Matching Items (35)
Description
This thesis seeks to further explore off-design point operation of gas turbines and to examine the capabilities of GasTurb 12 as a tool for off-design analysis. It is a continuation of previous thesis work which initially explored the capabilities of GasTurb 12. The research is conducted in order to: 1)

This thesis seeks to further explore off-design point operation of gas turbines and to examine the capabilities of GasTurb 12 as a tool for off-design analysis. It is a continuation of previous thesis work which initially explored the capabilities of GasTurb 12. The research is conducted in order to: 1) validate GasTurb 12 and, 2) predict off-design performance of the Garrett GTCP85-98D located at the Arizona State University Tempe campus. GasTurb 12 is validated as an off-design point tool by using the program to predict performance of an LM2500+ marine gas turbine. Haglind and Elmegaard (2009) published a paper detailing a second off-design point method and it includes the manufacturer's off-design point data for the LM2500+. GasTurb 12 is used to predict off-design point performance of the LM2500+ and compared to the manufacturer's data. The GasTurb 12 predictions show good correlation. Garrett has published specification data for the GTCP85-98D. This specification data is analyzed to determine the design point and to comment on off-design trends. Arizona State University GTCP85-98D off-design experimental data is evaluated. Trends presented in the data are commented on and explained. The trends match the expected behavior demonstrated in the specification data for the same gas turbine system. It was originally intended that a model of the GTCP85-98D be constructed in GasTurb 12 and used to predict off-design performance. The prediction would be compared to collected experimental data. This is not possible because the free version of GasTurb 12 used in this research does not have a module to model a single spool turboshaft. This module needs to be purchased for this analysis.
ContributorsMartinjako, Jeremy (Author) / Trimble, Steve (Thesis advisor) / Dahm, Werner (Committee member) / Middleton, James (Committee member) / Arizona State University (Publisher)
Created2014
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Description
This thesis uses an aircraft aerodynamic model and propulsion data, which

represents a configuration similar to the Airbus A320, to perform trade studies to understand the weight and configuration effects of “out-of-trim” flight during takeoff, cruise, initial approach, and balked landing. It is found that flying an aircraft slightly above the

This thesis uses an aircraft aerodynamic model and propulsion data, which

represents a configuration similar to the Airbus A320, to perform trade studies to understand the weight and configuration effects of “out-of-trim” flight during takeoff, cruise, initial approach, and balked landing. It is found that flying an aircraft slightly above the angle of attack or pitch angle required for a trimmed, stabilized flight will cause the aircraft to lose speed rapidly. This effect is most noticeable for lighter aircraft and when one engine is rendered inoperative. In the event of an engine failure, if the pilot does not pitch the nose of the aircraft down quickly, speed losses are significant and potentially lead to stalling the aircraft. Even when the risk of stalling the aircraft is small, the implications on aircraft climb performance, obstacle clearance, and acceleration distances can still become problematic if the aircraft is not flown properly. When the aircraft is slightly above the trimmed angle of attack, the response is shown to closely follow the classical phugoid response where the aircraft will trade speed and altitude in an oscillatory manner. However, when the pitch angle is slightly above the trimmed condition, the aircraft does not show this phugoid pattern but instead just loses speed until it reaches a new stabilized trajectory, never having speed and altitude oscillate. In this event, the way a pilot should respond to both events is different and may cause confusion in the cockpit.
ContributorsDelisle, Mathew Robert (Author) / Takahashi, Timothy (Thesis advisor) / White, Daniel (Committee member) / Niemczyk, Mary (Committee member) / Arizona State University (Publisher)
Created2018
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Description
Two methods of improving the life and efficiency of the Pulsed Inductive Thruster

(PIT) have been investigated. The first is a trade study of available switches to

determine the best device to implement in the PIT design. The second is the design

of a coil to improve coupling between the accelerator coil and

Two methods of improving the life and efficiency of the Pulsed Inductive Thruster

(PIT) have been investigated. The first is a trade study of available switches to

determine the best device to implement in the PIT design. The second is the design

of a coil to improve coupling between the accelerator coil and the plasma. Experiments

were done with both permanent and electromagnets to investigate the feasibility of

implementing a modified Halbach array within the PIT to promote better plasma

coupling and decrease the unused space within the thruster. This array proved to

promote more complete coupling on the edges of the coil where it had been weak in

previous studies. Numerical analysis was done to predict the performance of a PIT

that utilized each suggested switch type. This model utilized the Alfven velocity to

determine the critical mass and energy of these theoretical thrusters.
ContributorsRaines, Taylor (Author) / Takahashi, Timothy T (Thesis advisor) / White, Daniel B (Committee member) / Dahm, Werner (Committee member) / Arizona State University (Publisher)
Created2018
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Description
In previous work, the effects of power extraction for onboard electrical equipment and flight control systems were studied to determine which turbine shaft (i.e. high power shaft vs low power shaft) is best suited for power extraction. This thesis will look into an alternative option, a three-spool design with a

