Mixture Flow Research Articles

Thermo physical properties of diacetone alcohol with isomer butanols at different temperatures and correlation with the Jouyban–Acree model

ABSTRACT Excess molar volume, excess isentropic compressibility, deviation in viscosity and excess Gibbs free energy for activation of viscous flow for binary mixtures of 4-hydroxy-4-methyl-2-pentanone e (DAA) with 1-butanol (B1), 2-butanol(B2) and 2-methyl-2-propanol(B3) components selected compositions were determined from the measured values of densities (ρ), viscosities (), and speeds of sound (u) of pure components and their mixtures at from 303.15 K to 313.15 K. The results are analysed in terms of intermolecular interactions or hydrogen bonding or hetero-association interactions in the binary mixtures. Prigogine-Flory-Patterson (PFP) theory is applied to identify the predominant molecular interaction. Jouyban-Acree model results are discussed in terms of mean relative deviation (MRDs) and individual relative deviation (IRD) between calculated and experimental densities, speeds of sound and viscosities as an accuracy criterion

A Bingham Plastic Fluid Solver for Turbulent Flow of Dense Muddy Sediment Mixtures

We have developed and tested a numerical model for turbulence resolving simulations of dense mud–water mixtures in oscillatory bottom boundary layers, based on a low Stokes number formulation of the two-phase equations. The resulting non-Boussinesq equation for the fluid momentum is coupled to a transport equation for the mud volumetric concentration, giving rise to a volume-averaged fluid velocity that is non-solenoidal, and the model was implemented as a new compressible flow solver. An oscillating pressure gradient force was implemented in the correction step of the standard semi-implicit method for pressure linked equations (SIMPLE), for consistency with the treatment of other volume forces (e.g., gravity). The flow solver was further coupled to a new library for Bingham plastic materials, in order to model the rheological properties of dense mud mixtures using empirically determined concentration-dependent yield stress and viscosity. We present three direct numerical simulation tests to validate the new MudMixtureFoam solver against previous numerical solutions and experimental data. The first considered steady flow of Bingham plastic fluid with uniform concentration around a sphere, with Bingham numbers ranging from 1 to 100 and Reynolds numbers ranging from 0.1 to 100. The second considered the development of turbulence in oscillatory bottom boundary layer flow, and showed the formation of an intermittently turbulent layer with peak velocity perturbations exceeding 10 percent of the freestream flow velocity and occurring at a distance from the bottom comparable to the Stokes boundary layer thickness. The third considered the effects of density stratification due to resuspended sediment on turbulence in oscillatory bottom boundary layer flow with a bulk Richardson number of 1×10−4 and a Stokes–Reynolds number of 1000, and showed the formation of a lutocline between 20 and 40 Stokes boundary layer depths. In all cases, the new solver produced excellent agreement with the previous results.

UNIVERSAL HYDROGAS-DYNAMIC PATTERNS OF THE DRAINAGE ZONE OF OIL AND GAS WELLS

Large-scale experimental hydrogasodynamic studies of the flow of a two-phase gas-liquid mixture in a vertical pipeline were carried out. Based on the analysis of the results of these experimental studies, it was found that among the results obtained there are dependencies with theoretical bases by which theoretical hydrogasodynamic methods for studying multiphase flow in a vertical pipeline can be developed. The article provides a theoretical hydrogasodynamic study using dependencies describing a two-phase flow in a vertical pipeline of a round section, and it is confirmed by existing experiments. As a result of the gas-hydrodynamic study of pumping wells, in order to confirm the rational use of formation gas energy, a positive effect due to an increase in oil production rate and well process parameters, a relationship was established between well Q production rate, bottom-hole pressure of well P and production of formation gas V. Parameters can be modeled using three-term polynomials. During operation of wells in three modes (Qi, Vi or ∆Pi,Vi, where i = 1,2,3), processing of data obtained as a result of studies, indicators determined by existing research methods were obtained, and the technological mode ensuring layer-bylayer cooperation of the well system was selected.
 It is known that the motion of a two-phase flow of gas-liquid mixtures in a vertical pipe string is described on the basis of energy balance theory. The hydrogasodynamic characteristics of the drainage zone can be obtained in a real oil and gas well, as an experimental installation in the form of

