Matching Items (68)

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Convection Heat Transfer in Mineral Oil CPU Immersion Cooling

Description

In this paper, the effectiveness and practical applications of cooling a computer's CPU using mineral oil is investigated. A computer processor or CPU may be immersed along with other electronics

In this paper, the effectiveness and practical applications of cooling a computer's CPU using mineral oil is investigated. A computer processor or CPU may be immersed along with other electronics in mineral oil and still be operational. The mineral oil acts as a dielectric and prevents shorts in the electronics while also being thermally conductive and cooling the CPU. A simple comparison of a flat plate immersed in air versus mineral oil is considered using analytical natural convection correlations. The result of this comparison indicates that the plate cooled by natural convection in air would operate at 98.41[°C] while the plate cooled by mineral oil would operate at 32.20 [°C]. Next, CFD in ANSYS Fluent was used to conduct simulation with forced convection representing a CPU fan driving fluid flow to cool the CPU. A comparison is made between cooling done with air and mineral oil. The results of the CFD simulation results indicate that using mineral oil as a substitute to air as the cooling fluid reduced the CPU operating temperature by sixty degrees Celsius. The use of mineral oil as a cooling fluid for a consumer computer has valid thermal benefits, but the practical challenges of the method will likely prevent widespread adoption.

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Date Created
  • 2016-12

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CFD Analysis of a Wind Turbine Airfoil with Active Flow Control

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

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.

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Created

Date Created
  • 2018-05

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Modeling Trajectories of Supersonic Projectiles

Description

The goal of this thesis project was to build an understanding of supersonic projectile dynamics through the creation of a trajectory model that incorporates several different aerodynamic concepts and builds

The goal of this thesis project was to build an understanding of supersonic projectile dynamics through the creation of a trajectory model that incorporates several different aerodynamic concepts and builds a criteria for the stability of a projectile. This was done iteratively where the model was built from a foundation of kinematics with various aerodynamic principles being added incrementally. The primary aerodynamic principle that influenced the trajectory of the projectile was in the coefficient of drag. The drag coefficient was split into three primary components: the form drag, skin friction drag, and base pressure drag. These together made up the core of the model, additional complexity served to increase the accuracy of the model and generalize to different projectile profiles.

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Created

Date Created
  • 2020-05

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Effects of Diffusers with and without Vortex Generators on Overall Flow and Velocity Distribution

Description

An in-depth analysis on the effects vortex generators cause to the boundary layer separation that occurs when an internal flow passes through a diffuser is presented. By understanding the effects

An in-depth analysis on the effects vortex generators cause to the boundary layer separation that occurs when an internal flow passes through a diffuser is presented. By understanding the effects vortex generators demonstrate on the boundary layer, they can be utilized to improve the performance and efficiencies of diffusers and other internal flow applications. An experiment was constructed to acquire physical data that could assess the change in performance of the diffusers once vortex generators were applied. The experiment consisted of pushing air through rectangular diffusers with half angles of 10, 20, and 30 degrees. A velocity distribution model was created for each diffuser without the application of vortex generators before modeling the velocity distribution with the application of vortex generators. This allowed the two results to be directly compared to one another and the improvements to be quantified. This was completed by using the velocity distribution model to find the partial mass flow rate through the outer portion of the diffuser's cross-sectional area. The analysis concluded that the vortex generators noticeably increased the performance of the diffusers. This was best seen in the performance of the 30-degree diffuser. Initially the diffuser experienced airflow velocities near zero towards the edges. This led to 0.18% of the mass flow rate occurring in the outer one-fourth portion of the cross-sectional area. With the application of vortex generators, this percentage increased to 5.7%. The 20-degree diffuser improved from 2.5% to 7.9% of the total mass flow rate in the outer portion and the 10-degree diffuser improved from 11.9% to 19.2%. These results demonstrate an increase in performance by the addition of vortex generators while allowing the possibility for further investigation on improvement through the design and configuration of these vortex generators.

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Created

Date Created
  • 2018-05

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Aerodynamic Stability of Small Bluff Bodied Vehicle

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

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.

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Created

Date Created
  • 2018-05

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Edible Microfluidics: 3D Printing Hydrogels Using a Co-Flow Nozzle Extruder

Description

3D printing has recently become a popular manufacturing process and the goal of the project was to take that process to the kitchen. This was done by utilizing existing knowledge

3D printing has recently become a popular manufacturing process and the goal of the project was to take that process to the kitchen. This was done by utilizing existing knowledge of the culinary process of "spherification", by which a liquid is encapsulated in an edible shell, and combining it with the hydrogel research advancements in tissue engineering to make robust fibers. A co-flow nozzle was constructed and the two fluids needed for spherification were flowed in various configurations to create different fibers. By outlining a stability regime and measuring the outer diameters for both regular and reverse spherification, the optimal method of production and fibers that would be suitable for 3D printing were discovered. The results of the experiments can be used to begin 3D printing edible 2D patterns and eventually 3D structures.

