Suspended Sediment Particles Research Articles

In-Stream Laser Diffraction for Measuring Suspended Sediment Concentration and Particle Size Distribution in Rivers: Insights from Field Campaigns

This study evaluates the laser in situ scattering and transmissometry (LISST) instrument LISST-SL2, a laser diffraction instrument for suspended sediment sampling in rivers, with concurrent physical measurements of suspended sediment concentration (SSC) and particle size distribution (PSD) as well as velocity measurements by an acoustic Doppler current profiler (ADCP). We collected 136 LISST-SL2 samples along with 61 physical samples for SSC measurement, of which 24 physical samples included PSD measurement during 2018–2020 from 11 sites in Washington state and Virginia. An effective density is required to convert the measured volumetric SSC by the LISST-SL2 into a reported mass SSC, and by default the LISST-SL2 assumes a value of 2.65 g/mL. From our data set, we computed effective densities (mass SSC/volumetric SSC) that ranged from 0.5 to 5.4 g/mL, with a best-fit value of 2.05 g/mL. Additionally, the LISST-SL2 was not able to measure the finest sediment sizes in suspension, which affects the resulting PSD. Therefore, we propose some adjustments of the LISST-SL2 data with a supporting physical sample to account for these effective density and PSD issues. When doing so, we were able to reduce the root-mean square relative error (RMSRE) to 18% from 117% for SSC, and to 26% from 78% for PSD. LISST-SL2 velocities were generally higher than ADCP velocities with a 21% RMSRE. Our results and guidance will allow for more accurate sampling by the LISST-SL2, which has potential for studying spatial and temporal variation of suspended sediment characteristics in rivers.

Widespread occurrence of quaternary alkylammonium disinfectants in soils of Hesse, Germany.

Quaternary alkylammonium compounds (QAACs) are cationic organic compounds with amphiphilic properties that are widely used as surfactants and disinfectants in industry, households and agriculture. Several studies suggest that QAACs co-select for antibiotic resistant microorganisms and thus may contribute to the spread of antibiotic resistance in the environment. Data on QAAC occurrence in soil are scarce and limited to soils that are prone to direct exposure to QAACs. Therefore, we conducted a comprehensive study on the occurrence of QAACs in soils of Hesse, a federal state in Germany, covering an area of 21,115 km2. Sixty-five soil samples that comprised different land uses (arable, grassland, forest, vineyard) and area types (rural, agglomeration) were analysed for concentrations of alkyltrimethylammonium (ATMACs, with alkyl chain lengths C8-C16), benzylalkyldimethylammonium (BACs, C8-C18) and dialkyldimethylammonium compounds (DADMACs, C8-C18) via HPLC-MS/MS after ultrasonic-assisted extraction with acidified acetonitrile. QAACs were detected in 97 % of the soil samples irrespective of land use and area type. The most abundant QAAC homologues were DADMACs > BACs > ATMACs. The highest total QAAC concentrations were detected in alluvial soils influenced by the deposition of suspended particles during flood events, with DADMAC-C16 and -C18 as the dominant homologues. The high abundance of long-chain DADMACs suggests that legacy pollution and accumulation govern QAAC concentrations in soils. The presence of QAACs in forest soils points to a potential input via atmospheric deposition. Our work highlights the widespread occurrence of QAACs in soils of Hesse and the need for more research on their entry paths and fate in the soil ecosystem.

Current velocity field in section of Sai Gon river during operation of flood control structures