Prediction Of Combustion Driven Oscillation In A Residential Ultra-Low NOx Gas Furnace Product Using A Positive Feedback Stability Model

Combustion oscillation is a very common phenomena in many unsteady or transient HVAC applications (e.g., start-up operation). Combustion driven oscillations can occur once the sound (thermo-acoustically driven) is reflected from the combustion chamber back into the mixture supply region (and propagate even further upstream). The reflected sound causes a fluctuation in inlet mixture composition or mixture flow. In either cases, the equivalence ratio is changed and consequently the amount of heat release changes. This phenomenon could easily trap the combustion process in a loop that can easily result in combustion oscillations with higher amplitude. It can also produce unwanted transient noise tones and can raise NOx emission levels. The current work is aimed at providing a simulation model for diagnosing and preventing combustion driven oscillation using a modified positive feedback loop. This feedback loop is developed using upstream/downstream impedances (obtained from low-order acoustic simulations), and a flame transfer function. The value-add of this study (model-based approach) is that it can help design engineers to reduce the number of test iterations and optimize the design.

Study of Water–Sand Inrush through a Vertical Karst Conduit Uncovered through Tunnel Excavation

The existence of karst compromises the safety of underground engineering, especially during tunnel excavations. Karst conduits are uncovered through tunnel excavations, which may lead to a water–sand inrush disaster. Taking a vertical karst conduit as an example, the process of water–sand inrush through a karst conduit could be viewed as being similar to the process whereby a water–sand mixture flows through the discharge opening of a storage bin. In this study, based on force analysis of a non-aqueous sand body above a karst conduit, the limiting diameter of the karst conduit under force equilibrium was obtained. Considering the effect of water on aqueous sand bodies, the criterion of water–sand inrush was established. We aimed to study water–sand migration and inrush through vertical karst conduits in order to obtain the distribution of the water pressure near a vertical karst conduit, and to explore the relationship between the conduit size, water pressure, and water–sand flow rate; therefore, a simulated testing system for analyzing water–sand inrush through a vertical karst conduit was developed. When the water pressure in the testing chamber was close to the critical head pressure of the water–sand inrush, the water–sand inrush exhibited a pattern of instability—migration—deposition—stability. When the water pressure in the testing chamber exceeded the critical head pressure, the water–sand flow increased first and then stabilized over time. With the increase in the set values of the water pressure and conduit size, the steady flow of the water–sand mixture increased gradually. When the karst conduit was opened suddenly, the actual water pressure in the testing chamber decreased significantly, due to the water–sand mixture flowing out of the testing chamber and the water supply lagging behind. With the stabilization of the water–sand flow, the actual water pressure gradually tended towards stability, but it was still lower than the initial set water pressure. When the karst conduit was opened, the values of the water pressure monitored by the pore pressure gauges all clearly decreased. With the stabilization of the water–sand flow, the water pressure gradually became stable. With the increase in the distance between the pore pressure sensor and the karst conduit, the water pressure values all increased gradually. These test results are significant for further studies of the formation mechanisms of water–sand inrush through vertical karst conduits.

Study on selected parameters of engine with the active combustion chamber

The present study was focused on the combustion engine with a variable compression ratio (VCR), namely the four-stroke air-cooled engine with the active combustion chamber (ACC). An indicated pressure, torque, power, and specific fuel consumption of that engine were investigated experimentally as a goal of the present study. Experiments were conducted using two versions of an engine. Two parameters particularly influencing the ACC engine performance including the maximum compression ratio CRmax and the indicator γfm determining the correct operation of the ACC system, were described. It was found that the ACC engine allowed avoiding detonation combustion without changing the amount and composition of the combustible mixture, and even without delaying the ignition advance angle. In addition, the possible range of control of the combustion process allowed the ACC engine to operate with different types of hydrocarbon fuels, for example, in the form of petrol with various alcohol admixtures . The very intense flow of the combustible mixture inside the cylinder of the ACC engine allowed describing the combustion in the ACC engine with zero-dimensional mathematical models with the dual Vibe function providing the proper characterization of the heat release process. The use of very high maximum compression ratios allows the ACC engine to operate to a certain extent as a Homogeneous Charge Compression Ignition (HCCI) engine with high lambda coefficients.

