Concentration Of Solid Particles Research Articles

Direct Numerical Simulation of Fully Developed Turbulent Gas–Particle Flow in a Duct

Direct numerical simulation of a fully developed turbulent flow of a viscous compressible fluid containing spherical solid particles in a channel is carried out. The formation of regions with an increased concentration of solid particles in a fully developed turbulent flow in a channel with solid walls is considered. The fluid flow is simulated with unsteady three-dimensional Navier – Stokes equations. The discrete trajectory approach is applied to simulate the motion of particles. The distributions of the mean and fluctuating characteristics of the fluid flow and distribution of the concentration of the dispersed phase in the channel are discussed. The formation of regions with an increased concentration of particles is associated with the instantaneous distribution of vorticity in the near-wall region of the channel. The results of numerical simulation are in qualitative and quantitative agreement with the available data of physical and computational experiments.

Solution of One-dimensional weak shock wave problem in a Non-ideal dusty Medium: An analytical approach

The main emphasis of the present study is to construct an analytical solution subjected to weak shock-jump conditions (R-H conditions) for the propagation of a one-dimensional adiabatic flow of non-planar weak shock waves in a two-phase gas-particle medium (mixture of non-ideal gas and small solid spherical dusty particles). By taking into account the methodology used by Murata, the influence of mass concentration of solid particles and van der Walls parameter of non-idealness has been reported explicitly on the exact solution of flow parameters and total energy of the flow field behind the shock front. Also, an investigation has made for the estimation of radius of shock front and results has been illustrated via figures. It has been observed the radius of shock front (damage radius) attenuates faster with time on increasing the impact of mass concentration of solid particles and volumetric parameter in the mixture.

Increasing the Time between Failures of Electric Submersible Pumps for Oil Production with High Content of Mechanical Impurities

The main principles of hydroabrasive wear of parts of the pumping stages of well’s electric submersible pumps are considered in this article. The concentration, grain-size distribution and shape of solid particles have the greatest impact on the abrasion ability of particles of mechanical impurities interacting with the parts of pumping equipment. The implementation of filters is the most effective and affordable way to protect borehole electric submersible pumps from hydroabrasive wear. Filters reduce the concentration and decrease the average grain-size of mechanical impurities going through the pumping stages. The authors propose variants of constructive and schematic solutions of self-cleaning slot filters, providing an increase in the operating time of electric centrifugal pump units during production of well fluid with a high content of mechanical impurities. The operating principle of the proposed filters is described. The results of calculations of deformation of tubing string during the increase in pressure at the oil wellhead are presented, confirming the possibility of restoring the permeability of spring filter elements without lifting the pump unit to the surface.

Влияние первой волны пандемии COVID-19 на экосистему Европы

The results of analytical studies are presented, which show that restrictive measures for reduction of SARS-CoV-2 propagation speed and the incidence of the COVID-19 pandemic on the territory of Western Europe and the Russian Federation have led to a significant reduction of anthropogenic load on the natural environment and a considerable improvement of environmental conditions for the main types of contaminants. At the same time there is a dramatic growth of total ozone in the troposphere during the period of restrictions almost for all studied territories. It is revealed that after finishing the restrictive measures the level of air contamination reached its initial point: by September in Western Europe and by October in the European part of Russia. The calculations demonstrated that poor air quality aggravates the consequences of COVID-19, and a significant contribution is made by the PM2.5 concentration of fine solid particles, which can penetrate deeper into the human lungs and exacerbate the course of respiratory diseases. Keywords: COVID-19, ecology, tropospheric conditions, satellite information, morbidity level and air quality

Влияние первой волны пандемии COVID-19 на экосистему Европы

Hydrometeorological Research and Forecasting, 2021, no. 4 (382), pp. 112-133. The results of analytical studies are presented, which show that restrictive measures for reduction of SARS-CoV-2 propagation speed and the incidence of the COVID-19 pandemic on the territory of Western Europe and the Russian Federation have led to a significant reduction of anthropogenic load on the natural environment and a considerable improvement of environmental conditions for the main types of contaminants. At the same time there is a dramatic growth of total ozone in the troposphere during the period of restrictions almost for all studied territories. It is revealed that after finishing the restrictive measures the level of air contamination reached its initial point: by September in Western Europe and by October in the European part of Russia. The calculations demonstrated that poor air quality aggravates the consequences of COVID-19, and a significant contribution is made by the PM2.5 concentration of fine solid particles, which can penetrate deeper into the human lungs and exacerbate the course of respiratory diseases. Keywords: COVID-19, ecology, tropospheric conditions, satellite information, morbidity level and air quality