In previous work, the effects of power extraction for onboard electrical equipment and flight control systems were studied to determine which turbine shaft (i.e. high power shaft vs low power shaft) is best suited for power extraction. This thesis will look into an alternative option, a three-spool design with a high-pressure turbine, low-pressure turbine, and a turbine dedicated to driving the fan. One of the three-spool turbines is designed to be a vaneless counter-rotating turbine. The off-design performance of this new design will be compared to the traditional two-spool design to determine if the additional spool is a practical alternative to current designs for high shaft horsepower extraction requirements. Upon analysis, this thesis has shown that a three-spool engine with a vaneless counter-rotating stage has worse performance characteristics than traditional two-spool designs for UAV systems.
ContributorsBurgett, Luke Michael (Author) / Takahashi, Timothy (Thesis advisor) / Dahm, Werner (Committee member) / Trimble, Steve (Committee member) / Arizona State University (Publisher)
Created2019
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Description
Laser radars or lidar’s have been used extensively to remotely study winds within the atmospheric boundary layer and atmospheric transport. Lidar sensors have become an important tool within the meteorology and the wind energy community. For example, Doppler lidars are used frequently in wind resource assessment, wind turbine control as

Laser radars or lidar’s have been used extensively to remotely study winds within the atmospheric boundary layer and atmospheric transport. Lidar sensors have become an important tool within the meteorology and the wind energy community. For example, Doppler lidars are used frequently in wind resource assessment, wind turbine control as well as in atmospheric science research. A Time of Flight based (ToF) direct detection lidar sensor is used in vehicles to navigate through complex and dynamic environments autonomously. These optical sensors are used to map the environment around the car accurately for perception and localization tasks that help achieve complete autonomy.

This thesis begins with a detailed discussion on the fundamentals of a Doppler lidar system. The laser signal flow path to and from the target, the optics of the system and the core signal processing algorithms used to extract velocity information, were studied to get closer to the hardware of a Doppler lidar sensor. A Doppler lidar simulator was built to study the existing signal processing algorithms to detect and estimate doppler frequency, and radial velocity information. Understanding the sensor and its processing at the hardware level is necessary to develop new algorithms to detect and track specific flow structures in the atmosphere. For example, the aircraft vortices have been a topic of extensive research and doppler lidars have proved to be a valuable sensor to detect and track these coherent flow structures. Using the lidar simulator a physics based doppler lidar vortex algorithm is tested on simulated data to track a pair of counter rotating aircraft vortices.



At a system level the major components of a time of flight lidar is very similar to a Doppler lidar. The fundamental physics of operation is however different. While doppler lidars are used for radial velocity measurement, ToF sensors as the name suggests provides precise depth measurements by measuring time of flight between the transmitted and the received pulses. The second part of this dissertation begins to explore the details of ToF lidar system. A system level design, to build a ToF direct detection lidar system is presented. Different lidar sensor modalities that are currently used with sensors in the market today for automotive applications were evaluated and a 2D MEMS based scanning lidar system was designed using off-the shelf components.

Finally, a range of experiments and tests were completed to evaluate the performance of each sub-component of the lidar sensor prototype. A major portion of the testing was done to align the optics of the system and to ensure maximum field of view overlap for the bi-static laser sensor. As a laser range finder, the system demonstrated capabilities to detect hard targets as far as 32 meters. Time to digital converter (TDC) and an analog to digital converter (ADC) was used for providing accurate timing solutions for the lidar prototype. A Matlab lidar model was built and used to perform trade-off studies that helped choosing components to suit the sensor design specifications.

The size, weight and cost of these lidar sensors are still very high and thus making it harder for automotive manufacturers to integrate these sensors into their vehicles. Ongoing research in this field is determined to find a solution that guarantees very high performance in real time and lower its cost over the next decade as components get cheaper and can be seamlessly integrated with cars to improve on-road safety.
ContributorsBhaskaran, Sreevatsan (Author) / Calhoun, Ronald J (Thesis advisor) / Dahm, Werner (Committee member) / Huang, Huei-Ping (Committee member) / Chen, Kang Pin (Committee member) / Choukulkar, Aditya (Committee member) / Arizona State University (Publisher)
Created2018
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Description
The objective of this project was to design an electrically driven centrifugal pump for the Daedalus Astronautics @ASU hybrid rocket engine (HRE). The pump design was purposefully simplified due to time, fabrication, calculation, and capability constraints, which resulted in a lower fidelity design, with the option to be improved later.