The largest economic center in Vietnam - Ho Chi Minh City, is facing increasingly serious riverbank erosion, one of the main reasons being the flow. Therefore, in this study, the flow velocity field on the Saigon River section is accurately analyzed in different time intervals with the help of MIKE 11 and MIKE 21 models. The simulation results show that The number of flow velocities in the middle of the river is 3-4 times greater than that of the two banks. However, between high tide and low tide, the flow on both sides of the river is faster than the main flow, especially in the upper part of the winding banks, such as the section from Ben Nghe sluice to Tan Thuan, sewer and river section from An Loi Dong Ward police station to Thu Thiem Bridge 2. The velocity value on the studied river section, in most cases, exceeds the allowable value of the non-erosion velocity of the bed material particles. , riverbanks, as well as suspended sediment particles. Therefore, the erosion process on both sides of the river will occur regularly and continuously, so urgent measures are needed to protect the riverbank. During the operation of the anti-flood sluice, the flow velocity will decrease slightly before sluices also appear as whirlpools. The flow velocity on the Saigon River has a complex distribution and changes from time to time depending on the flood discharge from Dau Tieng Lake and the tidal currents of the East Sea.

Promotive Effects of Siltfence on Deposition of Suspended Particles: Evaluations of Diffusion Suppression of Radionuclides in Rectangular Open Channel via Numerical Simulations

A siltfence is installed to prevent the spread of suspended sediments generated by engineering construction works in rivers and on the coast. Thus, the siltfence is regarded to be a tool to prevent radioactive materials adsorbed on suspended sediments from diffusing into the sea in ports of nuclear power plants during nuclear accidents. However, the prevention effects of the siltfence as sediment control structures have not yet been fully evaluated. Therefore, in this paper, we simulate the behaviors of suspended sediment particles using a coupled simulation scheme composed of water flow and deformation of the siltfence in a rectangular open channel under uniform steady flow, and evaluate the promotive effects of the installed siltfence on suspended sediment deposition. The results demonstrate that the installation of the siltfence significantly promotes deposition, especially of particles with low settling velocities. However, it should be noted that the opposite case is also possible, i.e., the siltfence promotes the diffusion of suspended sediments under particular conditions. These results suggest that a careful installation strategy is necessary. The present simulation scheme is useful in assessing the prevention effects of siltfences prior to their installation.

Effect of mixed magnetic field on physical properties of atmospheric suspended fine particles

In recent years, the fine particles suspended in the atmosphere, especially the particle size less than 10 μm, have caused very adverse effects on the climate environment and human health. However, the current research on the causes of air pollution mainly focuses on human activities and weather conditions. Considering the weak magnetism and chargeability of atmospheric fine particles, this study proposed a new view that space electromagnetic radiation may affect the physical properties of fine particles. We first analyzed the dynamic characteristics of magnetic micro-particle in the electromagnetic environment, and built a simulation model in the COMSOL simulation software. Finally, based on the theoretical analysis and simulation results, we built an experimental verification system to evaluate the effects of electromagnetic radiation on the physical properties of micro-particle, and carried out a 30-day control experiment. The experimental results showed that the physical properties such as particle size distribution, mass concentration, and morphology of suspended fine particles in the atmosphere under electromagnetic radiation are significantly different from those under non-electromagnetic radiation environment. It can be inferred that the aggregation, fusion, and deposition of suspended particles in the atmosphere are closely related to the complex electromagnetic environment in space.

Morphological Evolution Characteristics of River Cross-Sections in the Lower Weihe River and Their Response to Streamflow and Sediment Changes

River cross-section morphology and water and sediment conditions are deeply connected. In recent years, the lower Wei River has experienced regular flooding and drastic changes in river channel shape, causing significant harm to the economy and development of the lower reaches. This research investigated the morphological evolution features based on annual extensive cross-section data and water and sediment data from the hydrological stations of Xianyang, Lintong, and Huaxian in the lower Weihe River from 2006 to 2018 of river cross-sections and the reaction to water and sediment variations. The findings indicated that the lower Wei River’s cross-sectional alterations between 2006 and 2018 exhibited a trend of “flushing at both ends and siltation in the middle” while continuing to exhibit “non-flood flushing and flood siltation” features. The incoming sediment coefficient in the lower Weihe River declined dramatically, whereas the median diameter of suspended sediment particles grew significantly at the Lintong station. The average elevation of the river channel was highly synchronized with the change in the coming sediment coefficient, and the impact of big floods dramatically influenced the shape of the river cross-section. Human activities such as river management have directly affected the morphology of the river cross-section at Lintong station and caused a significant increase in the median diameter of suspended sediment particles, resulting in siltation in the Lintong river. The study’s findings can serve as a theoretical foundation for water and sediment regulation and river training in the lower Weihe River, reducing flooding damage.