The assessment of environmental parameters of roadside territories on the example of the Orenburg Region cities

Environmental management and planning of the urban environment, the inclusion of natural landscapes in it is becoming increasingly important today. The paper discusses the latest researches in printed Russian and foreign publications that study the impact of roads and roadside landscaping on the quality of the urban environment and the life of citizens. The dependence of the influence of urban greening on temperature, runoff, heat flows, carbon dioxide, the content of solid particles and gas pollution is shown. The analysis of studies in which environmental recommendations are given to reduce these impacts is carried out. Roads as a dangerous object of urbanized environment should be surrounded by a buffer green zone. The importance of studying the location of the main streets and identifying landscaping around them in urban centers is indicated. The paper contains an assessment of the environmental parameters of roadside zones, depending on the level of their landscaping and the remoteness of residential development from the roadway, in large cities of the Orenburg Region. General and specific recommendations on environmental optimization of spaces have been compiled, allowing to reduce the environmental burden on the roadside environment through effective planning of green infrastructure, which will provide a basis for improving the health of the population and their quality of life.

Analysis of Complex Solid-Gas Flow under the Influence of Gravity through Inclined Channel and Comparison with Real-Time Dual-Sensor System

Gas-solid flow is used in the chemical industry, food industry, pharmaceuticals, vehicles, and power generation. The calculation of flow has aroused great interest in contemporary industry. In recent decades, researchers have been seeking to build an effective system to monitor and calculate gas-solid flow. Attempts have been extended from computational modeling to the creation of flow pattern visualization methods and mass flow (MFR) quantification. MFR is usually studied by volume flow concentration (VFC) and velocity distribution of solid particles. A non-invasive device is used for testing MFR, in which electronic and mechanical sensors are used to balance the shortcomings related to each other. This study investigates the simulation of flow patterns to demonstrate the behavior of solid particles as they pass through the channel. The particles are allowed to slide longitudinally in the insulated tending channel. This slippage is due to the influence of natural gravity. Electronic sensor components are used to measure the velocity distribution and concentration of volumetric flow. The load cell is used as an auxiliary sensor for measuring MFR. In addition, ANSYS fluent is used to analyze streaming queries. The experimental results are related to evaluating the accuracy and relative error of the data collected from various sensors under different conditions. However, the simulation results can help explain the movement of the gas-solid mixture and can understand the cause of pipeline blockage during the slow movement of solid particles.

Study on Different Parameters of the Self-Excited Oscillation Nozzle for Cavitation Effect under Multiphase Mixed Transport Conditions

The pollution problems of water resources have affected the ecology of the Earth, especially the ecological environment of the oceans. In order to find a cheaper and cleaner organic wastewater treatment method and explore the effect of geometrical parameters and external parameters of self-excited oscillation on cavitation performance, apply it in engineering stably and efficiently, this study took the cavitation effect of self-excited oscillating cavitation jet nozzle as the research target and simulated the geometrical parameters and external parameters of the nozzle. The primary and secondary relationship of the effect of all parameters on cavitation performance was summarized by analyzing the correlation and partial correlation of each parameter. Subsequently, principal component analysis (PCA) was conducted to build a mathematical model of self-excited oscillating cavitation jet nozzle suitable for multiphase transport. As revealed from the results, the contribution rate of parameters to vapor volume fraction followed the order of CLD > d1 > Cd21 > CDd2 > Pin. The ratio of outlet diameter to inlet diameter (Cd21) of the self-excited oscillating cavitation jet nozzle significantly impacted the volume fraction of cavitation vapor (VOF) due to the change of particle diameter, while the influence of other design parameters on VOF was not significant with the change of particle diameter. The larger the content of solid particles, the less the VOF would be impacted by the design parameters. Under the solid particle content of 10% and the particle diameter of 0.2 mm, an independent working point was obtained. In addition, after experimental verification, it was found that the slope of experimental fitting was basically the identical to the corresponding coefficient of parameters in the model. This model and the self-excited nozzle with good cavitation performance provide a theoretical basis for solving the problem of water pollution.

