The next generation air breathing engine that would enable an alternative to conventional air travel or suborbital flight is the supersonic ramjet engine (SCRAM) which requires a highly accelerated rate of fuel mixing and combustion. For this type of engine, one of the improvement opportunities lies in the injection of the fuel into the supersonic flow inside the combustor. In order to determine the flow field that develops when a sonic jet of secondary gas is injected into a supersonic free stream, a dedicated test section was developed which was attached to the existing supersonic wind tunnel at the University of Central Florida. A Schlieren system was developed to visualize the associated flow fields and to provide a tool for future high-speed aerodynamic research. Mixing of a cross flow jet with a supersonic free stream is a topic of interest in the field of hypersonic air travel. In addition to a description and analysis of the resultant data, this thesis also serves as a reference for future research and work done with the UCF supersonic wind tunnel and the Schlieren system. The results agree with the literature, and the Schlieren images obtained show the associated shock and flow structures that are expected with a jet in cross flow.

The mineral processing industry has commonly utilized hydraulic separators throughout history for classification and gravity concentration of various minerals. More commonly referred to as hindered-bed or fluidized-bed separators, these units make use of differential particle settling rates to segregate particles according to shape, size, and/or density. As with any equipment, there are inefficiencies associated with its operation, which prompted an industry driven research program to further evaluate two novel high-efficiency hindered bed separators. These units, which are commercially called the CrossFlow separator and HydroFloat separator, have the potential to improve performance (separation efficiency and throughput) and reduce operating costs (power consumption, water and reagent usage). This thesis describes the results of recent laboratory and pilot-scale tests conducted with the CrossFlow and HydroFloat separators at several locations in the minerals and coal industries. Details of the testing programs (equipment setup, shakedown testing and detailed testing) associated with four coal plants and two phosphate plants are summarized in this work. In most of these applications, the high-efficiency units proved to provide a higher quality product at reduced costs when compared against the performance of conventional separators. As a result of this test work performed in this study, a full-scale CrossFlow separator is being installed at an industrial site. The separator is an integral part of an ultra-fine phosphate recovery system at a Florida processing plant. The unit will be used to classify the +400 mesh material prior to column flotation. The successful implementation of the ultra-fine phosphate recovery system will increase industry profits by the millions of dollars in addition to reducing tailing impoundments and energy requirements. / Master of Science

No description available.

Internal crossflow is an important element to actual gas turbine blade cooling; however, there are very few studies in open literature that have documented its effects on turbine blade film cooling. Experiments measuring adiabatic effectiveness were conducted to investigate the effects of perpendicular crossflow on a row of 45 degree compound angle, cylindrical film cooling holes. Tests included a standard plenum condition, a baseline crossflow case consisting of a smooth-walled channel, and various crossflow configurations with ribs. The ribs were angled to the direction of prevailing internal crossflow at 45 and 135 degrees and were positioned at different locations. Experiments were conducted at a density ratio of DR=1.5 for a range of blowing ratios including M=0.5, 0.75, 1.0, 1.5, and 2.0. Results showed that internal crossflow can significantly influence adiabatic effectiveness when compared to the standard plenum condition. The implementation of ribs generally decreased the adiabatic effectiveness when compared to the smooth-walled crossflow case. The highest adiabatic effectiveness measurements were recorded for the smooth-walled case in which crossflow was directed against the spanwise hole orientation angle. Tests indicated that the direction of perpendicular crossflow in relation to the hole orientation can significantly influence the adiabatic effectiveness. Among the rib crossflow tests, rib configurations that directed the coolant forward in the direction of the mainstream resulted in higher adiabatic effectiveness measurements. However, no other parameters could consistently be identified correlating to increased film cooling performance. It is likely that a combination of factors are responsible for influencing performance, including internal local pressure caused by the ribs, the internal channel flow field, jet exit velocity profiles, and in-hole vortices. / text

