Cyclone Device Research Articles

Creation and research of numerical models of cyclones with inclined and horizontal inlets

The article considers the challenges of using cyclone devices for cleaning gas emissions from solid fuel combustion in power engineering and industry. With the increasing energy consumption and generation, including the use of coal, the requirements for the efficiency of cleaning emissions from small solid particles of classes PM10 and PM2.5 are also rising. One of the key tasks is to maintain high cleaning efficiency while minimizing energy costs, which is also important for reducing the environmental impact of generation and industrial production. The article considers the design features of currently used cyclones, as well as existing approaches to their classification. The main focus is on modern areas of research related to numerical modeling based on CFD (Computational fluid dynamics) aimed at optimizing the design of separators. It is shown that most studies are carried out for cyclone operating conditions in production cycles, rather than in emission cleaning systems that operate at low suspended matter loads. Using the example of creating numerical models of cyclones with inclined and horizontal inlet pipes (CN-11, SK-CN-34), the article discusses certain features of geometry creation in the SpaceClaim Direct Modeler (SCDM) environment, which ensure the correctness of grid generation and calculations in the future. The results of numerical modeling carried out using the ANSYS Fluent software are presented. The turbulence model (RANS, Reynolds Averaged Navier – Stokes), methods for closing the Navier – Stokes equations (k-ε model with near-wall functions), and methods for calculating the dispersed part of the flow (Euler – Lagrange, DPM) are selected based on the conditions relevant to the systems for cleaning emissions from coal generation. The results indicate that, with the same pressure drop, the efficiency of settling suspended matter with a concentration of 100 mg/m3 or less in an apparatus with an inlet angle of 11° to the horizontal can be higher than that of a cyclone with a horizontal inlet.

Separation of multicomponent gas mixtures

In the production of granular organo-mineral fertilizers using the fluidization technique by dehydrating heterogeneous liquids, as an energy-efficient technology, there is a need to purify the spent coolant containing solid particles, dust and a significant amount of water vapor. Solid particles up to 20 microns in size are effectively captured in cyclone devices. To further capture water vapor and fine solid particles, a scrubber is used with an additional circulation circuit involving an additional bone of water, which, upon reaching a concentration of more than 20%, is discharged back to the granulation stage. This leads to an increase in energy consumption for production in general. Condensation of vapors in a dispersion containing 5-7% (w/w) moisture in the form of water vapor at the second stage of purification will increase the level of environmental safety in production. To select an innovative method of separation of multicomponent gas dispersions accompanied by a change in the aggregate state and a rational design of the apparatus, a review of scientific articles and developments such as systematization of existing methods was carried out. Such an approach makes it possible to choose the optimal solution for the separation of gas-dust and gas-liquid flows in the conditions of the existence of a large number of types of equipment design and the level of their innovation. In addition to the rational design of the devices, great attention was also paid to the issues of energy efficiency, resource saving and ensuring the state of environmental safety at production facilities in the conducted research. Based on the results of the analysis, it is proposed to use a scheme of consecutively installed cyclones CN-11 and SK‑CN-33. It is proposed to use the ЦН-11 cyclone for the preliminary capture of highly dispersed dust, and the SK-CN‑33 for condensation and capture of water vapor and solids not caught in the previous cyclone particles.

Comparison of experimental, empirical, and CFD pressure losses of lab-scale sampling cyclones

Significant efforts remain to be undertaken to achieve efficient separation of particulate matter. Devices widely used for this purpose are cyclone separators. This study investigates the pressure loss phenomena and flow structures within cyclone devices, aiming to elaborate and optimize their performance. Traditional cyclone models: (i) Muschelknautz, (ii) Stairmand, and (iii) PM1 Sharp Cut, are evaluated alongside the innovative vortex limiter cyclone (VL) to distinguish their advantages and limitations. The focus is on describing the relation between pressure loss and flow characteristics of the different cyclones with the same design separation diameter of 1μm. Empirical pressure loss correlations analyze how pressure losses vary within different cyclone devices. It was proven that predictions depend on cyclone size and operational parameters. Computational Fluid Dynamics (CFD) simulations further elucidate pressure loss mechanisms, highlighting the complexities inherent in modeling cyclonic behavior accurately. In conclusion, this study contributes to advancing the understanding of cyclone performance by elucidating the intricate interplay between pressure loss phenomena and flow structures. Such insights hold profound indications for optimizing cyclone separator design and operation in diverse industrial applications.

