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- Creators: Debussy, Claude, 1862-1918
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) 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
ContributorsDebussy, Claude, 1862-1918 (Composer)
ContributorsDebussy, Claude, 1862-1918 (Composer)
ContributorsDebussy, Claude, 1862-1918 (Composer)
ContributorsDebussy, Claude, 1862-1918 (Composer)
ContributorsDebussy, Claude, 1862-1918 (Composer)
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 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.
(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
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 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
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 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.
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
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 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