This thesis is concerned with the study of different effects in protein ultrafiltration including device configuration, solution chemistry and membrane charge In the recent and more established literature membrane fouling remains a challenging problem that limits the wider application of ultrafiltration. Thus, investigations which can aid understanding and potentially reduce membrane fouling are of particular interest and in this study the problem has been addressed from several different angles Polyethersulfone membranes were studied at varying pH and two ionic strengths using bovine serum albumm and lysozyme as the model proteins. The study was conducted both in a stirred cell and a crossflow configuration in order to evaluate the influence of different system hydrodynamics on filtration This work was further substantiated through the application of filtration models An attempt was also made to modify the membrane surface by low temperature plasma modification with the intention to preferentially alter the characteristics of the membrane surface Both unmodified and plasma-modified polyethersulfone membranes were characterised using a range of analytical methods including flux data, streaming potential, contact angle and MWCO measurements to aid results interpretation. The research showed that MWCO data quoted by manufacturers is mostly greater than that obtained during laboratory studies The MWCO technique was also used to highlight differences between the unmodified and plasma-modified membranes demonstrating that the modification resulted in a membrane with tighter pores in the lower molecular weight region. Concentration polarisation effects were found to be reduced as a result of the plasmamodification The study of protein filtration at different pH and ionic strengths demonstrated that ionic strength effects were more pronounced than pH effects It was also shown that changes m the ionic strength can be used to alter the degree of protein rejection for the given system concentration polarisation was found to be higher during crossflow filtration compared to stirred cell filtration The thesis adds to existing knowledge in the area of ultrafiltration emphasizing the importance of device configuration, solution chemistry as well as the potential of charged membranes

<div>A sharp, circular 7° half-angle cone was tested in the Boeing/AFOSR Mach-6 Quiet Tunnel</div><div>at 6° angle of attack, extending several previous experiments on the growth and breakdown of</div><div>stationary crossflow instabilities in the boundary layer. </div><div><br></div><div>Measurements were made using infrared</div><div>imaging and surface pressure sensors. Detailed measurements of the stationary and traveling</div><div>crossflow vortices, as well as various secondary instability modes, were collected over a large</div><div>region of the cone.</div><div><br></div><div>The Rod Insertion Method (RIM) roughness, first developed for use on a flared cone, was</div><div>adapted for application to crossflow work. It was demonstrated that the roughness elements were</div><div>the primary factor responsible for the appearance of the specific pattern of stationary streaks</div><div>downstream, which are the footprints of the stationary crossflow vortices. In addition, a roughness</div><div>insert was created with a high RMS level of normally-distributed roughness to excite the naturally</div><div>most-amplified stationary mode.</div><div><br></div><div>The nonlinear breakdown mechanism induced by each type of roughness appears to be</div><div>different. When using the discrete RIM roughness, the dominant mechanism seems to be the</div><div>modulated second mode, which is significantly destabilized by the large stationary vortices. This</div><div>is consistent with recent computations. There is no evidence of the presence of traveling crossflow</div><div>when using the RIM roughness, though surface measurements cannot provide a complete picture.</div><div>The modulated second mode shows strong nonlinearity and harmonic development just prior</div><div>to breakdown. In addition, pairs of hot streaks merge together within a constant azimuthal</div><div>band, leading to a peak in the heating simultaneously with the peak amplitude of the measured</div><div>secondary instability. The heating then decays before rising again to turbulent levels. This nonmonotonic</div><div>heating pattern is reminiscent of experiments on a flared cone and earlier computations</div><div>of crossflow on an elliptic cone.</div><div><br></div><div>When using the distributed roughness there are several differences in the nonlinear breakdown</div><div>behavior. The hot streaks appear to be much more uniform and form at a higher wavenumber,</div><div>which is expected given computational results. Furthermore, the traveling crossflow waves become</div><div>very prominent in the surface pressure fluctuations and weakly nonlinear. In addition there</div><div>appears in the spectra a higher-frequency peak which is hypothesized to be a type-I secondary instability</div><div>under the upwelling of the stationary vortices. The traveling crossflow and the secondary</div><div>instability interact nonlinearly prior to breakdown.</div>

ABSTRACT In this study, two chemical mechanical polishing (CMP) wastewaters were treated by crossflow electro-microfiltration. Also studied are the effects of operation parameters on their treatment efficiencies. In the semiconductor industry, presently, CMP has become the key technique to provide global planarization on interlevel dielectrics (ILD) and metal layers of wafers. In general, the post-CMP cleaning process will produce a great quantity of CMP wastewater. Normally, CMP wastewater consists of abrasives of high concentration and stability, chemicals (e.g., oxidant and surfactant), and a tremendous mass of de-ionized water. Because of the negatively charged suspended solids in CMP wastewater, crossflow electro-microfiltration was used to treat this type of wastewater. By applying an electric field to the system, the negatively charged suspended solids were expelled from the membrane surface moving toward the anode. Not only reducing the cake formation on the membrane, enhancement of the filtration rate and permeate flux have also been found when an external electric field is applied to the filtration system. In this investigation, CMP wastewaters obtained from wafer fabs A and B were first characterized by various standard methods. In CMP wastewater A, the suspended solids were found to have a high negative zeta potential, about ¡V78 mV. Its electrical conductivity was determined to be 127.2 £gS/cm. Before testing, each CMP wastewater was pre-filtered using a filter paper of 1.2 £gm in pore size. An experimental design based on the Taguchi method was employed. The L9 orthogonal arrays were utilized to investigate the effects of four experimental factors ( i.e., electric field strength, crossflow velocity, transmembrane pressure, and membrane pore size) on the filtration rate and permeate quality in the crossflow electro-microfiltration system. When the electric field strength applied was lower than the critical electric field strength, increases of the electric field strength, transmembrane pressure, and membrane pore size were found to be beneficial to the filtration rate. The experimental results were further subjected to the analysis of variance and regular analysis. For both CMP wastewaters A and B, the electric field strength and membrane pore size were determined to be very significant parameters. In this filtration system, the optimal treatment efficiency could be achieved by using a higher electric field strength, lower crossflow velocity, higher transmembrane pressure, and larger membrane pore size. The quality of permeate thus obtained was even better than the tap water quality standards. Therefore, the permeate might be worth recycling for various purposes.