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Created

Date Created
  • 2015-05

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Experimental Validation of a Computational Fluid Dynamics Spray Pattern Simulation for a Bi-propellant Liquid Rocket Engine Injector Plate Assembly

Description

The liquid rocket engine, more specifically, the bi-propellant liquid rocket engine, is a popular type of chemical propulsion system within the propulsion industry due to its relatively high specific impulse

The liquid rocket engine, more specifically, the bi-propellant liquid rocket engine, is a popular type of chemical propulsion system within the propulsion industry due to its relatively high specific impulse and high thrust levels compared to the other chemical propulsion choices. For the purposes of this thesis, a bi-propellant liquid rocket engine system consists of a rocket engine, a set of tanks for the storage and supply of liquid propellants, and everything required in between for thrust-producing operation. Among the hardware in this "in between" necessary for a liquid rocket engine to produce thrust exists an injector, or an assembly of injector elements, whose purpose is to introduce and meter the flow of the fuel and oxidizer of the liquid rocket engine into the combustion chamber. To do this the injector or injector assembly, upon injection into the combustion chamber, must cause the two liquids to break up into small droplets, proportionally and uniformly distribute and mix the liquid into a spray pattern within the combustion chamber, and allow for engine combustion to occur as efficiently as possible. Daedalus Astronautics @ ASU, one of Arizona State University's engineering student organizations, has been working to design, construct, and successfully test a bi-propellant liquid rocket engine of its own. In doing so, Daedalus Astronautics has designed a bi-propellant liquid rocket engine injector assembly consisting of a forward bulkhead and an injector plate. The purpose of this thesis is to experimentally verify the flow of liquid through this injector assembly modeled using computational fluid dynamics methods. During the two semester time line allowed for this thesis project, a mesh was created for a single orifice geometry injector plate and combustion chamber assembly in ANSYS ICEM CFD and an experiment was designed for imaging the spray pattern from the injector plate and forward bulkhead assembly, from which several things about the injector geometry design were discovered.

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Created

Date Created
  • 2015-05

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Validating a New CFD Algorithm by Finding the Drag Coefficient of a Sphere

Description

A novel CFD algorithm called LEAP is currently being developed by the Kasbaoui Research Group (KRG) using the Immersed Boundary Method (IBM) to describe complex geometries. To validate the algorithm,

A novel CFD algorithm called LEAP is currently being developed by the Kasbaoui Research Group (KRG) using the Immersed Boundary Method (IBM) to describe complex geometries. To validate the algorithm, this research project focused on testing the algorithm in three dimensions by simulating a sphere placed in a moving fluid. The simulation results were compared against the experimentally derived Schiller-Naumann Correlation. Over the course of 36 trials, various spatial and temporal resolutions were tested at specific Reynolds numbers between 10 and 300. It was observed that numerical errors decreased with increasing spatial and temporal resolution. This result was expected as increased resolution should give results closer to experimental values. Having shown the accuracy and robustness of this method, KRG will continue to develop this algorithm to explore more complex geometries such as aircraft engines or human lungs.

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Created

Date Created
  • 2021-05

Design and Analyze a Liquid-Liquid Swirl Coaxial Injector for a small-scale rocket engine using Computational Fluid Dynamics for minimum pressure drop and maximum spray angle.

Description

Atomization of fluids inside combustion chamber has been a very complex and long-lasting subject that is still researched into for maximum efficiency in mixing oxidizer and fuel. This thesis focuses

Atomization of fluids inside combustion chamber has been a very complex and long-lasting subject that is still researched into for maximum efficiency in mixing oxidizer and fuel. This thesis focuses on an injector called the Liquid-Liquid Swirl Coaxial Injector (LLSC) to be used in a small-scale rocket engine due to its high efficiency in spray angles and low pressure drops. Injectors are the elements that exist as a connection in between the plumbing and the combustion chamber of the rocket engine. The performance of injectors can greatly affect the stability and efficiency of the engine. Injectors proportionally help breakup the fluid into small droplets that help in the efficiency of vaporization of fluids while combusting. Helios Rocketry, Arizona State University’s student-led engineering organization, is working to design and successfully launch a small-scale bi-propellant liquid rocket engine to a 100 km (Karman Line) in space as part of the Base11 challenge. For this task a highly efficient injector element needed to be designed that can achieve high amounts of atomization with a large spray angle, to help with combustion in a relatively small sized chamber. The purpose of this thesis is to explore a specific type of injector element called a LLSC injector element. This is performed by simulating it through an LES model in computational fluid dynamics using a Voronoi based meshing scheme, by using codes from Cascade Technologies. In the end a 35-injector element design was used for an injector plate. This helped minimize the pressure drop and keep the wall stress below the safety limit.

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Created

Date Created
  • 2019-05

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The Analysis of the Airflow around a Rotating Cylindrical Arrow

Description

This honors thesis explores and models the flow of air around a cylindrical arrow that is rotating as it moves through the air. This model represents the airflow around an

This honors thesis explores and models the flow of air around a cylindrical arrow that is rotating as it moves through the air. This model represents the airflow around an archery arrow after it is released from the bow and rotates while it flies through the air. This situation is important in archery because an understanding of the airflow allows archers to predict the flight of the arrow. As a result, archers can improve their accuracy and ability to hit targets. However, not many computational fluid dynamic simulations modeling the airflow around a rotating archery arrow exist. This thesis attempts to further the understanding of the airflow around a rotating archery arrow by creating a mathematical model to numerically simulate the airflow around the arrow in the presence of this rotation. This thesis uses a linearized approximation of the Navier Stokes equations to model the airflow around the arrow and explains the reasoning for using this simplification of the fully nonlinear Navier Stokes equations. This thesis continues to describe the discretization of these linearized equations using the finite difference method and the boundary conditions used for these equations. A MATLAB code solves the resulting system of equations in order to obtain a numerical simulation of this airflow around the rotating arrow. The results of the simulation for each velocity component and the pressure distribution are displayed. This thesis then discusses the results of the simulation, and the MATLAB code is analyzed to verify the convergence of the solution. Appendix A includes the full MATLAB code used for the flow simulation. Finally, this thesis explains potential future research topics, ideas, and improvements to the code that can help further the understanding and create more realistic simulations of the airflow around a flying archery arrow.

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Created

Date Created
  • 2019-05