Exponential shock wave in perfectly conducting self-gravitating rotational axi-symmetric dusty gas with magnetic field, radiative and conductive heat fluxes

In the present paper, we study the exponential shock propagation in a self-gravitating rotational axisymmetric perfectly conducting mixture of van der Waal gas and solid particles with magnetic field either axial or azimuthal and radiative and conductive heat fluxes. In our model, the solid particles are distributed continuously in the mixture and are chemically inert, and the equilibrium conditions for flow are preserved in the entire region of flow field behind shock wave. In a thick gray gas model case, the radiation is assumed to be of diffusion type. The Fourier's heat conduction law is used to express the heat conduction. The effects of the problem parameters variations are discussed. It is shown that the density of micro size solid particles to the gas initial density ratio or the gravitational parameter or the rotational parameter or the gas adiabatic index has effects to enhance the shock wave strength. Also, it is derived that an increase in the nonidealness of the gas, Alfvén Mach number, and the mass concentration of solid particles in the mixture have decaying effects on the strength of shock wave. It is shown that the shock wave is stronger when magnetic field is axial and weaker for azimuthal magnetic field.

Foam stability properties of eco-friendly three-phase foam system reinforced by polydopamine@KH560/ (octyl)-trimethoxysilane modified basalt

To achieve high stability of foam extinguishing system, basalt(BAS) was first modified and added to form a three-phase foam system in this study. Firstly, the polydopamine(PDA) was coated on the surface of BAS. After that, the γ-(2,3-epoxypropoxy)propytrimethoxysilane(KH560) and (Octyl)-trimethoxysilane (OTMOS) were further grafted on the BAS surface to improve the dispersion and hydrophobicity. the modified results were verified by FT-IR, TG, and XRD. Secondly, factors including the surfactant type, concentration, temperature, and the mass concentration of solid particles were also studied. The results indicated that the foam performance of sodium dodecyl sulfate(SDS) was better than other surfactants. Within a certain range, the foam performance enhanced with the increasing stirring speed, time, and solid mass concentration. Moreover, the stability of the three-phase foam fire extinguishing agent added with modified BAS was significantly improved compared with the two-phase foam, and the 50% drainage time reached 28.03 mins, which was more than 4 times that of the two-phase foam. Hence, the optimized basalt eco-friendly three-phase foam is expected to play an effective application in the fire extinguishing and prevention of huge fires. • Basalt(BAS) was modified by dopamine coating and in-situ grafting. • The method employed an environmentally friendly surfactant as a two-phase system. • The influence of process parameters on foam properties was discussed. • The obtained BAS has high performance in foam stabilization.

Study on the erosion wear in pipe fittings

In the pipeline system for slurry, local erosion wear failure has become the main damage mechanism of pipe in the fracturing operations of oil-gas engineering. Computational Fluid Dynamics simulation is performed to determine the evolutionary process of erosion wear in tubing connector, which is the resistance of pipeline system, and a new way to predict the pipeline longevity is provided. Based on the Euler equation, solid particle concentration in the slurry and interphase momentum exchange are included in the liquid flow equations due to the influence of dense particle on slurry (slurry is a two-phase flow), and the particle trajectory were calculated in the Lagrange frame by analyzing the forces from the interaction of liquid and particle and particles impact. With the erosion damage model, the erosion rate/depth in the connector was calculated to reconstruct the mesh model of shoulder with 5 tori. Torus 1 is closest to axis while torus 5 is on the outmost wall of the connector. During the erosion event, greatest erosion and hence surface deformation occurs on tori 1 and 2, and this affects the surrounding flow and particle movement. After 10 hours of erosion, there was a dramatic drop in the maximum erosion rate, which illustrated a conservative prediction for pipeline service life if the initial erosion rate was used. An erosion experimental setup was also performed to identify the weight loss and erosion characteristic of the inner surface with erosion time of 55 hours. It was observed that the erosion simulations provided relative errors within 18% for erosion length and weight loss compared to the experimental values and a closed form equation for the erosion rate was proposed to predict the erosion life of tubing connector

Quality of veiled olive oil: Role of turbidity components

This study investigated the effects of water and content of solid particles, taken together as well as separately, on stability of veiled olive oil. The following oil samples were obtained through four different separation treatments: veiled, filtered, ‘solid-only’, and ‘water-only’. Changes in chemical, microbial, and sensory characteristics were evaluated during storage (240 days). A significant effect of hydrolysis was shown in veiled and ‘water only’ oils; in ‘solid-only’ oils, a slow increase of phenols was observed. A notable microbial activity, with resulting formation of volatile metabolites and sensory defects, was observed in veiled samples. Filtered oils underwent less significant changes.