TECHNOLOGIES FOR THE DEPOSITS VOLUME ASSESSING USING REFERENCE LIQUIDS IN PIPELINES

The gas-liquid mixture flow along an oil and gas field pipeline is a complex process, the parameters of which, as a rule, are not determined along its length. Pressure and temperature of water-oil emulsion decrease along the pipeline length, pressure and temperature conditions of separation from oil both light components in the form of associated petroleum gas and heavy components – in the form of asphaltenes, resins, paraffins and mechanical impurities – change. Two techniques for deposit quantitative diagnostics in the pipeline are discussed in the article. Viscosity and velocity of injected reference fluid in the pipeline section complicated by deposits are considered as informative parameters when using pressure sensors and ultrasonic flowmeter.
 Technologies for the quantitative assessment of deposits in oilfield pipelines based on the control of the movement of a fluid with a reference property different from the property of the pipeline fluid are proposed. According to the first technology, the viscosity of the liquid is changed and the pressure difference at the beginning and at the end of the pipeline with deposits is fixed in time. According to the second technology, the value of the increased velocity of fluid movement in places where the pipeline is narrowed due to the presence of deposits is measured. The theoretical basis of the processes occurring with liquids in pipeline transport is substantiated. With an increase in the viscosity of the reference liquid, the degree of compression of the liquid increases and, as a result, the frequency of vibrations of the liquid molecules increases. With a decrease in the viscosity of the reference liquid, the reverse picture is observed.

Improving production and prediction of the flow regimes, pressure drop, and void fraction in the perforated horizontal wellbore

This study aimed to investigate how oil production could be improved by experimenting with different distribution methods across multiple profiles. The authors tested five different profiles that included uniform radial airflow (explained in profile 1) and variable radial airflow (explained in profiles 2, 3, 4 and 5) in a perforated horizontal wellbore. In addition, the study predicted the behavior of total pressure drop, superficial mixture velocity and void fraction encountered in different flow patterns (bubble, slug, stratum and stratum wave flow). Flow patterns were predicted using ANSYS Fluent R3 with a borehole length of 3 m and an ID of 0.0381 m. This was designed with 12 perforations opening vertically at the wellbore with a phase angle of 180 and a perforation density of 4 shots per foot to simulate the complex flow in a horizontal wellbore. In the perforated section, there was a fluctuation in the behavior of the parameters, while in the non-perforated section, the behavior remained constant. The behavior of the total pressure drop, the superficial velocity mixtures and the void fraction were also reasonably uniform in profile 1 in the perforated section.In contrast, they were irregular in the other profiles. In profiles 2, 3, 4 and 5, the behavior of the mixture superficial velocity and void fraction was inverse to the total pressure drop. Note that all theoretically calculated pressure drop modes increased as the Reynolds number of the mixture increased. The liquid and air product increased with increasing Reynolds number of mixture flow in the profiles. In contrast, in profile 1, lower production was obtained through all flow patterns due to the influence of the mixture pressure and the friction factor. The Vogels method was used to calculate maximum production from the horizontal wellbore. The convergence between experimental and numerical results was good during all cases (flow patterns), with some difference in the static pressure drop behaviuor occurring during flow patterns (bubble, dispersed bubble and slug flow).

Study on flow characteristics and interfacial interaction of two immiscible liquid phases on vertical wall

Water and silicone oil were used as an immiscible mixture, whose flow characteristics and liquid–liquid interfacial interaction on the vertical wall were analyzed by a combination of experiments and numerical simulations. The results indicated that the oil phase of the immiscible mixture flows on the wall as a liquid film, whereas the water phase flows on the oil film as droplets or rivulets. The immiscible mixture flow patterns can be divided into film-drop (FD), film-drop and rivulet (FD-RV), and rivulet (RV) flow according to the different flow behaviors of the water phase. A flow pattern map for the immiscible mixture of oil–water on the vertical wall was determined. In addition, the oil and water two phases influence the spreadability and fluidity of the liquid film, respectively. The water phaseflow can improve the oil film flow velocity, increase the oil–water interface shear stress, and change the oil film thickness.

