavity tones. Detailed discussion of the results are presented in this report.
M.S. in Mechanical and Aerospace Engineering, May 2011
Show less

Title: Motive power and distribution charges of a packing plant
Creator: Waldemar Sir, Walter
Date: 2009, 1918
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/motivepowerdistr00wald
Thesis (B.S.)--Armour Institute of Technology

Title: INVESTIGATION OF BI-IN-SN AND BI-IN-SN-GA AS PHASE CHANGE MATERIALS
Creator: Huynh, Hong Trang
Date: 2012-05-02, 2012-07
Description: Phase change energy storage is one of the most effective ways to store thermal energy. The difference between metallic phase change materials ...
Show morePhase change energy storage is one of the most effective ways to store thermal energy. The difference between metallic phase change materials (PCMs) and organic and inorganic PCMs is discussed. Bi-In-Sn and Bi-In-Sn-Ga alloys with near eutectic compositions were analyzed using DSC, X-Ray, EDS and metallography to establish the alloy properties. An attempt was made to package the alloy in metallic and non-metallic foams and various tests such as infiltration and cycling tests were conducted to test the feasibility of various containment materials. These PCM alloys were applied in a prototype cooling system of electronic devices for better heat dissipation than conventional heat sinks. Tests were conducted to measure the effectiveness of the alloys. Different designs were suggested for the containment of the alloy.
M.S. in Mechanical, Materials, and Aerospace Engineering, July 2012
Show less

Title: Computing transition and flow development in turbulent channel flows
Creator: Sallot, Thomas
Date: 2012-12-05, 2012-12
Description: A zero pressure gradient (ZPG) boundary layer in a wind-tunnel test section was computed using two-dimensional CFD simulations utilizing two...
Show moreA zero pressure gradient (ZPG) boundary layer in a wind-tunnel test section was computed using two-dimensional CFD simulations utilizing two RANS models, Spalart-Allmaras (SA) and k􀀀! (SST), and two di erent software suites; i.e., Fluent and STAR-CCM+. These computations have been compared and they revealed that the SST model yields better agreement with experimental data than the SA. They also demonstrate that STAR-CCM+ has very little sensitivity to small pressure gradients, and that is why its computation for the ZPG are not exactly matching the reference data (experiment and DNS). Further analysis of the two softwares leads to the conclusion that the transition is dealt with di erently. These di erent approaches can also contribute to the discrepancies observed in the results. The second part of this study is aimed at analyzing the SA model and proposing an approach to improve its results. Tests on the various options proposed in STAR-CCM+ led us to understand how crucial it is to know the e ect of each setup. In addition, several DNS pro les have been used as in ow conditions for the ZPG problem in order to show that this model can be signi cantly improved by using the appropriate in ow conditions past the transition of the boundary layer. Alternatively, incorporating a transition model into the SA computations based on an approach like the en model, or more advanced transition codes, can result in much better agreement with experiments and recent DNS results. The third part of this work is focused on one of the most computed ows in turbulence: the channel ow. The rst goal was to con rm that an implementation of transition similar to that in the ZPG case can be e ectively used for the channel. The second focus was to nd a criterion to establish the required fetch for the fully developed region in a channel. The criterion found here is based on the asymptotic trend of the centerline velocity and its result indicates a longer distance than the usual xi 100 to 150 full channel heights found in the literature, especially at low Reynolds numbers. Finally, this study reveals the three dimensionality of the channel which appears to be impossible to avoid even for extremely high aspect ratios. Using the RSM model, the results document how the channel ow contains secondary motions, sidewall boundary layers and streamwise vortices that exchange energy and momentum between the center and the side walls. Therefore, channel ows need to be calculated as a 3D problem in order to be modeled properly or to be representative of any physical laboratory experiment.
M.S. in Mechanical and Aerospace Engineering, December 2012
Show less