Experimental Investigation on the DPF High-Temperature Filtration Performance under Different Particle Loadings and Particle Deposition Distributions

Based on DPF filtration and regeneration bench, the solid particle emission and high-temperature filtration characteristics of different carbon black particle loadings and particle deposition distributions are studied. The aerosol generator (PAlAS RGB 1000) is used to introduce carbon black particles into the inlet of a DPF, and the NanoMet3 particle meter is used to measure the solid particle concentration at the inlet and outlet of a DPF to obtain the filtration characteristics. Previous studies found that without inlet carbon black particles, there was an obvious solid particle emission peak at the outlet of the deposited DPF during the heating, and the concentration increased by 1–2 orders of magnitude. In this paper, the high-temperature filtration characteristics under steady-state temperature conditions are studied. It is found that a DPF can reduce the range of inlet fluctuating particles, and with the increase of temperature, the proportion of large solid particles in the outlet particles increases, and the size distribution range decreases. Particle loading has positive and negative effects on the DPF filtration, and the DPF has the optimal particle loading, which makes the comprehensive filtration efficiency improve the highest. The deposition transition section can make the deposition particles in the DPF uniform, but the filtration efficiency is reduced.

Large Eddy Simulation of Particle Transport and Deposition Over Multiple 2D Square Obstacles in a Turbulent Boundary Layer

AbstractPredicting solid particle transport in the lowest parts of the atmosphere is a major issue for man‐made obstacles in semi‐arid regions. Here, we investigate the effects on solid particle saltation, of square obstacles on the ground with different spacings. The aerodynamic field is determined by large eddy simulations coupled with an immersed boundary method for the obstacles. Solid particles are tracked by a Lagrangian approach. Take‐off and rebound models are introduced for the interaction of particles with the wall. Without particles, fluid velocity profiles are first compared with experiments (Simoens et al., 2007, https://doi.org/10.1016/j.atmosenv.2007.08.013) showing good agreement. Special focus is put on the recirculation zone that plays an important role in solid particle entrapment.Particle concentration fields are presented. Accumulation zones are studied regarding the different obstacle spacings as an extension of the aerodynamic scheme by Oke (1988, https://doi.org/10.1016/0378-7788(88)90026-6) to solid particle transport. A deposition peak appears before the first obstacle. When the spacing between the two obstacles is large enough, some particles are trapped within the recirculation and a second deposition peak arises. The streamwise evolution of the horizontal saltation flux shows that the lowest flux downstream of the obstacles is obtained for the highest separation. The deposition rate or the streamwise saltation flux are estimated globally as a function of obstacle spacing. These results illustrate how the numerical tool developed here can be used for assessing air quality in terms of solid particle concentration.

Evaluation of the Erosion Characteristics for a Marine Pump Using 3D RANS Simulations

In the present study, an erosion analysis of an industrial pump’s casing and impeller blades has been performed computationally. Effects of various critical parameters, i.e., the concentration and size of solid particles, exit pressure head, and cavitation on the erosion rate density of the casing and blade have been investigated. Commercial codes CFX, ICEM-CFD, and ANSYS Turbogrid are employed to solve the model, mesh generation for the casing, and mesh generation of the impeller, respectively. The Eulerian-Eulerian method is employed to model the pump domain’s flow to solve the two phases (water and solid particles) and the interaction between the phases. Published experimental data was utilized to validate the employed computational model. Later, a parametric study was conducted to evaluate the effects of the parameters mentioned above on the erosion characteristics of the pump’s casing and impeller’s blade. The results show that the concentration of the solid particles significantly affects the pump’s erosion characteristics, followed by the particle size and distribution of the particle size. On the other hand, the exit pressure head and cavitation do not affect the erosion rates considerably but significantly influence the regions of high erosion rate densities.

Surface modification of carbon steel by electrodeposit composite coating for improving erosion-corrosion resistance: a review

This paper included an explanation of one of the methods of protection from corrosion, as it dealt with the use of electroplating technology by using solid ceramic particles embedded in chromium on carbon steel as a base material as an effective way to increase the service life of fluid-carrying tubes, considering that they are exposed to a joint effect of chemical and physical action. The formation of composite coatings on carbon steel and the factors affecting the success of these coatings in addition to a group of studies that dealt with these factors and their impact on increasing the resistance to conditions surrounding the metal represented by resistance to chemical corrosion in the presence of erosion (such as the concentration of solid particles in the paint solution, the temperature of the paint solution, the effect of The current density on the quality of the coatings and the effect of the thermal treatment on the coatings). The current density, the concentration of solid particles and the temperature have the greatest influence in determining the efficiency of the composite coatings.