A water cooled, high power, dielectric barrier discharge reactor for CO2 plasma dissociation and valorization studies

Aiming at the energy efficient use and valorization of carbon dioxide in the framework of decarbonization studies and hydrogen research, a novel dielectric barrier discharge (DBD) reactor has been designed, constructed and developed. This test rig with water cooled electrodes is capable of a plasma power tunable in a wide range from 20W to 2 kW per unit. The reactor was designed to be ready for catalysts and membrane integration aiming at a broad range plasma conditions and processes, including low to moderate high pressures (0.05–2 bar). In this paper, preliminary studies on the highly endothermic dissociation of CO2, into O2 and CO, in a pure, inert, and noble gas mixture flow are presented. These initial experiments were performed in a geometry with a 3 mm plasma gap in a chamber volume of 40cm3, where the process pressure was varied from few 200 mbar to 1 bar, using pure CO2, and diluted in N2. Initial results confirmed the well-known trade-off between conversion rate (up to 60%) and energy efficiency (up to 35%) into the dissociation products, as measured downstream of the reactor system. Improving conversion rate, energy efficiency and the trade-off curve can be further accomplished by tuning the plasma operating parameters (e.g. the gas flow and system geometry). It was found that the combination of a high-power, water-cooled plasma reactor, together with electronic and waveform diagnostic, optical emission and mass spectroscopies provides a convenient experimental framework for studies on the chemical storage of fast electric power transients and surges.

On the pressure drop calculation during the flow of two-phase non-azeotropic mixtures

• The effect of changes in the properties of the liquid and vapor phase during the flow of zeotropic mixture on the pressure drop. • The use of the equations of state of the liquid and vapor phases of a zeotropic mixture in the calculation of flow acceleration. • The approach has been developed for calculating the pressure gradient distribution and phase composition during the flow of a vapor-liquid zeotropic mixture. This article discusses the distinctive features of non-azeotropic vapor-liquid flows. It is shown that for the correct calculation of the pressure drop, the change in the thermophysical properties of the liquid and vapor phase along the flow must be taken into consideration. A calculation method that allows one to take the effect of a change in the composition of phases on the pressure drop and reasonably select a friction model for a two-phase flow has been proposed. In this method, the change in flow acceleration is calculated using the equations of state of the mixture for the liquid and vapor phases under phase equilibrium conditions. The method was verified. The calculation results are compared with experimental data from open sources for a non-azeotropic mixture of methane-ethane.

Особенности повышения надежности и эффективности газосепараторов погружных установок электроцентробежных насосов для добычи пластовой жидкости

In oil producing wells with high gas content, an increase in the efficiency of centrifugal pumps is achieved by equipping them with centrifugal gas separators, in which, before entering the pump intake, most of the free gas is taken from the pumped fluid and discharged into the annulus of the well. The efficiency of a centrifugal gas separator significantly depends on the size of the dispersity of the gas-liquid structure of the pumped fluid, on the diameters of gas bubbles, the water cut of the formation fluid, the presence of surfactants, and the pressure at the inlet and outlet of the pump. In the article, based on the analysis of the structural diagrams of the power part of gas separators of various manufacturers, the analysis of the gas-liquid mixture flow features in the separation chamber and the outlet device, recommendations are made for optimizing the separation chamber length and the gas separator head outlet design. Recommendations are proposed for changing the flow path to increase the efficiency of gas separation and reliability of operation. Explanations of the expediency of new design solutions based on empirical formulas and numerical simulations are proposed. It is shown what the information is most important and how it can be obtained in bench tests.

Patterns of air mixture movement in the operating area for the annular ejector of pneumatic transportation system

Purpose. To establish the regularities of two-phase flow of “gas-solid particles” in the operating area of an annular ejector where the following processes take place: air mixture ejecting, compressed air outflow from the ejector nozzle, air mixture flows mixing in the transport pipeline. In the work, the velocity distribution is also examined for dispersed phase and air phase of air mixture during its loading and accelerating in the transport pipeline of the pneumatic transport system. Methodology. The research is based on the fundamental approaches of mass point dynamics, aerodynamics, the theory of jet flows and iteration methods of numerical solution of equations. Findings. The mechanics of the air mixture flow under the ejection and aerodynamic force in the operating area of an annular ejector and at the beginning of transport pipeline is analyzed using the method of iterations. The impact of air mixture flow in the operating area of an annular ejector on energy performance of the pneumatic transport system is evaluated. Originality. The originality is that, for the first time, the regularities describing two-phase “gas–solid particles” flow at the loading area of the pneumatic transport system with an annular ejector have been obtained. This made it possible to characterize the velocity distribution of the dispersed and air phases of the air mixture during their loading and aerodynamic acceleration in the transport pipeline. Also, an innovative approach to the effectiveness of the use of pipeline pneumatic transport is the assessment of the energy indicators of the use of ejector-type pneumatic transport equipment depending on the rate of compressed air outflow from the ejector. Practical value. The implementation of the results in the modernization of existing and in the creation of new pneumatic transport systems with an annular ejector makes it possible to increase the efficiency of their use in the technological processes of moving dispersed materials at mining and metallurgical enterprises and in other areas of technology.

