flow pattern

To reduce water production from oil and gas reservoirs, it is necessary to block certain fractures and layers of hydrocarbon formations. Although polymer gels are employed as water shut-off agents to reduce water production, they face challenges due to inefficiencies. This study aims to examine silicate-polymer gels, based on the factors influencing the formation of gel by focusing on controlling the gelation time of the silicate-polymer gelants at various temperatures and investigating the stability of gels. An experimental design was conducted based on 5 levels and 2 parameters, where these two parameters are the concentration of the polymer ranging from 0.06% to 0.3% by weight and the temperature ranging from 20 to 100 degrees Celsius in the presence of a crude oil from the southwest of Iran. Experimental results indicated that citric acid successfully covered the ions and effectively controlled the gelation time. Sodium silicate proved to be one of the main components, along with formation water, citric acid to mitigate the impact of formation ions on the gelation time, and the polymer itself. The presence of formation water led to an increase in gel strength and a decrease in the gelation time. Moreover, elevated temperatures resulted in shorter gelation times and lower viscosity in the polymer gel. Doubling the concentration of the polymer reduced the gelation time by 43%, while a two-fold increase in temperature decreased it by 54%. Increasing the concentration of the polymer indicated a decrease in the gelation time, and an increase in both gel strength and gel viscosity.

This study presents a computational fluid dynamics (CFD) simulation of two-phase flow patterns in a Y-shaped microfluidic device. The two-phase flow of water and n-butyl acetate is simulated using the volume of fluid (VOF) method in a Y-shaped microfluidic device with different flow rates. A 2D model was used for simulation, and the results were compared to experimental data, showing good consistency. The study also examined the effects of organic (n-butyl acetate) and flow on the overall flow model. The authors observe three different flow patterns, including slug flow, parallel flow, and droplet flow, depending on the flow rate. The results indicate that a slug flow pattern is detected when the flow rates of the aqueous and organic phases are both low and similar. Nonetheless, as the overall flow rate rises, the slug flow pattern shifts to either parallel droplet or plug flow. Similarly, when the flow rate of the aqueous phase is increased while keeping the organic phase flow rate constant, the shift occurs from slug flow to droplet flow. Therefore, this study is significant in providing insights into the different flow regimes that can occur in a microfluidic system. This understanding can be used to design and optimize microfluidic devices for a variety of applications.

Several theoretical approaches for predicting performance parameters (collection efficiency, pressure drop, and velocities) of cyclone separators have been developed due to their extensive use in particle handling industries. Expensive and time-consuming experiments to analyze the swirling flow inside the cyclone separators could be avoided with reliable theoretical approaches. However, there are only a limited number of cyclone theory evaluations in the literature. This study investigated the accuracy of cyclone theories by comparing experimental and numerical data at a particle loading rate of 1.0 g.m-3 operating at 5 and 10 m.s-1. General agreements between the theories were revealed by Muschelknautz’s theory for collection efficiency and Shepherd and Lapple’s theory for pressure variations at low solid loading conditions; disagreements were found to be due to the theories’ insensitivity to influences from the particle phase and the frictional wall effect inside cyclone separators.

Packed bed reactors have many applications in different industries such as chemical, petrochemical, and refinery industries. In this work, the effects of some parameters such as the shape and size of particles, bed size, and bed length on the hydrodynamics of the packed beds containing three spherical, cylindrical, and cubic particles types are investigated using CFD. The effect of the combination of three particles types in a packed bed was also simulated. The simulation results show that flow channeling occurs in some parts of the bed which are not suitably covered by particles. It was also seen that flow channeling in the packed bed with cubic particles are more than those containing spherical and cylindrical particles. According to the CFD simulations, wake and vortex flows are created in all the beds, and the shape of particles affects these phenomena. The comparison of the pressure drop created in the packed beds indicates that the pressure drop in the packed beds having three particle types is lower than the packed beds containing only spherical, cylindrical, or cubic particles. Finally, the numerical results were compared with empirical correlations in the literature and showed good agreement.

In the present study, transesterification of soybean oil to Fatty Acid Methyl Ester (FAME) was carried out in the microreactor. The system performance was investigated in the presence of hexane as a cosolvent. Furthermore, the effect of number of micromixer’s inlets on the mixing was one of the objectives in this work. For the goals mentioned above, three different experiments were done with and without cosolvent in two and three inlet micromixers under optimum conditions. Both flow pattern observations and Gas Chromatgoraphy (GC) characterization of FAME samples demonstrated that cosolvent technique and micromixer application could significantly influence the FAME yield in biodiesel production.