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Investigation Of Formation And Applications Of High-Speed Liquid Projectiles, Oleg Petrenko Dec 2006

Investigation Of Formation And Applications Of High-Speed Liquid Projectiles, Oleg Petrenko

Dissertations

The work comprises experimental and numerical studies of generation and application of high-speed liquid projectiles. Numerical models were created for a projectile formation by two kinds of launchers, water extruder and water cannon. In the water extruder the kinetic energy of a fast moving piston is transferred to the water load and extrudes the load at a high speed. By contrast in the water cannon the water load itself accumulates the kinetic energy from the expanding combustion gasses. Then, in the course of water motion through the converging nozzle the energy is redistributed between head and tail of the projectile ...


Flow Characteristics And Phase Interactions Of Evaporating Sprays In Gas-Solid Suspensions, Muhammad Mushahid Rafique Qureshi Dec 2006

Flow Characteristics And Phase Interactions Of Evaporating Sprays In Gas-Solid Suspensions, Muhammad Mushahid Rafique Qureshi

Dissertations

Evaporating spray jets have a wide range of applications in many industrial processes such as fluidized catalytic cracking of crude oil in petroleum refinery, coal gasification, fluidized coking to make synthetic crude oil, and condensed mode gas polymerization. The rapid evaporation of spray jets significantly affects the gas-solids mixing, solids concentration, gas/solids temperature and gas/solids velocity acceleration. The complex interactions mechanism of phase change, three phase interaction, heat and mass transfer of gas, solids and evaporating droplets dominate the process efficiency and product quality. In such three-phase flows, the phase transport characteristics are influenced by both droplet-gas interaction ...


Nanoparticle Formation And Coating Using Supercritical Fluids, Abhijit Aniruddha Gokhale Dec 2006

Nanoparticle Formation And Coating Using Supercritical Fluids, Abhijit Aniruddha Gokhale

Dissertations

Jet breakup phenomenon and nanoparticle formation

The focus of this dissertation is to study the SAS process to manufacture nanoparticles with minimum agglomeration, controlled size and size distribution. Solution jet breakup and solvent evaporation into supercritical fluid (SC CO2) is studied using high speed charged coupled device (CCD) camera facilitated with double shot particle image veloimetry (PIV) laser and a high pressure view cell. Particles formation using SAS is studied. Polyvinylpyrrolidone (PVP) particles are formed using micron size capillary nozzles and combination of thermodynamically good and poor solvents in order to achieve nano-sized particles with reduced agglomeration and narrow ...


Constitutive Modeling Of The Thermo-Mechanics Associated With Crystallizable Shape Memory Polymers, Gautam Barot Aug 2006

Constitutive Modeling Of The Thermo-Mechanics Associated With Crystallizable Shape Memory Polymers, Gautam Barot

Dissertations

This research addresses issues central to material modeling and process simulations. Here, issues related for developing constitutive model for crystallizable shape memory polymers are addressed in details. Shape memory polymers are novel material that can be easily formed into complex shapes, retaining memory of their original shape even after undergoing large deformations. The temporary shape is stable and return to the original shape is triggered by a suitable mechanism such heating the polymer above a transition temperature. Crystallizable shape memory polymers are called crystallizable because the temporary shape is fixed by a crystalline phase, while return to the original shape ...


Effect Of Polymorphic Phase Transformations Within An Alumina Layer On The Ignition Of Aluminum Particles, Mikhaylo Aleksiyovych Trunov May 2006

Effect Of Polymorphic Phase Transformations Within An Alumina Layer On The Ignition Of Aluminum Particles, Mikhaylo Aleksiyovych Trunov

Dissertations

Experimental measurements of aluminum ignition temperature and models used to describe aluminum ignition are reviewed. It is shown that the current models cannot describe ignition of aluminum powders of different sizes and ignited under various experimental conditions. The properties of and phase changes occurring in the alumina scale existing on the surface of aluminum particles at different temperatures are systematically studied. The mechanism of aluminum oxidation is quantified and a new simplified ignition model is developed.

Thermogravimetry was used to study the oxidation of aluminum powders of various particle sizes and surface morphologies in oxygen at temperatures up to 1500 ...


Synthesis And Characterization Of Mechanically Alloyed Aluminum-Based Compounds As High Energy Density Materials, Xiaoying Zhu May 2006

Synthesis And Characterization Of Mechanically Alloyed Aluminum-Based Compounds As High Energy Density Materials, Xiaoying Zhu

Dissertations

A new type of metastable reactive powders for potential use as high energy density materials in propellants, explosives, and pyrotechnics was developed. These powders are intended to replace aluminum typically added to energetic formulations to increase reaction enthalpy and temperature. The new materials are metastable aluminum-based alloys, which enable achievement of substantially reduced ignition temperatures and accelerated bulk burn rates compared to aluminum. Titanium and lithium were used as alloying components. The materials properties and characteristics leading to their enhanced combustion performance were investigated. The powders were prepared using mechanical alloying and characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy ...