Drinking water distribution networks such as South East Water Ltd. (SEWL), Melbourne Water, Sydney Water, etc. are supposed to transport only dissolved matter rather than a few visible particles. However, it is almost impossible to make the drinking water free from suspended solid particles. The ability to determine the origins of these particles varies between different water supply systems, with possible sources being from catchment, treatment processes, biofilm growth within the water supply pipes, and corrosion products. Improvement of our understanding of the complex hydrodynamic behavior of suspended and/or deposited particles involved in these distribution pipe networks requires mathematical and physical models. Computational Fluid Dynamics (CFD) along with analytical turbulent model is one of the most popular mathematical techniques, which has the ability to predict the behavior of complex flows for such multiphase flow applications. This study has been completed mainly in two steps. A CFD investigation was carried out to predict the hydrodynamic behavior of turbid particle flowing through a horizontal pipe networks including loop consist of bends and straight pipes. Furthermore, an extended analytical model was re-developed for the liquid-solid system to look at the similar behavior of the solid particles flowing in a turbulent field. These two parallel studies will provide better understandings about the turbidity spikes movements in the distribution networks. A comprehensive CFD investigation was carried out for particle deposition in a horizontal pipe loop consisting of four 900 bends in a turbulent flow field. A satisfactory agreement was established with the experimental data as validation. This was a steady state multi-particle problem, which helped to understand the deposition characteristics for different particle sizes and densities at upstream and downstream sides of the bends as well as its circumference. Particle concentration was seen high at the bottom wall in the pipe flow before entering the bends, but for the downstream of bend the deposition was not seen high at the bottom as seen in upstream of bend rather inner side of the bend wall (600 skewed from bottom). The larger particles clearly showed deposition near the bottom of the wall except downstream. As expected, the smaller particles showed less tendency of deposition and this was more pronounced at higher velocity. Due to the high stream line curvature and associated centrifugal force acting on the fluid at different depths the particles became well mixed and resulted in homogeneous distribution near the bend regions. The hydrodynamic behavior of particles flowing in a turbulent unsteady state flowing through a horizontal pipe was also studied to compare with the drinking water distribution networks data. In this numerical simulation six different flow-profiles and particle-load profiles were used to compute particles deposition and re-entrainment into the systems and to identify the conditions of the deposition and suspension mechanisms. Results showed that after a certain length of pipe and period of time after downward velocity gradient, when the velocity was constants over time, the shear stress was sufficiently high enough to cause the particle deposition on and roll along the bottom wall of pipe wall and created a secondary group of particle peak (called kink). Finally, an extended analytical Turbulent Diffusion Model for liquid-solid phase was developed following an existing gas-liquid turbulence model. This turbulent diffusion model was then compared with the results of the CFD investigation making use of the same boundary conditions. The comparison established good agreement between these two models. The influence of velocity on the particle size distribution was dominant over the influence of the superficial liquid velocity, which was also explained by using the new parameter, velocity ratio. This velocity ratio was defined as the ratio between the free flight and gravitational velocity. Due to some inevitable assumptions used in the analytical model, the results showed typically less deposition as compared with the CFD investigation.

The progressing cavity pump is a type of positive displacement pump that is capable of moving nearly any fluid. This type of pump transports fluids in a series of discrete cavities formed by the helical geometries of its rigid rotor and elastomeric stator. With appropriate materials for the rotor and stator, this pump can move combinations of liquids, suspended solids, and gasses equally well. Because of its versatility, the progressing cavity pump is widely used in the oil industry to transport mixtures of oil, water, and sediment; this investigation was prompted by a desire to extend the use of progressing cavity pumps to wet gas pumping applications. One of the progressing cavity pump's limitations is that the friction between the rotor and stator can generate enough heat to damage the rotor if the pump is not lubricated and cooled by the process fluid. Conventional wisdom dictates that this type of pump will overheat if it pumps only gas, with no liquid in the process fluid. If a progressing cavity pump is used to boost the output from a wet gas well, it could potentially be damaged if the well's output is too dry for an extended period of time. This project seeks to determine how a progressing cavity pump behaves when operating at gas volume fractions between 0.90 and 0.98. A progressing cavity pump manufactured by seepex, model no. BN 130-12, is tested at half and full speed using air-water mixtures with gas volume fractions of 0.90, 0.92, 0.94, 0.96, and 0.98. The pump's inlet and outlet conditions are controlled to produce suction pressures of 15, 30, and 45 psi and outlet pressures 0, 30, 60, 90, 120, and 150 psi higher than the inlet pressure. A series of thermocouples, pressure transducers, and turbine flow meters measures the pump's inlet and outlet conditions, the flow rates of water and air entering the pump, and pressures and temperatures at four positions within the pump's stator. Over all test conditions, the maximum recorded temperature of the pump stator did not exceed the maximum safe rubber temperature specified by the manufacturer. The pump’s flow rate is independent of both the fluid's gas volume fraction and the pressure difference across the pump, but it increases slightly with the pump's suction pressure. The pump's mechanical load, however, is dependent only on the pressure difference across the pump and increases linearly with that parameter. Pressure measurements within the stator demonstrated that the leakage between the pump's cavities increases with the fluids gas volume fraction, indicating that liquid inside the pump improves its sealing capability. However, those same measurements failed to detect any appreciable leakage between the two pressure taps nearest the pump's inlet. This last observation suggests that the pump could be shortened by as much as 25 percent without losing any performance in the range of tested conditions; shortening the pump should increase its efficiency by decreasing its frictional mechanical load.

The development of a cost-effective multiphase flow meter to determine the individual phase flow rates of oil, water and gas was investigated through the exploitation of a single clamp-on gamma densitometer and signal processing techniques. A fast-sampling (250 Hz) gamma densitometer was installed at the top of the 10.5 m high, 108.2 mm internal diameter, stainless steel catenary riser in the Cranfield University multiphase flow test facility. Gamma radiation attenuation data was collected for two photon energy ranges of the caesium-137 radioisotope based densitometer for a range of air, water and oil flow mixtures, spanning the facility’s delivery range. Signal analysis of the gamma densitometer data revealed the presence of quasi-periodic waveforms in the time-varying multiphase flow densities and discriminatory correlations between statistical features of the gamma count data and key multiphase flow parameters. The development of a mechanistic approach to infer the multiphase flow rates from the gamma attenuation information was investigated. A model for the determination of the individual phase flow rates was proposed based on the gamma attenuation levels; while quasi-periodic waveforms identified in the multiphase fluid density were observed to exhibit a strong correlation with the gas and liquid superficial phase velocity parameters at fixed water cuts. Analysis of the use of pattern recognition techniques to correlate the gamma densitometer data with the individual phase superficial velocities and the water cut was undertaken. Two neural network models were developed for comparison: a single multilayer-perceptron and a multilayer hierarchical flow regime dependent model. The pattern recognition systems were trained to map the temporal fluctuations in the multiphase mixture density with the individual phase flow rates using statistical features extracted from the gamma count signals as their inputs. Initial results yielded individual phase flow rate predictions to within ±10% based on flow regime specific correlations.

No description available.

Supersaturated water injection (SWI) is a novel remediation technology which is able to remove entrapped residual NAPLs from saturated porous media by both volatilization (partitioning of volatile contaminants into the gas phase) and mobilization (displacement of isolated NAPL residuals by gas clusters). The character of gas saturation evolution in-situ in saturated porous media during SWI results in high sweep efficiency. This work focuses on studying the recovery of entrapped residual NAPL by the mobilization mechanism during SWI, thus low-volatility NAPL residuals, kerosene and a kerosene-hexadecane mixture, are used as contaminants. A series of SWI recovery experiments are conducted to investigate the influence of grain size, low-permeability layering, and physical properties of the contaminants on the recovery behavior. For columns contaminated with kerosene, the residual saturation can be reduced to around 4% from an initial value of 16%, and over 70% of the residual kerosene is recovered by a combination of mobilization and volatilization in homogeneous sand packs. For columns contaminated with a kerosene-hexadecane mixture, the final residual saturation is 7.4% and the final NAPL recovery is lower than that in kerosene columns. Grain size has little influence on NAPL recovery, but low permeability layering has a significantly negative influence. Experiments designed to compare SWI to sparging, and water-gas co-injection showed that water-gas co-injection was able to effectively recovery residual NAPLs albeit not as efficiently as SWI, while steady gas sparging is completely ineffective at recovering residual NAPL by mobilization. Based on these experimental observations, a conceptual model, involving double displacements and NAPL bank formation, is purposed to explain the experimental observations.

Water-in-oil (W/O) emulsions consist of water droplets dispersed in continuous oil phase. They are encountered at various stages of oil production. The oil produced from an oil-well usually carries a significant amount of water in the form of droplets. In enhanced oil recovery techniques involving the injection of polymer solution, the aqueous phase of the water-in-oil emulsions produced from the oil well consists of polymeric additive. A good understanding of the flow behavior of emulsions in pipelines is essential for the design and operation of oil production-gathering facilities and emulsion pipelines. A number of studies have been reported on simultaneous flow of oil and water in pipelines. However, the studies reported in the literature are mainly focused on either oil-water flow patterns and separated flows (annular and stratified flow of oil and water phases) or oil-in-water (O/W) emulsion flows. The pipeline flow of water-in-oil (W/O) emulsions has received less attention. Also, little work has been carried out on the effect of additives such as polymer. In this study, new experimental results are presented on the pipeline flow behavior of water-in-oil (W/O) emulsions, with and without the presence of polymeric additive in the aqueous phase. The emulsions were prepared from three different oils, namely EDM-244, EDM-Monarch, and Shell Pella of different viscosities (2.5 mPa.s for EDM-244, 6 mPa.s for EDM-Monarch, and 5.4 mPa.s for Shell Pella, at 25 0C). The water-in-oil emulsions prepared from EDM-244 and EDM-Monarch (without any polymeric additive in the dispersed aqueous phase) exhibited drag reduction behavior in turbulent flow. The turbulent friction factor data of the emulsions fell well below the standard Blasius equation for smooth pipes. The water-in-oil emulsions prepared from EDM-244 exhibited stronger drag reduction as compared with the EDM-Monarch emulsions. The Shell Pella emulsions (w/o type) did not exhibit any drag reduction in turbulent flow; the friction factor data followed the Blasius equation. The Shell Pella emulsions were more stable than the EDM-244 and EDM-Monarch emulsions. When left unstirred, the EDM-244 and EDM-Monarch emulsions quickly coalesced into separate oil and water phases whereas the Shell Pella emulsions took significantly longer time to separate into oil and water phases. The Shell Pella oil emulsions were also milkier than the EDM emulsions. The addition of polymer to the dispersed aqueous phase of water-in-oil emulsions had a significant effect on the turbulent drag reduction behavior. Emulsions were less drag reducing when polymer was present in the aqueous droplets. The effect of surfactant on the pipeline flow behavior of water/oil emulsions was also investigated. The surfactant-stabilized water-in-oil emulsions followed the single phase flow behavior. The presence of surfactant in the emulsions caused the dispersed droplets to become significantly smaller. It is believed that the droplets were smaller than the scale of turbulence when surfactant was present and consequently no drag reduction was observed.

Supersaturated water injection (SWI) is a novel remediation technology which is able to remove entrapped residual NAPLs from saturated porous media by both volatilization (partitioning of volatile contaminants into the gas phase) and mobilization (displacement of isolated NAPL residuals by gas clusters). The character of gas saturation evolution in-situ in saturated porous media during SWI results in high sweep efficiency. This work focuses on studying the recovery of entrapped residual NAPL by the mobilization mechanism during SWI, thus low-volatility NAPL residuals, kerosene and a kerosene-hexadecane mixture, are used as contaminants. A series of SWI recovery experiments are conducted to investigate the influence of grain size, low-permeability layering, and physical properties of the contaminants on the recovery behavior. For columns contaminated with kerosene, the residual saturation can be reduced to around 4% from an initial value of 16%, and over 70% of the residual kerosene is recovered by a combination of mobilization and volatilization in homogeneous sand packs. For columns contaminated with a kerosene-hexadecane mixture, the final residual saturation is 7.4% and the final NAPL recovery is lower than that in kerosene columns. Grain size has little influence on NAPL recovery, but low permeability layering has a significantly negative influence. Experiments designed to compare SWI to sparging, and water-gas co-injection showed that water-gas co-injection was able to effectively recovery residual NAPLs albeit not as efficiently as SWI, while steady gas sparging is completely ineffective at recovering residual NAPL by mobilization. Based on these experimental observations, a conceptual model, involving double displacements and NAPL bank formation, is purposed to explain the experimental observations.

Water-in-oil (W/O) emulsions consist of water droplets dispersed in continuous oil phase. They are encountered at various stages of oil production. The oil produced from an oil-well usually carries a significant amount of water in the form of droplets. In enhanced oil recovery techniques involving the injection of polymer solution, the aqueous phase of the water-in-oil emulsions produced from the oil well consists of polymeric additive. A good understanding of the flow behavior of emulsions in pipelines is essential for the design and operation of oil production-gathering facilities and emulsion pipelines. A number of studies have been reported on simultaneous flow of oil and water in pipelines. However, the studies reported in the literature are mainly focused on either oil-water flow patterns and separated flows (annular and stratified flow of oil and water phases) or oil-in-water (O/W) emulsion flows. The pipeline flow of water-in-oil (W/O) emulsions has received less attention. Also, little work has been carried out on the effect of additives such as polymer. In this study, new experimental results are presented on the pipeline flow behavior of water-in-oil (W/O) emulsions, with and without the presence of polymeric additive in the aqueous phase. The emulsions were prepared from three different oils, namely EDM-244, EDM-Monarch, and Shell Pella of different viscosities (2.5 mPa.s for EDM-244, 6 mPa.s for EDM-Monarch, and 5.4 mPa.s for Shell Pella, at 25 0C). The water-in-oil emulsions prepared from EDM-244 and EDM-Monarch (without any polymeric additive in the dispersed aqueous phase) exhibited drag reduction behavior in turbulent flow. The turbulent friction factor data of the emulsions fell well below the standard Blasius equation for smooth pipes. The water-in-oil emulsions prepared from EDM-244 exhibited stronger drag reduction as compared with the EDM-Monarch emulsions. The Shell Pella emulsions (w/o type) did not exhibit any drag reduction in turbulent flow; the friction factor data followed the Blasius equation. The Shell Pella emulsions were more stable than the EDM-244 and EDM-Monarch emulsions. When left unstirred, the EDM-244 and EDM-Monarch emulsions quickly coalesced into separate oil and water phases whereas the Shell Pella emulsions took significantly longer time to separate into oil and water phases. The Shell Pella oil emulsions were also milkier than the EDM emulsions. The addition of polymer to the dispersed aqueous phase of water-in-oil emulsions had a significant effect on the turbulent drag reduction behavior. Emulsions were less drag reducing when polymer was present in the aqueous droplets. The effect of surfactant on the pipeline flow behavior of water/oil emulsions was also investigated. The surfactant-stabilized water-in-oil emulsions followed the single phase flow behavior. The presence of surfactant in the emulsions caused the dispersed droplets to become significantly smaller. It is believed that the droplets were smaller than the scale of turbulence when surfactant was present and consequently no drag reduction was observed.

A Rail to Rail Differential Control Delay Line using multi-band technology can provide wider range on a delay-locked loop (DLL) is proposed in this thesis. Delay-Locked Loops (DLLs) have been widely used for clock deskew instead of Phase-Locked Loop (PLLs) because of easy design and inherent stable. The main object of this thesis is the description and discussion in Delay-Locked Loop and Rail to Rail Differential Control Delay Line; uses TSMC 0.18£gm 1P6M CMOS process to design a 70 MHz¡ã750 MHz DLL and the supply voltage is 1.8V. This thesis is characterized by utilizing rail to rail input to reduce noise interference and enhance the signal integrity¡]low distortion, low noise, low power and high gain¡^.By the phase selection circuit is used to extend operation frequency. The operate frequency range of DLL is 70MHz to 750MHz, the power consumption of the Entire system is less than 32mW. The phase error is 10 ps at 70MHz and <10 ps at 750MHz in lock. The proposed DLL can provide wider range and lower jitter in this thesis.

Twin-screw multiphase pumps experience a severe decrease in efficiency, even the breakdown of pumping function, when operating under wet gas conditions. Additionally, field operations have revealed significant vibration and thermal issues which can lead to damage of the pump internals and expensive repairs and maintenance. There are limited models simulating the performance of twin-screw pump under these conditions. This project develops a pump-user oriented simulator to model the performance of twin-screw pumps under wet gas conditions. Experimental testing is conducted to verify the simulation results. Based on the simulations, an innovative solution is presented to improve the efficiency and prevent the breakdown of pumping function. A new model is developed based upon a previous Texas A&M twin-screw pump model. In this model, both the gas slip and liquid slip in the pump clearances are simulated. The mechanical model is coupled with a thermodynamic model to predict the pressure and temperature distribution along the screws. The comparison of experimental data and the predictions of both isothermal and non-isothermal models show a better match than previous models with Gas Volume Fraction (GVF) 95% and 98%. Compatible with the previous Texas A&M twin-screw pump model, this model can be used to simulate the twin-screw pump performance with GVF from 0% to 99%. Based on the effect of liquid viscosity, a novel solution is investigated with the newly developed model to improve the efficiency and reliability of twin-screw pump performance with GVF higher than 94%. The solution is to inject high viscosity liquid directly into the twin-screw pump. After the simulations of several different scenarios with various liquid injection rates and injection positions, we conclude that the volumetric efficiency increases with increasing liquid viscosity and injecting liquid in the suction is suggested.