Spatial Variations in Microfiber Transport in a Transnational River Basin

Five countries share the catchment of the Tisza River (Central Europe). In most households electricity and water are available, and by washing synthetic clothes they can produce a large number of microfibers. However, in many sub-catchments of the river, the wastewater treatment is insufficient; therefore, microplastics (MP), especially plastic microfiber emissions into rivers, represent a problem. Our goal was to analyze the suspended sediment and microfiber transport at the low stage, making repeated (2021 and 2022) measurements in the Tisza River (946 km) at 26 sites across three countries. Water sampling was performed by pumping 1 m3 of water through sieves (90–200 µm). The mean MP transport in 2021 was 19 ± 13.6 items/m3, but it increased by 17% in 2022 (22.4 ± 14.8 items/m3). The most polluted sections were the Upper Tisza (Ukraine, Hungary) and the Lower Tisza (Serbia), where wastewater treatment is not satisfactory, whereas the Middle Tisza (Hungary) was less polluted. The tributaries increased the sediment and MP budget of the main river. Microfibers dominate (84–97%) the suspended MP transport, and thus it can be determined that they originated from wastewater. The MP transport was influenced by the availability of wastewater treatment plants, dams, tributaries, and mobilization of bottom sediments. At the low stage, no connection was found between the suspended sediment and MP particle transport.

Stream nitrogen uptake associated with suspended sediments: A microcosm study

Despite significant advances in our understanding of nitrogen (N) removal pathways along river networks, the role of water column processes remains largely understudied. This knowledge gap not only limits our capacity to determine N transport and retention in mid-to-large rivers but also hampers our understanding of N removal processes in smaller streams during stormflow conditions, in which significant increases in suspended sediment concentrations (SSC) typically occur. High SSC in the water column can provide abundant substrate for microbial growth and water column N uptake. However, storms of different size mobilize different quantities of sediment of varying properties and sizes, which can ultimately modulate water column N uptake rates in the stream during stormflows. To assess water column N uptake associated with suspended sediment particles of different sources and sizes, we quantified assimilatory and dissimilatory N uptake rates in a set of microcosms representing a gradient of sediment properties (organic matter, N content, and microbial activity) and surface area (fine vs. coarse size) availability. Water column assimilatory uptake (Used) ranged from 12.7 to 187.8 µg N [g sediment]−1 d−1 across all sediment sources and size fractions, and was higher on average than denitrification rates (DNsed) in agricultural and stream bank sediments but not in streambed sediments (mean DNsed = 240.9 ± 99 µg·N [g sediment]−1·d−1). Sediment-bound C in suspended sediment varied among sediment sources and was directly related to Used rates, but not to DNsed rates, which were less predictable and more variable. Overall, our results showed a positive nonlinear relationship between water column N uptake and SSC, while indicating that water column N uptake may scale differently to SSC depending on sediment source, and to a lesser degree, particle size. Because low, moderate, and large storms can mobilize different quantities of sediment in the watershed of different sources and sizes, it is likely that storm size will ultimately modulate the contribution of water column uptake during storm events to whole-reach N retention.

Fractional derivative modeling for sediment suspension in ice-covered channels.

