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The water-soluble polymer PAM (polyacrylamide) is used in enhanced oil recovery (EOR) operations. It is pumped into water injection wells to increase the viscosity of the injected water and in turn to direct more oil towards production wells. This EOR process is proven to be sensitive to operational well conditions such as hydrocarbon reservoir temperature, as well as the salinity of the injected water and/or formation water. These operational conditions lead to technical challenges ranging from the solubility of PAM in injection water to the behaviour of PAM inside the reservoir. To gain a clear picture of the functionality of PAM in EOR applications, this report characterizes its behaviour of in terms of degree of hydrolysis and changes in solution viscosity determined using Perkin Elmer spectrum 100 Fourier transform infrared-Attenuated total reflection (FTIR)-ATR and nuclear magnetic resonance spectroscopy (1H NMR) and a Fann model 35 Couette and Cole Parmer rotational viscometer, respectively. Different shear rates were investigated to determine the effect of shear on PAM gel stability. Experiments were performed for PAM mixed with formation brine at 50, 70, and 90 °C for ageing times of up to 30 days. The results indicate that the degree of hydrolysis achieved after 30 days is much higher in saline solutions than in pure water, and that this effect is more pronounced at higher temperatures. For example, after 30 days at 50 °C, the hydrolysis level was observed to be 53%, rising to 65% at 70 °C and 75% at 90 °C in PAM mixed with brines. Similar trends were observed with viscosity, where lower viscosity was observed for samples at higher temperatures and salinities. It is thus reasonable to conclude that the degree of hydrolysis causes changes in the viscosity of the polymer gel, leading to a decline in its performance as it ages.

Microbubble (MB) technology constitutes a suite of promising low-cost technologies with potential applications in various sectors. Microbubbles (MBs) are tiny gas bubbles with diameters in the micrometre range of 10–100 μm. Along with their small size, they share special characteristics like slow buoyancy, large gas–liquid interfacial area and high mass-transfer efficiency. Initially, the review examines the key dissimilarities among the different types of microbubble generators (MBG) towards economic large-scale production of MBs. The applications of MBs to explore their effectiveness at different stages of wastewater treatment extending from aeration, separation/ flotation, ozonation, disinfection and other processes are investigated. A summary of the recent advances of MBs in real and synthetic wastewater treatment, existing research gaps, and limitations in upscaling of the technology, conclusion and future recommendations is detailed. A critical analysis of the energetics and treatment cost of combined approaches of MB technology with other advanced oxidation processes (AOPs) is carried out highlighting the potential applicability of hybrid technology in large-scale wastewater treatment.

In this paper, the effect of using different configurations of absorber plate, including one line finned flat absorber and two lines finned absorber plate, on the thermal performance of a flat plate – double passing solar air heater was investigated experimentally. L- shape fins are soldered on the absorber plate to roughen the absorber plate and generate vortices to enhance the heat transfer between the working fluid (air) and absorber plate to improve the thermal efficiency. The outdoor experimental test was carried out during February and May under the weather conditions of Baghdad city (Longitude 33.3 N and Latitude 44.44 E). The results show that the air temperature is 48 ℃, 47.5 ℃, and 58.5 ℃ at an air velocity of 1.7 m/s for a single line of fins which increased to 52 ℃, 57.5 ℃, and 66 ℃ at air velocity of 0.9 m/s for two lines of fins. The efficiency is increased by 28% for one line of fins and 66% for two lines of fins at an air velocity of 0.9 m/s while increased by 27% for one line of fins and 51% for two lines of fins at an air velocity of 1.7 m/s. The average exergy destruction rate increases by 37.6%, 60.6%, and 68.66% for the absorber plate, working fluid, and glass cover, respectively, for velocity increase from 0.9 m/s to 1.9 m/s. The exergy efficiency increased by 24.1% when the velocity increased from 0.9 m/s to 1.9 m/s.

Microbubble generators are of considerable importance to a range of scientific fields from use in aquaculture and engineering to medical applications. This is due to the fact the amount of sea life in the water is proportional to the amount of oxygen in it. In this paper, experimental measurements and computational Fluid Dynamics (CFD) simulation are performed for three water flow rates and three with three different air flow rates. The experimental data presented in the paper are used to validate the CFD model. Then, the CFD model is used to study the effect of diverging angle and throat length/throat diameter ratio on the size of the microbubble produced by the Venturi-type microbubble generator. The experimental results showed that increasing water flow rate and reducing the air flow rate produces smaller microbubbles. The prediction from the CFD results indicated that throat length/throat diameter ratio and diffuser divergent angle have a small effect on bubble diameter distribution and average bubble diameter for the range of the throat water velocities used in this study.

