Matching Items (30)
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- All Subjects: Aerospace
- All Subjects: Aerodynamics
- Creators: Mechanical and Aerospace Engineering Program
- Creators: Adams, James
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 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
Description
Honeywell is currently extending the reach of additive manufacturing (AM) in its product line and expects to produce as much as 40% of its inventory through AM in five years. Additive manufacturing itself is expected to grow into a $3.1 billion dollar industry in the next 5 to 10 years. Reusing IN 718 powder, a nickel-based super alloy metal powder, is an ideal option to reduce costs as well as reduce waste because it can be used with additive manufacturing, but the main obstacles are lack of procedure standardization and product quality assurances from this process. The goal of the capstone project, "Effect of Powder Reuse on DMLS (Direct Metal Laser Sintering) Product Integrity," is to create a powder characterization protocol in order to determine if the IN 718 powder can be reused and what effect the IN 718 reused powder has on the mechanical properties of the products Honeywell fabricates. To provide context and impact of this capstone project, this paper serves to identify the benefits of AM for Honeywell and the cost effectiveness of reusing the powder versus using virgin powder every time. It was found that Honeywell's investment in AM is due to the cost effectiveness of AM, versatility in product design, and to ensure Honeywell remains competitive in the future. In terms of reducing expenses, reusing powder enables costs to be approximately 45% less than using virgin powder. With these key pieces of information, the motivations for this capstone project are understood to a fuller and more profound degree.
ContributorsQuigley, Elizabeth (Co-author) / Luo, Zheyu (Co-author) / Murella, Anoosha (Co-author) / Lee, Wey Lyn (Co-author) / Adams, James (Thesis director) / Tasooji, Amaneh (Committee member) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Active flow control for airfoil designs has been researched for the past few decades. This has been achieved through steady blowing, pulsed blowing, synthetic jets, and plasma jets. These techniques have been applied to both single and dual jet configurations. This technology was examined for a wind turbine blade application so that lift and drag can be altered without needing a mechanical flap. Research was completed to also allow for thicker airfoils with more blunt trailing edges that result in the higher structural strength needed for large, heavy wind turbine blades without the negative aerodynamic effects such as boundary layer separation. This research tested steady blowing in a dual jet configuration for the S830 airfoil from the National Renewable Energy Laboratory (NREL) database of airfoils. Computational Fluid Dynamics was used in the software Ansys Fluent. Calculations were completed for a modified S830 airfoil with a rounded trailing edge surface at momentum coefficients of 0.01 for the lower jet and 0.1, 0.12, and 0.14 for the upper jet. These results were then compared to the original S830 results for the lift over drag efficiency. The design with momentum coefficients of 0.12 for the upper surface resulted in the highest increase in efficiency of 53% at an angle of attack of 12 degrees. At this momentum coefficient, the angle of attack where zero lift occurred was at -8.62 degrees, compared to the case with no blowing at -1.90 degrees. From previous research and research completed in this thesis it was concluded that active flow control is an effective technique to improve wind turbine energy collection.
ContributorsStapleton, Paige (Author) / Mertz, Benjamin (Thesis director) / Herrmann, Marcus (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
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 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
Description
The purpose of this project is to determine the feasibility of a water tunnel designed to meet certain constraints. The project goals are to tailor a design for a given location, and to produce a repeatable design sizing and shape process for specified constraints. The primary design goals include a 1 m/s flow velocity in a 30cm x 30cm test section for 300 seconds. Secondary parameters, such as system height, tank height, area contraction ratio, and roof loading limits, may change depending on preference, location, or environment. The final chosen configuration is a gravity fed design with six major components: the reservoir tank, the initial duct, the contraction nozzle, the test section, the exit duct, and the variable control exit nozzle. Important sizing results include a minimum water weight of 60,000 pounds, a system height of 7.65 meters, a system length of 6 meters (not including the reservoir tank), a large shallow reservoir tank width of 12.2 meters, and height of 0.22 meters, and a control nozzle exit radius range of 5.25 cm to 5.3 cm. Computational fluid dynamic simulation further supports adherence to the design constraints but points out some potential areas for improvement in dealing with flow irregularities. These areas include the bends in the ducts, and the contraction nozzle. Despite those areas recommended for improvement, it is reasonable to conclude that the design and process fulfill the project goals.
