Master of Science, The Ohio State University, 2023, Mechanical Engineering

In this research study, fuel sloshing for automotive applications isexperimentally observed inside a rectangular acrylic tank. A customized experimental setup includes a fuel tank that is designed (using CAD software) and manufactured using various machining techniques for each of the individual components. The experiment uses a high speed hydraulic actuator (2200 lbf capacity) to slosh a tank of volume 17.5 gallons up to a maximum speed of 2 mph. A triangular mechanical linkage is used to connect the actuator to the fuel tank and provide displacement and velocity amplification factor of 3:1. Experimental components and fixtures are designed such that various test conditions can be observed. This includes the tank inclination angle, and number and positions of baffles within the tank. In addition the percentage fill of the tank, and tank velocity are several parameters that are varied to investigate the change in fuel slosh. The pressure exerted by the fluid on the walls of the tank is measured by with the help of pressure transducers (0-5psig) at 10 distinct locations on the tank. The variation of pressure with time is observed by connecting pressure transducers to a National Instruments PXI Express data acquisition device and visualized using LabVIEW. Furthermore, the free surface of the fluid (water) is recorded using the Photron SA1 high-speed camera. The fluid (dyed dark blue to increase contrast) is tracked from raw high speed camera images using a customized image processing algorithm in MATLAB that captures fluid regions based on gray scale values and tolerances. The maximum pressure at specific time instants is noted and correlated with fluid slosh images amongst different cases in the test matrix. It is observed that wall pressure increases with an increase in % fill level and velocity. Furthermore, the number and position of baffles has no effect on impact pressure for some specific cases i.e., 90% fill and a velocity of 2 mph. As the fill level increa (open full item for complete abstract)

Committee: Jeremy Seidt (Advisor) Subjects: Design; Fluid Dynamics; Mechanical Engineering; Mechanics

Master of Science (M.S.), University of Dayton, 2014, Mechanical Engineering

The utilization of fuel as a heat sink can allow the design of higher performance aircraft that may normally be limited by heat loads. An energy model for the cross section of a wing with an internal fuel tank in flight is developed for determining its potential use as a heat sink in the conceptual design phase. The computations are aimed at being based more on physical dependencies than empirical correlations. The conservation of energy equation is solved separately using prior calculated information from the conservation of mass and momentum equations. The energy analysis is conducted using a series of control volumes around the airfoil surface with an integral method which can utilize various temperature profiles to model the thermal boundary layer. An unheated starting length followed by an isothermal surface approximates the heated fuel tank as a surface boundary condition. The performance of explicit and implicit methods for solving the resulting set of energy equations is compared with the implicit method proving to function more desirably. The implemented method is verified through analyzing the effects of refining the discretization along the surface as well as normal to it. Also, a flat plate analysis is compared to NACA 0001 airfoil results to demonstrate that XFOIL is coupled correctly with the program to enable computing flow information over arbitrary airfoils. Results of the developed method are compared to empirical correlations for validation purposes involving turbulent flow test cases over NACA 0001, NACA 0007, and NACA 0015 airfoils. The calculations are first conducted for a completely isothermal surface and then for an unheated starting length to isothermal surface. Four temperature profiles are initially considered, but are narrowed down to two profiles for the majority of the results. When modeling a fuel tank as a heat source using an unheated starting length to isothermal surface boundary condition, the results show reasonable agreement wit (open full item for complete abstract)

Committee: Markus Rumpfkeil Ph.D. (Advisor); Aaron Altman Ph.D. (Committee Member); José Camberos Ph.D., P.E. (Committee Member) Subjects: Aerospace Engineering; Engineering; Mechanical Engineering

MS, University of Cincinnati, 2006, Engineering : Aerospace Engineering

An investigation into the dynamics of liquid in an enclosed container experiencing low frequency, small amplitude roll oscillations was performed. Previous research suggests that under dynamic conditions can decrease the lower flammability limit; however characterization of the fluid dynamics in these tests was not performed. This study examined these dynamics by utilizing a motion simulator and a 2.1 m3 capacity rectangular tank. Water depths of 0.265 m, 0.371 m, and 0.530 m were examined. The tank experienced a two dimensional roll oscillation at frequencies between 0.25 Hz to 0.45 Hz at oscillation amplitudes of 2.42°, 3.50°, and 4.71°. The formation of a hydraulic jump was observed at tank oscillations near the resonance frequency of the liquid volume and the formation of these jumps occurred at the frequency, but out of phase, of the driven tank oscillation. At lower frequencies, wave/wave interactions were observed that caused spray formation in specific locations of the tank ullage.

Committee: Dr. Peter Disimile (Advisor) Subjects:

Master of Science (MS), Ohio University, 2007, Mechanical Engineering (Engineering)

Use of hydrogen as an automotive fuel has been successfully demonstrated for the use but they are not ready for consumers yet. One of the major problems associated with the use of hydrogen as an automotive fuel is the storage of hydrogen on-board. Hydrostatic Pressure Retainment (HPR) is an innovative gaseous storage concept which consists of a number of small hollow spherical bubbles arranged within a solid mass similar to a sponge-like structure. These spherical bubbles or the inner-matrix can be arranged in similar fashion as the three basic packing structures of crystalline metals: Simple Cubic (SC), Body Centered Cubic (BCC) and Face Centered Cubic (FCC). In a HPR vessel, suitable configuration for the inner-matrix and feasibility study of different materials is a crucial design step. This thesis investigates the feasibility of different materials for inner-matrix using an ideal BCC microstructure and also achieves one of the milestones of the HPR research by finding and analytically supporting the suitable configuration for the HPR inner-matrix, using Finite Element Analysis.

Committee: Hajrudin Pasic (Advisor) Subjects:

Master of Science (MS), Ohio University, 2006, Mechanical Engineering (Engineering)

Studies have proven hydrogen gas as a highly efficient, renewable and alternative energy source and it is expected to serve as a common fuel for all mobile and stationary applications. However, currently the on-board storage difficulties prevent the practical usage of hydrogen in automotive applications. A more efficient and innovative method of hydrogen storage for automotive fuel cell application is to compress hydrogen in minute hollow spherical bubbles incorporating the Hydrostatic Pressure Retainment (HPR) technology. In a HPR vessel, the material properties and the inner matrix structure are two critical design parameters that determine the hydrogen mass efficiency. The focus of this study is devoted to investigating the performance characteristics of one configuration; spherically shaped bubbles homogenously arranged in a simple cubic inner matrix packing structure for a HPR vessel, using Finite Element Analysis.

Committee: Hajrudin Pasic (Advisor) Subjects: Engineering, Mechanical

Master of Science (MS), Ohio University, 2004, Mechanical Engineering (Engineering)

There is a great deal of attention being concentrated on reducing the weight of pressure vessels and fuel/oxidizer tanks (tankage) by 10% to 20%. Most efforts are focused at the use of new lighter weight high strength materials to achieve this goal. This author proposes another approach called Hydrostatic Pressure Retainment™ (HPR™) which has the potential of reducing tank weights by nearly 40% while simultaneously increasing safety and design versatility. HPR™ is an original invention of the author and his advisor, and represents a truly novel approach to light weight pressure vessel design. Described herein are the initial steps towards development of this new technology.

Committee: Bhavin Mehta (Advisor) Subjects: Engineering, Mechanical