Characterizing the anomalous diffusion behavior of sediment transport is a key factor in calculating sediment concentration. This study attempts to seek an equation that captures the nonlocal movement feature of the transport of an ensemble of sediment particles on ice-covered channels with a steady uniform flow field. Given that the fractional advection-dispersion equation with a noninteger order on the space term is nonlocal and able to describe the long-distance transport, a mathematical model with the Caputo fractional derivative is proposed to estimate the vertical diffusion of suspended sediment particles in the ice-covered channel. Results show that the fractional derivative model has a good predictive ability to the suspended sediment concentration as compared to the measurements. Especially in regions close to the undersurface of the ice cover, the proposed model matches better with experiments than the existing analytical model. Sensitivity analyses indicate that the strength of the turbulent diffusion effect dominates the uniformity of the sediment concentration profile. Besides, the sediment concentration is more sensitive to the variation of the boundary roughness than to the change of the sediment settling velocity. It should be noted that the sediment concentration reduces with the decrease of the order of the fractional derivative, which differs from the findings in previous studies.

Estimation of Fractal Dimension of Suspended Sediments from Two Mexican Rivers

Sampling programs for suspended sediment were carried out in the Usumacinta River and its tributary Grijalva River in Mexico during the years 2016 and 2017. Suspended sediment samples collected during these sampling programs were analyzed in the laboratory using a Rotating Annular Flume (RAF) fitted with a Particle Tracking Velocimetry (PTV) to obtain the 2D images of the suspended sediment particles as they were undergoing floc reconstruction, and subsequently using a glass settling column fitted with inline digital holography set up to obtain 3D holograms of the fully flocculated sediment particles. From these high-resolution hologram images, the fractal dimension of the flocculated sediment particles was obtained using the classical box-counting method and an improved Triangular box-counting method. The estimated fractal dimension of flocculated sediment, which is a measure of floc compactness and structure that control the settling velocity of flocculated sediment was used to validate two empirical models to estimate the fractal dimension in terms of the floc sizes of suspended sediments of these two rivers. It is shown in this study that the floc characteristic can be analyzed in laboratory experiments after floc reconstruction with the use of an RAF and it offers a viable alternative to the costly in-situ sampling that is often carried out in ocean research. The digital holography method employed in this research offers an efficient methodology to obtain the floc fractal dimension. Regarding the innovative aspects and new contribution to science, we can say that we have developed a laboratory protocol to test river waters to establish floc properties such as fractal dimensions of flocs in this research which will help to test river waters on a routine basis with manageable costs. We can also say that we have developed models to predict the relationship between floc fractal dimension and floc size, which did not exist before.

Generalized non-equilibrium suspended sediment transport model with hindered settling effect for open channel flows

The present paper formulates a generalized model for non-equilibrium suspended sediment transport through an open channel turbulent flow that contains all the existing models in literature as special cases. The two-dimensional (2D) unsteady model for suspended concentration distribution contains the effect of hindered settling and the bottom boundary condition considers deposition velocity together with equilibrium bottom concentration. OpenFOAM, an open-source Finite Volume (FV) method based framework, has been used for the numerical approximation of the model. The proposed model addresses the non-linearity in the governing equation as well as the non-linearity in boundary conditions. Picard iteration approach has been utilized to ensure the convergence of the numerical solution. With different physical parameters and conditions, concentration profiles of suspended sediment particles have been analysed theoretically and graphically. It greatly extends the domain of the numerical solutions for determining sediment distribution in suspension through an open channel turbulent flow in a non-equilibrium state.

Linear stability analysis of sediment-laden planar turbulent jets in shallow waters

When a river debouches into a shallow receiving basin, it behaves as a sediment-laden shallow jet which plays a key role in the subsequent sediment transport and morphological evolution at the river mouth. A linear stability analysis that directly incorporates the effect of the presence of suspended sediment on the hydrodynamic instability of shallow jets was performed in this study. The sediment effect was accounted for using a two-way coupling. The onset of the instability was found to be generally insensitive to the addition of moderate quantities of suspended sediment particles. However, an eigenfunction analysis indicated that the nonlinear development of the instabilities may indeed be affected by the presence of sediment. The results of this study have important implications for estuarine and deltaic geomorphology, and can inform delta restoration projects such as artificial diversion to achieve maximum land building potential.