The objective of this project was to design an electrically driven centrifugal pump for the Daedalus Astronautics @ASU hybrid rocket engine (HRE). The pump design was purposefully simplified due to time, fabrication, calculation, and capability constraints, which resulted in a lower fidelity design, with the option to be improved later. The impeller, shroud, volute, shaft, motor, and ESC were the main focuses of the pump assembly, but the seals, bearings, lubrication methods, and flow path connections were considered as elements which would require future attention. The resulting pump design is intended to be used on the Daedalus Astronautics HRE test cart for design verification. In the future, trade studies and more detailed analyses should and will be performed before this pump is integrated into the Daedalus Astronautics flight-ready HRE.
ContributorsShillingburg, Ryan Carl (Author) / White, Daniel (Thesis director) / Brunacini, Lauren (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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Description
This experiment used hotwire anemometry to examine the von Kármán vortex street and how different surface conditions affect the wake profile of circular airfoils, or bluff bodies. Specifically, this experiment investigated how the various surface conditions affected the shedding frequency and Strouhal Number of the vortex street as Reynolds Number

This experiment used hotwire anemometry to examine the von Kármán vortex street and how different surface conditions affect the wake profile of circular airfoils, or bluff bodies. Specifically, this experiment investigated how the various surface conditions affected the shedding frequency and Strouhal Number of the vortex street as Reynolds Number is increased. The cylinders tested varied diameter, surface finish, and wire wrapping. Larger diameters corresponded with lower shedding frequencies, rougher surfaces decreased Strouhal Number, and the addition of thick wires to the surface of the cylinder completely disrupted the vortex shedding to the point where there was almost no dominant shedding frequency. For the smallest diameter cylinder tested, secondary dominant frequencies were observed, suggesting harmonics.
ContributorsCoote, Peter John (Author) / Takahashi, Timothy (Thesis director) / White, Daniel (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
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Description
The Phoenix CubeSat is a 3U Earth imaging CubeSat which will take infrared (IR) photos of cities in the United Stated to study the Urban Heat Island Effect, (UHI) from low earth orbit (LEO). It has many different components that need to be powered during the life of its mission.

The Phoenix CubeSat is a 3U Earth imaging CubeSat which will take infrared (IR) photos of cities in the United Stated to study the Urban Heat Island Effect, (UHI) from low earth orbit (LEO). It has many different components that need to be powered during the life of its mission. The only power source during the mission will be its solar panels. It is difficult to calculate power generation from solar panels by hand because of the different orientations the satellite will be positioned in during orbit; therefore, simulation will be used to produce power generation data. Knowing how much power is generated is integral to balancing the power budget, confirming whether there is enough power for all the components, and knowing whether there will be enough power in the batteries during eclipse. This data will be used to create an optimal design for the Phoenix CubeSat to accomplish its mission.
ContributorsBarakat, Raymond John (Author) / White, Daniel (Thesis director) / Kitchen, Jennifer (Committee member) / Electrical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
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Description
The purpose of my Honors Thesis was to generate a tool that could be implemented by Aerospace students at Arizona State University. This tool was created using MatLab which is the current program students are using. The modeling system that was generated goes step-by-step through the flow of a two

The purpose of my Honors Thesis was to generate a tool that could be implemented by Aerospace students at Arizona State University. This tool was created using MatLab which is the current program students are using. The modeling system that was generated goes step-by-step through the flow of a two spool gas turbine engine. The code was then compared to an ideal case engine with predictable values. It was found to have less than a 3 percent error for these parameters, which included optimal net work produced, optimal overall pressure ratio, and maximum pressure ratio. The modeling system was then run through a parametric analysis. In the first case, the bypass ratio was set to 0 and the freestream Mach number was set to 0. The second case was with a bypass ratio of 0 and fresstream Mach number of 0.85. The third case was with a bypass ratio of 5 and freestream Mach number of 0. The fourth case was with a bypass ratio of 5 and fresstream Mach number of 0.85. Each of these cases was run at various overall pressure ratios and maximum Temperatures of 1500 K, 1600 K and 1700 K. The results modeled the behavior that was expected. As the freestream Mach number was increased, the thrust decreased and the thrust specific fuel consumption increased, corresponding to an increase in total pressure at the combustor inlet. It was also found that the thrust was increased and the thrust specific fuel consumption decreased as the bypass ratio was increased. These results also make sense as there is less airflow passing through the engine core. Finally the engine was compared to two real engines. Both of which are General Electric G6 series engines. For the 80C2A3 engine, the percent difference between thrust and thrust specific fuel consumption was less than five percent. For the 50B, the thrust was below a two percent difference, but the thrust specific fuel consumption clearly provided inaccurate results. This could be caused by the lack of inputs provided by General Electric. The amount of fuel injected is largely dependent on the maximum temperature which is not available to the public. Overall, the code produces comparable results to real engines and can display how isolating and modifying a certain parameter effects engine performance.
ContributorsCook, Rachel Nicole (Author) / Dahm, Werner (Thesis director) / Lee, Taewoo (Committee member) / Wells, Valana (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2015-05
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Description
Active pixel sensors hold a lot of promise for space applications in star tracking because of their effectiveness against radiation, small size, and on-chip processing. The research focus is on documenting and validating ground test equipment for these types of sensors. Through demonstrating the utility of a commercial sensor, the

Active pixel sensors hold a lot of promise for space applications in star tracking because of their effectiveness against radiation, small size, and on-chip processing. The research focus is on documenting and validating ground test equipment for these types of sensors. Through demonstrating the utility of a commercial sensor, the research will be able to work on ensuring the accuracy of ground tests. This contribution allows for future research on improving active pixel sensor performance.
ContributorsDotson, Breydan Lane (Author) / White, Daniel (Thesis director) / Jansen, Rolf (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05