Engineering Commons^™

Studies On Microscopic Flow Structure Inside A Rectangular Circulating Fluidized Bed Through Image Analysis, Jingsi Yang

Electronic Thesis and Dissertation Repository

The microscopic flow structure is studied systematically and comprehensively through a visualization system in a narrow rectangular circulating fluidized bed (CFB) transparent Plexiglas riser with a height of 7.6 m and a cross section of 19 mm × 114 mm. A visualization system consisting of a high-speed video camera, a light source, and image processing and analyzing programs is designed and developed to enable the flow structure to be visualized directly and studied quantitatively. FCC particles of 67 μm are used as the bed materials under different operating conditions with superficial gas velocity (U_g) and solids circulation rate …

Hydrodynamics In Recirculating Fluidized Bed Mimicking The Stripper Section Of The Fluid Coker, Francisco J. Sanchez Careaga

Electronic Thesis and Dissertation Repository

The stripper section of a Fluid Coker^TM consists of a system of baffles (sheds) that enhances the removal of interstitial and adsorbed hydrocarbon vapors from the fluidized coke-particles. Most of the hydrocarbon-vapors released below a stripper shed flow up to the stripper shed, where they may crack and form coke deposits that foul the shed. Extensive fouling changes the shapes of the sheds, makes them thicker and reduces the free-space between the adjacent sheds until downward solids flow is so impaired that the Coker has to be shut down.

The Radioactive Particle Tracking (RPT) technique allows the determination of …

The Onset Of Purely Elastic And Thermo-Elastic Instabilities In The Taylor-Couette Flow: Influence Of Gap Ratio And Fluid Thermal Sensitivity, Mohammadreza Ghanbari

Masters Theses

Linear stability analysis of Taylor-Couette flow of dilute polymeric solutions has been performed by using two prototypical constitutive equations for polymeric solutions namely, the Oldroyd-B and the FENE-P models. The hydrodynamic stability characteristics of the flow in presence and absence of thermal effects and in the limit of vanishing fluid inertia have been determined using an eigenvalue analysis. Particular attention has been paid to accurate determination of the instability onset conditions as a function of fluid thermal sensitivity and gap ratio. We observe a reduction in the critical Deborah, Dec for the instability onset as the gap ratio and fluid …

Oil-In-Water Emulsification Using Oscillatory Micro-Screen, Jiangshan Liu

Electronic Thesis and Dissertation Repository

A novel emulsification technique has been developed for high throughput production of uniform emulsion droplets using high porosity oscillating stainless steel wire woven micro-screen. Different surfactants were investigated including dispersed/continuous bi-surfactant systems using Span80/SDS and Span80/Tween20. The effects of oscillation amplitude and frequency as well as the dispersed phase flux on emulsion average droplet size and uniformity were investigated. It was found that the droplet average size decreased with increasing the surface sheer stress. The emulsion droplet uniformity determined using the coefficient of variation (CV) changed with oscillations such that there was an optimal oscillating frequency for each amplitude where …