In this paper, we analyse the effectiveness of microbubble technology in inactivating/reducing gram-negative, gram-positive, and radiation-resistant bacteria, including Escherichia coli, Bacillus subtilis, and Deinococcus radiodurans, respectively, in model water. Key water quality parameters such as dissolved oxygen, conductivity, pH, and total dissolved solids are recorded and presented to demonstrate their range in the current investigation. The study results indicate a reduction of 95% in E. coli, 100% in D. radiodurans, and 45% in B. subtilis following microbubble treatment. These findings suggest that ambient air microbubbles, generated using a low-cost, reagent-free, and eco-friendly venturi-type microbubble generator, represent a promising technique for reducing bacterial loads in water.

Accurate visualization of bubbles in multiphase flow is a crucial aspect of modeling heat transfer, mixing, and turbulence processes. It has many applications, including chemical processes, wastewater treatment, and aquaculture. A new software, Flow_Vis, based on experimental data visualization, has been developed to visualize the movement and size distribution of bubbles within multiphase flow. Images and videos recorded from an experimental rig designed to generate microbubbles were analyzed using the new software. The bubbles in the fluid were examined and found to move with different velocities due to their varying sizes. The software was used to measure bubble size distributions, and the obtained results were compared with experimental measurements, showing reasonable accuracy. The velocity measurements were also compared with literature values and found to be equally accurate.

Liquivac pumps, with their unique shaped twin start helical rotor, have found utility in various sectors but the major drawback limiting in their global exploitation is their low performance. This paper investigates the study of performance of the Liquivac pump produced by Tomlinson Hall Ltd. Experimental data was used to validate a numerical model developed in Ansys Fluent 20.2 for the Liquivac pump. Four different geometric models of the rotor were tested numerically to find the optimum design using blade number and pitch length as the criteria to achieve improved efficiency. The choice of turbulence model is an important factor in the most accurate prediction with computational fluid dynamics (CFD) simulation. Four different turbulence models were validated with experimental measurements. The realizable K-ε model gave the most accurate performance predictions with a relative deviation of 3.8%. So, the realizable K-ε model was employed for further parametric optimization of the rotor. The results indicate a reasonable improvement in the head and efficiency of the Liquivac pump with a new rotor geometry of four equidistant blades in the front, back and four flights with 30 mm pitch. This is attributed to the most favourable balance between the different losses and most guided and uniform flow inside the rotor channels.

The aim of this paper is to produce and validate a simulated model of the external flow around the NACA 2412 using ANSYS Fluent; utilising experimental data for a low velocity case (20.73 m/s) from literature. This model will be subsequently used to produce data for a high velocity case (272.1 m/s, Mach = 0.8) which is the practical velocity for commercial aircraft. Both an infinite aspect ratio wing (2D) and a finite aspect ratio wing (3D) will be the subjects of this investigation. Experimental data on which the simulated models will be compared and hence validated is taken from Jacobs et al. [1]. This experimental data contains both a finite aspect ratio wing and an infinite aspect ratio wing. An accurate simulation model of the external flow around a wing will be beneficial in the visualisation of the flow; particularly in the investigation of the onset of a stall and the aerodynamic characteristic differences between the wing root and wing tip. The model will also provide simulated data of an external flow condition of which no experimental data currently exists. Finally, value will be gained in the investigation between the differences of an external flow around a 2-dimensional (2D) wing versus a 3-dimensional (3D) wing. All simulations exhibited flow physics consistent with those seen in experimental data; further validating the results. A detailed methodology has been provided with a view that new data becomes available for this aerofoil and wing geometry. Considering the aerofoil simulation, incredible accuracy has been achieved. However, with regards to the wing simulation, further work is required to identify the issue which resulted in a lower lift curve slope when compared to the experimental data.

In modern Computational Fluid Dynamic (CFD) Analysis of Convergent-Divergent (C-D) Nozzles, current research has shown that, it is common practice to use either experimental or analytical results to predict the accuracy of the CFD models by comparison of the results. It is also commonly agreed, amongst the literature reviewed, that the CFD modelling software packages available do not accurately model turbulence for applications such as transonic C-D nozzles. This study aims to develop a theoretical approach for calculation of flow properties along the axis of the C-D nozzle based on the fundamental gas dynamic equations. The theoretical analyses is validated by experimental data. Then, the CFD model is used to simulate the experimental cases which are compared with the data from both theoretical analysis and experimental measurements. Then, the validated CFD model can be used for more complex analyses, representing more elaborate flow phenomena such as internal shockwaves and boundary layers. The geometry used in the analytical study and CFD simulations constructed to model the experimental rig. The [1, 2] analytical study is undertaken using isentropic and adiabatic relationships and the output of the analytical study, the 'shockwave location tool', is created. The results from the analytical study are then used to optimise the redesign an experimental rig to for more favorable placement of pressure taps and gain a much better representation of the shockwaves occurring in the divergent section of the nozzle. The results from the CFD model can then be directly compared other results in order to gauge the accuracy of each method of analysis. The validated model can then be used in order to create several, novel nozzle designs which may offer better performance and ease of manufacture and may present feasible improvements to existing high-speed flow applications.