Title: DEVELOPMENT OF ACTIVE RESPONSE TECHNOLOGY FOR SAFETY APPLICATIONS IN POWER SAWS
Creator: Assaliyski, Marin I.
Date: 2014, 2014-05
Description: This thesis presents a study of kickback occurrences on table saws, as well as the development and evaluation of a system designed to mitigate...
Show moreThis thesis presents a study of kickback occurrences on table saws, as well as the development and evaluation of a system designed to mitigate health and property hazards due to kickbacks. A kickback is an unwanted situation during the cutting process of many powered circular saw tools, during which the operator of the tool loses control, potentially resulting in severe property and bodily harm. Multiple safety devises exist to prevent this type of situation from occurring; however, all of these devices are passive and often become a burden by decreasing e ciency, and are therefore often removed by the users. This thesis seeks to study the occurrence of kickbacks and to present an active electronic detection system that is able to aid in mitigation of potential damage to property or persons by developing responsive, robust, and practical methods of kickback detection. Implemented detection methods are presented and evaluated for performance. Concepts are also developed, presented, and discussed with the purpose of generating topics for future work. An experimental brake is used to evaluate the performance of the detection methods with an integrated system.
M.S. in Mechanical and Aerospace Engineering, May 2014
Show less

Title: ENERGY SAVINGS FOR UAV FLIGHT IN UNSTEADY GUSTING CONDITIONS THROUGH TRAJECTORY OPTIMIZATION
Creator: Grimaud, Lou
Date: 2014, 2014-07
Description: The purpose of this thesis is to show how micro unmanned aerial vehicles can extract energy from periodic wind gusts and how this energy...
Show moreThe purpose of this thesis is to show how micro unmanned aerial vehicles can extract energy from periodic wind gusts and how this energy extraction is a ected by the e ects of unsteady aerodynamics and the spatial structure of the gust component. The trajectory of a small UAV ying through wind gusts is simulated with a two degree of freedom model. The non-dimensional model is set to include vertical and horizontal gusts of varying amplitudes and durations. From this model an optimization routine is performed in order to obtain the minimum gust amplitude needed to obtain a neutral energy trajectory. With these results, it is shown that neutral energy ight is possible through gusts speeds of only 10 to 30% of the ying speed of the aircraft. Analysis of the results shows that the lift coe cient has to be changed very rapidly in order to perform these maneuvers in short duration gusts. Moreover high lift values are often required. To achieve this kind of rapid change in the lift and drag forces, fast variations of the angle of attack are needed. The high lift values also require high angles of attack that are likely to cause separation of the ow over the airfoil. These fast variations at high angle of attack are shown to cause unsteady non linear aerodynamic responses. Traditional CFD simulations are far too computationally expensive to be implemented into the optimization routine. To solve this issue a low order model based on a paper by Goman and Khrabrov [7] (GK) is developed and validated against experimental results. This model produces accurate predictions of the lift and drag coe cients for a wide range of angles of attack and for di erent type of pitch inputs. With this GK model the in uences of the unsteady aerodynamics on the energy extraction problem are highlighted. The main di erence with quasi-steady aerodynamics model was found to be for gusts at a reduced frequency (k = cf u ) higher than 0.07. Around these values the potential performance is improved by introducing the unsteady model. The trajectories obtained include more violent changes in angle of attack in order to take full advantage of the unsteady e ects.
M.S. in Mechanical, Materials, and Aerospace Engineering, July 2014
Show less