Effects of physical disturbance of sediment on the cycling of mercury in coastal regions

Mercury (Hg) is a global pollutant of health concern due to formation and bioaccumulation of methylmercury (MeHg) during its biogeochemical cycle. Coastal areas are important regions in the biogeochemical cycling of Hg (Liu et al., 2017), where often-occurring natural and anthropogenic perturbations affect Hg transport and transformation and the associated health risk from Hg. The rapidly growing mariculture associated with the rising global demand for food may have a profound effect on coastal Hg cycling, due to the environmental alterations (e.g., resuspension and sedimentation) caused by maricultural activities (e.g., bottom sowing and harvesting). Through simulating the effect of water scouring, a common harvesting method, this study investigated Hg migration and distribution in particulate and dissolved phases in Laizhou Bay of Bohai Sea, China, where mariculture exists extensively. Particulate total and methyl Hg (PTHg and PMeHg) in water (expressed as ng/L) increased sharply due to the resuspension of sediment, but decreased rapidly after a one-off scouring event. When normalized by particle mass, PTHg and PMeHg (ng/g) in suspended sediment particles were significantly higher than that in the initial sediment, suggesting a higher distribution coefficient and higher affinity to bind Hg in the suspended particles. This may be due to the smaller particle sizes, and higher contents of organic matter and Fe/Mn of suspended sediments compared to the initial sediment. While the concentrations of dissolved THg (DTHg) in water column showed minimum changes or decreased, dissolved MeHg (DMeHg) concentrations increased sharply after the perturbation, due to the possible release of MeHg from porewater and potential Hg methylation during the event. These results provide fundamental information needed for ecological and health risk assessment of Hg in mariculture, and highlights the increased mobility and bioaccumulation of MeHg during anthropogenic perturbations in these areas.

Inferring Suspended Sediment Carbon Content and Particle Size at High Frequency From the Optical Response of a Submerged Spectrometer

AbstractReal time monitoring of suspended sediment (SS) carbon content and particle size information is essential to understand SS transport mechanisms and processes. However, limited in situ methods are available, and manual and unattended sampling makes high frequency observation challenging. Based on evidence that optical measurements of SS concentration are dependent on particle size and composition, we hypothesize that SS carbon content and mean particle size can simultaneously be inferred from the absorbance data measured with a submerged spectrometer at high frequency. With the aim to predict both parameters, we investigate if global calibrations can be obtained and used instead of site‐dependent local calibrations. To test this, we created a laboratory data set using a tank setup, and an in situ field data set. Sediment samples varying in composition were collected and used in a tank setup to obtain global (all sites grouped together) calibrations between absorbance, particle size and carbon content. Two sites were instrumented to collect in situ field data, to generate local (site‐specific) calibrations and to validate the global calibrations obtained in the laboratory. A procedure to account for the effect of SS concentration when using the global calibration to predict is also presented. Our findings indicate that global calibrations can accurately predict from in situ absorbance readings, with a median absolute error of 17.3 μm, versus 10.5 μm for a local calibration. Local calibrations are indispensable to reliably predict carbon content, with a median absolute error of 1.3%.

The interplay of suspended sediment concentration, particle size and fluid velocity on the rapid deposition of suspended iron oxide particles in PVC drinking water pipes

The inner walls of drinking water pipes are often expected to be clean and controlled surfaces to assure safe water access to the public. However, these surfaces are typically contaminated with particulate materials and biofilms that eventually degrade water quality. While water utilities place significant efforts in identifying and flushing material deposits from compromised pipes, the development of effective preventive strategies is still limited by the lack of knowledge about material accumulation processes. The aim of this paper is to examine the interplay between suspended sediment concentration, particle size and fluid velocity and the attachment of suspended iron oxide particles in PVC drinking water pipes. For that purpose, a series of short experiments were completed, whereby water amended with a known concentration of selected and stable iron oxide particles was introduced in a full-scale pipe loop laboratory over a short period of time and both turbidity and suspended sediment concentration (SSC) were measured at the inlet and outlet of the pipe loop. Results showed that a selected fraction of the injected particles with sizes above a specific threshold in the range of 4.6 to 6.8 µm had not reached the downstream section of the pipe loop, but instead remained attached to the pipe walls. In addition, exponential decay of the SSC was observed to occur along the pipes and to cause most of the sediments to accumulate in the upstream section of the pipe loop. The research improved our understanding of the physical processes of particulate material accumulation in DWDSs, and it will help water utilities forecast and monitor material accumulation and discolouration potential.