The research on the interfacial area transport equation in rectangular channels: Interfacial characteristics distribution and bubbles interaction mechanism

The interfacial area transport equation (IATE) is employed to describe the evolution of interfacial structure and evaluate the interfacial area concentration of two-phase flow. However, the interaction mechanisms among bubbles change in different rectangular channels, significantly impacting interfacial characteristics and source terms in IATE. In order to study the interface characteristics and mechanism of bubble interaction in rectangular channels with different gap sizes, an experimental study was conducted on the upward mixture flow of air and water in an adiabatic vertical channel under atmospheric pressure. Two channels with cross-sections of 4 × 66 mm and 8 × 66 mm were selected. The superficial velocities of water and air were 0.5–3 and 0–1.12 m/s, respectively, almost at the transitional region of bubbly to slug flow. Flat electrodes and the four-sensor probes measured the interfacial characteristics. This study analyzes the development of interface and mechanism of interaction among bubbles. The result shows that the evolution in the distribution of void fraction and interfacial area concentration significantly depends on the flow regime, flow rate, and cross-sectional geometric size of channels. Under the condition of a lower liquid flow rate, the gap size of the channel plays a vital role in the efficiency of bubble coalescence, influencing the mechanisms of the random collision and wake entrainment among bubbles. However, the interfacial parameter distribution under higher liquid rate conditions is dominated by turbulence intensity and flow regime, and the mechanisms of bubble interaction become identical. Finally, the mechanisms of interaction among bubbles (random collision and wake entrainment) are analyzed based on the development of interfacial characteristics. In a word, based on the conclusions specified in this research, the new models of source terms of ITAE in rectangular channels will be predictably established in the future.

Experimental and Computational Fluid Dynamics‐Based Simulation of Oil‐in‐Water Emulsion Flow through a Pipeline

AbstractDue to its high viscosity, heavy crude oil (HCO) is often transported through pipelines as concentrated oil‐in‐water emulsion. Here, emulsions were prepared with different concentrations of polyoxyethylene (5) sorbitan monooleate to study their flow characteristics through a horizontal pipeline. Laminar flow of HCO and an emulsion with 75 % (v/v) HCO and 25 % (v/v) water was simulated by using Ansys Fluent 2019 R3 to study the effect of temperature, volumetric flow rate, and surfactant concentration on pressure drop, dynamic viscosity, hydrodynamic entrance length, flow behavior index, consistency index, and pumping power requirement. Laminar flow of the emulsion was simulated by using a two‐phase mixture flow model considering the emulsion as a pseudo‐homogeneous mixture, while the flow of HCO was simulated as viscous laminar flow. Flow behavior index and consistency index were predicted from experimental viscosity data and used to predict pressure drop and, hence, the pumping power requirement.

Cost versus environment? Combined life cycle, techno‐economic, and circularity assessment of silicon‐ and perovskite‐based photovoltaic systems