ContributorsZykan, Brandt Davis Healy (Author) / Wells, Valana (Thesis director) / Middleton, James (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2014-05
Description
The emerging market for unmanned aerial vehicles, or UAV's, demands the development of effective design tools for small-scale aircraft. This research seeks to validate a previously developed drag build-up method for small air vehicles. Using the method, a drag prediction was made for an off-the-shelf, remotely controlled aircraft. The Oswald efficiency was predicted to be 0.852. Flight tests were then conducted using the RC plane, and the aircraft performance data was compared with the predicted performance data. Although there were variations in the data due to flight conditions and equipment, the drag build up method was capable of predicting the aircraft's drag. The experimental Oswald efficiency was found to be 0.863 with an error of 1.27%. As for the CDp the prediction of 0.0477 was comparable to the experimental value of 0.0424. Moving forward this method can be used to create conceptual designs of UAV's to explore the most efficient designs, without the need to build a model.
ContributorsGavin, Tyler Joseph (Author) / Wells, Valana (Thesis director) / Garrett, Fred (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2014-05
Description
This work describes the numerical process developed for use of rocket engine nozzle ejectors. Ejector nozzles, while applied to jet engines extensively, have not been applied to rockets, and have great potential to improve the performance of endoatmospheric rocket propulsion systems. Utilizing the low pressure, high velocity flow in the plume, this secondary structure entrains a secondary mass flow to increase the mass flow of the propulsion system. Rocket engine nozzle ejectors must be designed with the high supersonic conditions associated with rocket engines. These designs rely on the numerical process described in this paper.
ContributorsGibson, Gaines Sullivan (Author) / Wells, Valana (Thesis director) / Takahashi, Timothy (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2014-05
Description
The aerospace industry has been conducting research on the additive manufacturing (AM) process since the 1980's, but companies have recently just begun to apply AM in hopes that this new technology will meet or exceed the requirements met by previous manufacturing methods, as well as producing more cost effective, geometrically-complex products. This investigation evaluated the performance of 3D-printed aerospace test specimens made by Powder Bed Fusion Technologies, and compared them to forged specimens. A design of experiments varying build parameters was conducted in order to determine AM component porosity. Factors such as powder post-processing, directionality of the build, and fractology of the samples were evaluated through tensile strength testing and hardness testing of Inconel 718 wrought and EBM printed materials. Using electron microsopy, the responses to these factors were analyzed for stress fractures, grain boundaries, and other defects that occurred in the testing process. The comparison determined which metallurgical process provides the most effective material for aircraft usage.
ContributorsNez, Brittany Amber (Author) / Parsey, John (Thesis director) / Hsu, Keng (Committee member) / Godfrey, Donald (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
This paper studies the history and development of ion propulsion systems and survey past, present, and developing technology with their applications to space missions. This analysis addresses the physical design parameters and process that is a part of designing and optimizing a gridded ion thruster. It also identifies operational limits that may be associated with solar-powered ion propulsion systems and posits plausible solutions or alternatives to remedy such limitations. These topics are presented with the intent of reviewing how ion propulsion technology evolved in its journey to develop to today's systems, and to facilitate thought and discussion on where further development of ion propulsion systems can be directed.
ContributorsTang, Justine (Author) / White, Daniel (Thesis director) / Dahm, Werner (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Each year, the CanSat Competition organizers release aerospace based engineering mission objectives for collegiate teams to compete in. This year, the design is an aerodynamically stable probe that will descend from an altitude of 725 meters at a rate between 10-30 meters/sec until it reaches an altitude of 300 meters, where it will then release a parachute as its aerobraking mechanism as it descends at 5 meters/sec until it reaches the ground. The focus of this paper is to investigate the design of the probe itself and how slender body theory and cross flow drag affect the lift and aerodynamic stability of this bluff body. A tool is developed inside of MATLAB which calculates the slender body lift as well as the lift from the cross flow drag. It then uses that information to calculate the total moment about the center of gravity for a range of angles of attack and free stream velocities. This tool is then used to optimize the geometry of the probe. These geometries are used to construct a prototype and that prototype is tested by a drop test from a 6-story building. The initial tests confirm the calculations that the probe, bluff body, is stable and self-correcting in its descent. Future work involves more high-altitude and ground-level tests that will further verify and improve on the current design.
ContributorsMcCourt, Anthony Michael (Author) / Takahashi, Timothy (Thesis director) / Herrmann, Marcus (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05