Sediment Remediation Using Activated Carbon: Effects of Sorbent Particle Size and Resuspension on Sequestration of Metals and Organic Contaminants.

Thin‐layer capping using activated carbon has been described as a cost‐effective in situ sediment remediation method for organic contaminants. We compared the capping efficiency of powdered activated carbon (PAC) against granular activated carbon (GAC) using contaminated sediment from Oskarshamn harbor, Sweden. The effects of resuspension on contaminant retention and cap integrity were also studied. Intact sediment cores were collected from the outer harbor and brought to the laboratory. Three thin‐layer caps, consisting of PAC or GAC mixed with clay or clay only, were added to the sediment surface. Resuspension was created using a motor‐driven paddle to simulate propeller wash from ship traffic. Passive samplers were placed in the sediment and in the water column to measure the sediment‐to‐water release of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and metals. Our results show that a thin‐layer cap with PAC reduced sediment‐to‐water fluxes of PCBs by 57% under static conditions and 91% under resuspension. Thin‐layer capping with GAC was less effective than PAC but reduced fluxes of high–molecular weight PAHs. Thin‐layer capping with activated carbon was less effective at retaining metals, except for Cd, the release of which was significantly reduced by PAC. Resuspension generally decreased water concentrations of dissolved cationic metals, perhaps because of sorption to suspended sediment particles. Sediment resuspension in treatments without capping increased fluxes of PCBs with log octanol–water partitioning coefficient (K OW) > 7 and PAHs with log K OW of 5–6, but resuspension reduced PCB and PAH fluxes through the PAC thin‐layer cap. Overall, PAC performed better than GAC, but adverse effects on the benthic community and transport of PAC to nontarget areas are drawbacks that favor the use of GAC. Environ Toxicol Chem 2022;41:1096–1110. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Influence of Natural Processes and Bottom Trawling in the Nepheloid Layer Structure Off Vancouver Island (British Columbia, Canada, NE Pacific)

Continental margins are transitional areas between the land and the deep ocean where large amounts of particulate matter are supplied, transported, and ultimately deposited in the deep sea. High-energy hydrodynamic processes such as storms, ocean currents, or internal waves and tides, as well as bottom trawling activities contribute to the resuspension and remobilization of these particles. These mechanisms favor their transference from the continental shelf to the continental slope and maintain high concentrations of particulate matter in the water column forming nepheloid layers. The temporal evolution of the hydrographic and nepheloid structure in the upper slope off Vancouver Island (British Columbia, Canada, NE Pacific) was assessed by analyzing 4 months (from mid-August to late-November 2018) of sensor data from Ocean Networks Canada (ONC) NEPTUNE cabled seafloor observatory. The distribution of particulate matter during the study period illustrated a well-defined turbidity structure consisting of surface nepheloid layers (SNLs) at <100 m depth associated to primary and secondary productivity, intermediate nepheloid layers (INLs) between 150 and 300 m depth at the shelf-break and upper slope domain, and bottom nepheloid layers (BNLs) developed at >400 m depth. Moderate storm events occurred during fall when the more intense INLs were recorded at shelf-break depths. However, not all the INLs recorded during this period occurred in coincidence with these storms, indicating that these INL detachments were modulated by a different sediment resuspension mechanism. Analyses of fishing vessel activity during the study period revealed that trawlers operated over the same depth range as these INLs. Our results suggest that, in combination with the regional currents, the presence of continuous fishing along the continental slope off Vancouver Island contributes to the advection of suspended sediment particles, playing a major role in their transfer as nepheloid layers.