Photovoltaics will play a key role in future energy systems, but their full potential may not be realized until their life cycles are optimized for circularity and overall sustainability. Methods that quantify flows of compound and minor element mixtures, rather than non-mixed elemental flows, are needed to prospectively analyze and predict inventory and performance for complex technology life cycles. This study utilizes process simulation to resolve the mass and energy balances needed to rigorously analyze these complexities in circular systems. Using physics-based prospective inventory data, we simultaneously assess the environmental and techno-economic performance of three photovoltaic life cycles and predict the effects of circularity on resource efficiency, carbon footprint, and levelized cost of electricity. One inventory dataset is generated per life cycle to ensure alignment between assessments and to identify trade-offs between environmental and techno-economic performance with respect to circularity, so linking circularity and sustainability. The linked material and energy resource and techno-economic models allow for the impacts of carbon taxation and the moderating effects of circularity to be explored. In addition to the clear environmental benefits of increased circularity, we find that it could dampen the cost impact of taxation. While confirming that perovskite-based modules, single junction or in tandem with silicon, clearly outperform the silicon market standard both techno-economically and environmentally, we show that maximum circularity does not automatically deliver the most sustainable outcome. The approach enables assessment of the combined impacts of specific technological, commercial, and policy choices made by different actors along the photovoltaic value chain. This article met the requirements for a gold–gold JIE data openness badge described at http://jie.click/badges.

Falling film evaporation in a partially heated parallel plate channel: Elliptic numerical analysis with an excess moisture condensation model

A fully coupled elliptic numerical method is used to conduct a detailed numerical analysis of laminar water falling film evaporation with a co-current laminar gas vapour mixture flow inside a partially heated vertical parallel plate channel. In order to obtain a fully coupled implicit solution, a complete set of elliptic two-phase two-dimensional governing equations is solved. The liquid-gas interface is obtained over a non-orthogonal structured moving mesh (grid) during the solution process. An excess moisture condensation model is proposed as a novel numerical method to address supersaturation in the system. Comparisons with the previous studies are made to verify the accuracy and capability of the present numerical model. The effects of the liquid and mixture Reynolds numbers variation on the hydrodynamic and thermal characteristics of the evaporation process inside the partially heated channel are investigated. Thermal and solutal buoyancy effects are seen in the form of recirculating flow in the gas phase.

An Approximate Analytical Model of a Jet Flow with Mach Reflection and Pulsed Energy Supply at the Main Shock

The supersonic flow of a reactive gas mixture with Mach reflection of oblique shocks and pulsed energy supply at the Mach stem is considered within the framework of the Chapman–Jouguet theory. An approximate analytical model is proposed that quickly determines the shape and size of the shock-wave structure as well as the flow parameters in various flow regions. As an example of the application of the proposed analytical model, the “first barrel” of a highly overexpanded jet flow of an air-methane mixture with a high supersonic velocity, is studied. Flows of hydrogen–air and hydrogen–oxygen mixtures were also considered for comparison with preceding numerical results. The height of the triple point of the Mach reflection is determined in the presence of a change in the chemical composition of the mixture and an isobaric pulsed energy supply at the main shock.

Analysis on phase distribution and flow field morphology in double side blown gas-liquid mixture flows with high temperature and high density melt

In view of the gas-liquid two-phase flow process in the oxygen-enriched side-blown molten pool, the phase distribution and manifold evolution in the side-blown furnace under different working conditions are studied. Based on the hydrodynamics characteristics in the side-blown furnace, a multiphase interface mechanism model of copper oxygen-enriched side-blown bath melting was established. The results show that the existence of slag baffle makes the velocity distribution range of melting mixing zone wider, the mixing range of melt wider, the mixing effect better, and the role of melting zone strengthened. The average speed of case MY in the melting zone is the highest, nearly 5.2% higher than that of case EY, and 16.7% higher than that of case EN. Compared with the average turbulent kinetic energy in the melting zone, case MY has a significant advantage of 2.635 m2/s2, which is increased by 47%, 34%, and 14% respectively compared with case EN, case EY, and case MN.

Model fluids substituting fresh UHPC mixtures flow behaviour

Carboxymethylcellulose (CMC) and ultrasound gel (USG) seem to be suitable clear model fluids to substitute real ultra-high-performance concretes (UHPCs), enabling experimental monitoring of events occurring within these mixtures at similar flow behaviour. USG is eligible for UHPC mixtures with significant yield stress. CMC having a suitable concentration is better for UHPCs exhibiting indistinct yield stress. The rheological behaviour of real UHPC mixtures as well as substituting model fluids was measured using a non-standard system consisting of a vessel stirred by an anchor or a screw agitator. In addition, a standard rotational rheometer system with concentric cylinder geometry was used for optimization of the above-mentioned method of measurement and also for measuring the rheological parameters of the substituting model fluids. This article deals with the methodology for measuring the rheological properties of these substances and presents the results of the measurements using flow curves and rheological models.