Title: DEVELOPMENT OF MULTI-NOZZLE MICRO-EXTRUDER FOR LAYERED MANUFACTURING OF MULTI-MATERIAL ENERGY STORAGE DEVICES
Creator: Mohamed Ayub, Shaik Mohamed Imran
Date: 2014, 2014-05
Description: Additive Manufacturing is critical in the development of high energy density storage devices for its flexibility to manufacture complex parts...
Show moreAdditive Manufacturing is critical in the development of high energy density storage devices for its flexibility to manufacture complex parts with different discrete compositions like cathodes, anodes and electrolytes. Such storage devices under sub- millimeter scale with micro-structured interdigitated layout could significantly improve its power and energy density. Over the past few years, scientific communities in Rapid Prototyping technology have been mainly focusing on various methods of Modeling and representing Multi-Material Object under single CAD data structure which would enable post processing and rapid prototyping of Multi-Material Object (MMO). This thesis will address the processes involved in the development of Multi-Material Micro Extrusion (M3E) device for manufacturing high density energy storage devices through discrete composition control in Solid Freeform Fabrication (SFF). The primary goal of the research is to develop a rectilinear motion platform with a multi-extrusion system and an open loop control interface to regulate the unreliable extrusion of slurries of different discrete composition. The dissertation will also address the software methodology to discretize 3D-CAD models to represent multiple material composition followed by slicing it into 2.5D layers, which will enable to create Computer Numeric Control (CNC) path program. The scope of this research is further extended to study and optimize various mechanical process inputs with respect to extrusion output parameters.
M.S. in Mechanical and Aerospace Engineering, May 2014
Show less

Title: The performance of a Harrington forced draft chain grate stoker
Creator: Barce, Stanley H, Doolittle, Charles B, Wolgemuth, Bruno E., Quinlan, Frank D.
Date: 2009, 1921
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/performanceofhar00barc
Thesis (B.S.)--Armour Institute of Technology

Title: The physical properties and tests of lubricating oils
Creator: Robechek, B., Steindler, N. A.
Date: 2009, 1917
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/physicalproperti00robe
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 33

Title: EFFECTS OF FUEL PROPERTIES ON THE COMBUSTION PROCESS OF AN ADVANCED DIESEL ENGINE
Creator: Ramos Silva, Cedric Zacarias
Date: 2015, 2015-12
Description: Internal combustion engines are encountered in our everyday lives in passenger cars and heavy-duty vehicles such as trucks and buses. While...
Show moreInternal combustion engines are encountered in our everyday lives in passenger cars and heavy-duty vehicles such as trucks and buses. While conventional compression ignition engines burn diesel fuel with an oxidizer (generally air) in a combustion chamber, much recent research has focused on improving the efficiency of combustion and reducing vehicle pollutant output through the usage of fuels with properties which differ from those of diesel fuel. In particular, this study focuses on a dual fuel engine in which two fuels (usually gasoline or diesel fuel mixed with an alternate fuel) are separately injected and combusted. Results from an Argonne National Laboratory test cell utilizing a 13 Liter (L) heavy duty dual fuel engine running in a combustion mode known as Reactivity Controlled Compression Ignition (RCCI) were leveraged in this work. In a RCCI engine, two fuels of different reactivities (low reactivity and high reactivity) are used in order to control in-cylinder fuel reactivity and allow for the optimization of combustion phasing and duration. In addition, RCCI combustion has been shown to produce low amounts of nitrogen oxides (NOx) as well as particulate matter (PM) emissions which may eliminate the need for expensive after-treatment systems. The combustion shaping capabilities and low emissions of RCCI dual fuel engines enable reductions in heat transfer losses and as such the increase of fuel efficiency. In order to understand the dynamics of such engines, a detailed simulation model of a RCCI dual fuel engine was constructed and developed using the Gamma Technologies (GT) simulation suite in particular GT-POWER and GT-SUITE. Modeling of the complex gas exchange process as well as the combustion process of the 13L RCCI dual fuel engine were both undertaken. This model was then leveraged to examine the effect of fuel properties on the combustion process using GT simulation suite. Experimental data from the 13L engine at Argonne was used to validate the models of the gas exchange and combustion processes. For the gas exchange process as well as the combustion process, the results from the simulation model fairly accurately match the experimental data from the Argonne engine. To achieve RCCI, the engine is equipped with a complex air handling system which includes two turbochargers as well as exhaust gas recirculation (EGR). To ensure that the gas exchange process was accurately captured, the experimental intake pressure, EGR fraction (EGR mass flow rate divided by the sum of EGR mass flow rate and air mass flow), fresh airflow rate, maximum in-cylinder pressure, IMEP and exhaust pressure were compared with the simulation results given by GT-POWER and GT-POST. By modeling the engine components in GT-POWER and adding additional control algorithms, the previously mentioned parameters predictions were within 10% of the engine data. The combustion process was modeled using a Direct-Injection Jet (DI-Jet) combustion model. The DI-Jet model is a predictive combustion model which predicts the burn rate, combustion rate and NOx emissions. This model was calibrated by comparing the experimental and simulation heat release curves. Particular attention is given to accurately capturing the start of combustion and ignition delay period because they affect the combustion process the most.
M.S. in Mechanical and Aerospace Engineering, December 2015
Show less