Spatio-temporal deposition profile of an experimentally produced turbidity current with a continuous suspension supply

A turbidity current is a turbulent, particle-laden gravity current that is driven by density differences resulting from the presence of suspended sediment particles. The current travels downslope, bearing a large amount of sediment over a great distance, and forms fluvial and submarine bedforms. Knowledge of the spatio-temporal deposition profile of turbidity-deposited sediment is important for a better understanding of sediment transport by turbidity currents. In the current study, the depositional process of experimentally produced quasi-steady turbidity currents in an inclined flume was investigated using an electrical-resistance-based depositmeter. It was found that the amount of sediment deposited along the flume bottom increases linearly with time at a specific rate, and decreases exponentially in the downstream direction. Inspired by this observation, the mass conservation law was modified for the suspension layer and a simple theoretical model was proposed involving two parameters, the initial sedimentation rate and the decay constant. The proposed model reproduces the observed data from the flume experiment with high accuracy, and is consistent with the sediment transport distance of a natural example, the Bengal Fan. It was concluded that the two parameters that govern the sedimentation process are the key to estimating the deposition profile of fluvial systems.

Monitoring on triboelectric nanogenerator and deep learning method

As the basic hydrological parameters, the concentration and type of suspended sediment particles greatly influence the aquatic ecological environment and the water conservancy infrastructure. However, because of the various composition and changing concentration, challenges still remain in low-cost and real-time sediment monitoring. Herein, we report a potential method to realize real-time monitoring of sediment particles parameters by introducing a particles-laden droplet-driven triboelectric nanogenerator (PLDD-TENG) combined with deep learning method. The mechanism of PLDD-TENG was proved to be induced by the liquid-PTFE electrification and particles-electrode electrostatic induction. The output signals of PLDD-TENG were measured under different particles types and mass fractions. The results indicated that the output signals were sensitive to the particles type and mass fraction. A convolutional neural network (CNN) deep learning model was adopted to identify the particles parameters based on the output signals of PLDD-TENG and high identifying accuracy was achieved. Meanwhile, this model can identify particles types in the mixed solution. An intelligent system was finally developed to realize visualization of real-time monitoring for sediment particles. These findings are crucial in both fundamental understanding and application prospect of triboelectric effect in two-phase flow.

Refinement of arrangement of purifying elements of integrated air treatment device for gas transmission systems and power generation based on computational fluid dynamics

Gas pumping units with gas turbine units (GTU) are widely used in gas transmission systems. In recent decades, GTUs are increasingly used in power generation at thermal power plants. The efficiency and reliability of a gas turbine plant largely depend on the quality of air preparation. Integrated air cleaning devices (KVOU) as part of the air intake duct of the GTU have stages of coarse and fine air purification and rather large dimensions. The possibility of using a battery cyclonefilter with cleaning elements, in which both stages of cleaning are combined, in the design of the KVOU is considered. Numerical studies of the movement of a two-phase flow in a multicyclone, which is a model of the first 2 rows of a serial multicyclone, have been carried out. The first two rows of the serial multicyclone TsB-16 of the Biysk boiler plant, consisting of 16 cyclone elements 245 mm in diameter with a semi-coil gas supply, were taken as the initial geometric model. The geometric model was built using the Gambit preprocessor: a two-dimensional 2D model and a finite element mesh based on square elements were built. The finite element mesh of the numerical model generated in the Gambit program was exported to the solver of the ANSYS Fluent software package. Using the methods of computational hydrodynamics, the nature of the movement of a dusty flow in a battery cyclone with a corridor arrangement of cyclone elements has been investigated, their most effective placement has been determined, which provides the maximum inertial capture of suspended particles, in accordance with which a localization scheme for semi-coil entrances to treatment elements has been determined. In numerical studies, the aerodynamic characteristics of the dispersed flow in the multicyclone body are obtained. In accordance with the results of numerical studies, the efficiency of inertial sedimentation of suspended particles from the flow in the first row of elements was 36%, in the second row — 99%.