ABSTRACT In this study, two chemical mechanical polishing (CMP) wastewaters were treated by crossflow electro-microfiltration. Also studied are the effects of operation parameters on their treatment efficiencies. In the semiconductor industry, presently, CMP has become the key technique to provide global planarization on interlevel dielectrics (ILD) and metal layers of wafers. In general, the post-CMP cleaning process will produce a great quantity of CMP wastewater. Normally, CMP wastewater consists of abrasives of high concentration and stability, chemicals (e.g., oxidant and surfactant), and a tremendous mass of de-ionized water. Because of the negatively charged suspended solids in CMP wastewater, crossflow electro-microfiltration was used to treat this type of wastewater. By applying an electric field to the system, the negatively charged suspended solids were expelled from the membrane surface moving toward the anode. Not only reducing the cake formation on the membrane, enhancement of the filtration rate and permeate flux have also been found when an external electric field is applied to the filtration system. In this investigation, CMP wastewaters obtained from wafer fabs A and B were first characterized by various standard methods. In CMP wastewater A, the suspended solids were found to have a high negative zeta potential, about ¡V78 mV. Its electrical conductivity was determined to be 127.2 £gS/cm. Before testing, each CMP wastewater was pre-filtered using a filter paper of 1.2 £gm in pore size. An experimental design based on the Taguchi method was employed. The L9 orthogonal arrays were utilized to investigate the effects of four experimental factors ( i.e., electric field strength, crossflow velocity, transmembrane pressure, and membrane pore size) on the filtration rate and permeate quality in the crossflow electro-microfiltration system. When the electric field strength applied was lower than the critical electric field strength, increases of the electric field strength, transmembrane pressure, and membrane pore size were found to be beneficial to the filtration rate. The experimental results were further subjected to the analysis of variance and regular analysis. For both CMP wastewaters A and B, the electric field strength and membrane pore size were determined to be very significant parameters. In this filtration system, the optimal treatment efficiency could be achieved by using a higher electric field strength, lower crossflow velocity, higher transmembrane pressure, and larger membrane pore size. The quality of permeate thus obtained was even better than the tap water quality standards. Therefore, the permeate might be worth recycling for various purposes.

The high cost of energy has resulted in a renewed interest in the study of reducing skin-friction drag in aeronautical applications. Laminar Flow Control (LFC) refers to any technique which alters the basic-state flow-field to delay transition from laminar to turbulent flow. Achieving fully laminar flow over a civilian transport wing will significantly reduce drag and fuel costs while increasing range and performance. Boundary-layer suction has proven to be an effective means of achieving laminar flow over an aircraft wing as demonstrated with the Northrop X-21 program; however, even with the savings in fuel, the high manufacturing and maintenance costs have discouraged the use of this technology. Recent work using threedimensional (3-D) spanwise-periodic distributed roughness elements (DREs) has shown great promise as a means of controlling the crossflow instability responsible for transition over a swept wing without the need for a complex suction system. The Texas A

Produced water is formed in underground formations and brought up to the surface along with crude oil during production. It is by far the largest volume byproduct or waste stream. The most popular preference to deal with produced water is to re-inject it back into the formation. Produced water re-injection (PWRI) needs a treatment before injection to prevent formation blockage. Due to the increase of produced water during oil production in the west of Kuwait, an effluent treatment and water injection plants were established and commissioned in 2004 so that produced water could be used for re-injection purposes. It is estimated that oil wells in the west of Kuwait produce 15 to 40 % of produced water. The main aim of this treatment train is to reduce not only the oil-in-water amount to less than 10 ppm, but also total suspended solids to 5 ppm which is the maximum allowable concentration for re-injection and disposal. Furthermore, with respect to the upper limit for injection, the maximum number of particles between 5 and 8 microns is 200 in 0.1 ml. In practice the number is found to exceed this limit by 10 times...