The effect of solid particle size and concentrations on internal flow and external characteristics of the dense fine particles solid–liquid two-phase centrifugal pump under low flow condition

In the energy conversion device and fluid transport equipment, the solid–liquid two-phase centrifugal pump occupies a large proportion, but the transport mechanism of dense fine particles has not been studied in detail. In this work, the solid–liquid two-phase flow in a centrifugal pump was numerically simulated by the mixture model. Two-phase performance tests with different particle concentrations and particle sizes at a low flow rate (0.6Qd) were conducted, and dimensionless analysis on the effect of particle concentrations and particle sizes on head and efficiency was conducted. The results show that the increase in particle size and particle concentration can increase the influence coefficient of head and efficiency and the influence of the two parameters on efficiency is greater than that on the head on the whole. The increase in particle size and concentration will lead to more uneven distribution of the solid volume fraction in the pump. The transport of dense fine particles absorbs a large amount of energy, which leads to the relative decrease in the kinetic energy of the liquid phase and inhibits the generation of the vortex in the impeller passage.

Comparison of micro-explosive fragmentation regimes and characteristics of two- and three-component droplets on a heated substrate

The paper presents experimental research findings for the regimes (puffing and micro-explosion) and integral characteristics of the fragmentation of two- and three-component droplets on a heated substrate, as illustrated by emulsions and slurries. The main droplet components were water with a fluorophore Rhodamine B (9 vol%), tetradecane (91 vol%) and bituminous coal particles measuring 5–110 µm (0.05–0.27 wt%). The conditions for the occurrence of micro-explosion were determined. The integral characteristics of the processes under study were compared: delay times, minimum sufficient temperatures, duration of breakup and threshold temperature differences. Specific aspects of water microdroplet formation in two- and three-component droplets at the heating stage were recorded and described. The effect of the mass concentration of solid particles in the slurry droplet on the temporal characteristics of explosive fragmentation was shown. The conditions for efficient fragmentation of the droplets under study were established, based on the dimensionless integral criteria. Approximations were derived for the mathematical description of the plotted curves.

Analytical solution for unsteady adiabatic and isothermal flows behind the shock wave in a rotational axisymmetric mixture of perfect gas and small solid particles

Abstract The approximate analytical solutions are obtained for adiabatic and isothermal flows behind a cylindrical shock wave in a dusty gas. A mixture of perfect gas and micro size small inert solid particles is taken as the dusty gas. The inert solid particles are distributed continuously in the mixture. It is considered that the equilibrium flow conditions are maintained. The flow variables are expanded in power series to obtain the solution of the problem. The analytical solutions are obtained for the first order approximation in both the adiabatic and isothermal cases. Also, the system of ordinary differential equations for second order approximations to the solution is obtained. The influence of an increase in the ratio of the density of the inert solid particles to the initial density of the perfect gas, the rotational parameter and the mass concentration of inert solid particles in the mixture are discussed on the flow variables for first approximation. Our first approximation to the solution corresponds to the Taylor’s solution for the creation of a blast wave by a strong explosion. A comparison is also made between the solutions for isothermal and adiabatic flows. It is investigated that the density and pressure near the line of symmetry in the case of isothermal flow become zero and hence a vacuum is formed at the axis of symmetry when the flow is isothermal. Also, it is found that an increase in the value of rotational parameter or the mass concentration of solid particles in the mixture has a decaying effect on shock wave. The present work may be used to verify the correctness of the solution obtained by self-similarity and numerical methods.

Application of response surface methodology for the optimization of viscosity of foam fracturing fluids for the unconventional reservoir

Maintaining the optimum viscosity of foam required to create the effective fracture permeability and placing the proppant inside the fracture are difficult because of its poor thermal stability. The objective of this study is to optimize the viscosity of foam by using the Response Surface Methodology (RSM) technique. The Box-Behnken design matrix was selected based on the feasibility, efficiency and simplicity of response surface methodology, which contains 17 number of experiments. Statistical analysis of the model was performed by Analysis of variance (ANOVA), which helps to confirm the robustness of the tested model. The diagnosis of the model was reported with internally studentized residual plots, which proves that the data is authentic with less error value, and the model is significant. The desirability function approach is utilized to analyze the optimized viscosity, followed with a confirmation test, which assists in validating the predicted optimal viscosity results. The input parameters, such as solid particles concentration and foam quality, were set in a range and temperature was set to be at maximizing condition, so that corresponding response, i.e., viscosity was optimized. The optimized viscosity of the foam fracturing fluids systems is in between 36.74 and 74.61 cP at 500 s−1 shear rate. The abovementioned methods and its analysis for the estimation of the optimal viscosity at a high shear rate are very significant and consequently acceptable for the design and development of foam fracturing fluid at the field conditions of unconventional reservoirs. This method is expected to apply for effective designing of foam for fracking of unconventional reservoirs without undergoing rigorous field trials for selecting the correct foam composition.