Title: Design, installation and operation of cams for the valve-gear of a three-cylinder, 8 x 10 in. Westinghouse gas engine
Creator: Paterson, William, Bunge, Ludwig W. A
Date: 2009, 1915
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/designinstallati00pate
Thesis (B.S.)--Armour Institute of Technology, 1915 B.S. in Mechanical Engineering, 1915

Title: Design and installation of power plant and heating system for the zone of camp activities and amusements, Camp Funston, Kansas
Creator: Pimstein, Sidney.
Date: 2009, 1919
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/designinstallati00pims
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket

Title: Design of an exhaust gas calorimeter for automobile engines
Creator: Mayer, J. Leo., Hibbard, Lewis E
Date: 2009, 1915
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/designofexhaustg00maye
Thesis (B.S.)--Armour Institute of Technology, 1915 B.S. in Mechanical Engineering, 1915

Title: The design of a tractor for general farm and road work
Creator: Evans, R. T.
Date: 2009, 1917
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/designoftractorf00evan
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket

Title: Economy tests of 40 H. P. automobile engine including construction and operation of manograph
Creator: Lawrence, M. F, Dunn, W. C.
Date: 2009, 1912
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/economytestsof4000lawr
Thesis (B.S.)--Armour Institute of Technology, 1912 B.S. in Mechanical Engineering, 1912

Title: Economical banking of fires with a green chain grate storker
Creator: Hayes, J. J., Jr, Jarvis, B. H.
Date: 2009, 1913
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/economicalbankin00haye
Thesis (B.S.)--Armour Institute of Technology

Title: Economy and capacity test of a three ton York ice plant
Creator: Sir, Walter Waldemar., Bohn, Robert, Cooley, Gilbert
Date: 2009, 1914
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/economycapacityt00sirw
Thesis (B.S.)--Armour Institute of Technology, 1914 Includes bibliographical references ...
Show morehttp://www.archive.org/details/economycapacityt00sirw
Thesis (B.S.)--Armour Institute of Technology, 1914 Includes bibliographical references (leaf 26) and index B.S. in Mechanical Engineering, 1914
Show less

Title: An economy analysis of automobile engines by a new method
Creator: White, H. S., Fritze, G. M., King, L. A.
Date: 2009, 1917
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/economyanalysiso00whit
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket

Title: Efficiency test of a hydro-electric plant
Date: 2009, 1910
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/effeciencytestof00baug
Thesis (B.S.)--Armour Institute of Technology, 1910 B.S. in Mechanical Engineering, 1910

Title: The effect in economy of an automobile engine of varying the igniter and fuel valve opening
Creator: Dekker, Harry G., Mayes, Frank H.
Date: 2009, 1909
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/effectineconomyo00dekk
Thesis (B.S.)--Armour Institute of Technology; Includes bibliographical references and index

repository.iit

Search the repository

Pages

Pages

Enabled Filters

Refine Results

Type

Date

Academic status of creator

Subject

Creator