Author’s innovative technical solutions in the field of ecology and life safety for use in fuel-burning and ash-collecting devices

The study reviews and recommends fundamentally new technical solutions in the field of ecology and safety in the technosphere, confirmed by patents for inventions and utility models developed by scientists and graduate students of the Department of Technosphere Safety of the Far Eastern State Transport University. Innovative developments that are of practical interest and deserve attention include installations for preparing water-oil emulsions for combustion, energy-saving devices for environmentally friendly combustion of liquid fuels, rational designs of low-toxic gas and oil burners, as well as effective filter-cyclone and group cyclone devices for purification of flue gases from coal and fuel oil boiler and furnace units.

Evaluation of air pollutants emitted from wastewater treatment processes in Egypt

AbstractDespite the importance of wastewater treatment plants (WWTPs) to decontaminate wastewater, and consequently relieving the global freshwater reserves of industrial and domestic pollution, their effect on the air quality of the surrounding areas is often overlooked. The main aim of this work was thus to evaluate the nature and levels of common air pollutants released from different operating processes of a major WWTP in Egypt (Abu‐Rawash WWTP). Concentrations of gaseous pollutants (CO, NO2, SO2, NH3, H2S, total volatile organic compounds) and particulate matter (PM2.5, PM10, and total suspended particulates) at each of the wastewater treatment operation processes within the premises were measured from September to December 2019. The intercorrelations between all pollutants were examined by principal component analysis using Minitab 17 statistical software. The results showed that the highest emission rates of gaseous pollutants were derived from the sludge thickening and dewatering process, and from the sedimentation tanks, whereas the highest levels of particulate matter were detected at the sludge handling facilities and cyclone devices. However, the recorded levels were generally lower than the maximum threshold limits set by the Egyptian Environment Laws (Law 4 of 1994 for the Protection of the Environment amended by Law 9/2009, and Law 105/2015) and the European Commission air quality guideline. This study emphasizes that the environmental impacts resulting from the direct air emissions of gases and particulates should be closely monitored if wastewater facilities are located in the vicinity of residential areas.

Correcting Coal Miner Respirator Total Inward Leakage Values for Respiratory Tract Deposition.

The great majority of workplace respirator efficacy studies have measured total inward leakage (TIL) for particulate contaminants. One of the first such studies, designated the Harris study, was conducted in the early 1970s in US underground coal mines. As in other particle-based studies, inside-the-facepiece dust sampling was continuously conducted across the inhalation and exhalation phases of the breathing cycle, although unlike in other studies, respirable dust cyclones were used in air sampling. Because exhaled air was partially depleted of dust particles due to deposition in the respiratory tract, the measured time-averaged dust concentration inside the facepiece underestimated the time-averaged dust concentration inspired into the facepiece. In turn, the reported TIL values underestimated the true TIL values experienced, which is to say, overestimated respirator efficacy. This paper describes a method to correct the Harris study's reported TIL values for respiratory tract deposition while accounting for particle size-selective sampling by the cyclone devices. Given the estimated coal mine particle size distribution outside the respirator, it is shown that the reported TIL values should be increased by the multiplicative factor 1.69. This paper also discusses the assigned protection factor (APF) of five for the quartermask respirator class and shows that 4/5 quartermasks in the Harris study did not meet the criterion for complying with this APF value when using the corrected TIL values.

Study of the structure of gas flow іn a cyclone wіth іntermedіate dust removal

The works in which designs of the dust collectors, which are often used in the industry, are analyzed. It is shown that the efficiency of dust collectors largely depends on the structure of the gas flow in the apparatus. Based on the analysis of the current cyclone devices, a picture of the separation process is obtained, and the factors that negatively affect the operation of dust collectors are identified. It is established that forecasting the work of dust collecting devices in certain conditions is most effective to perform methods of numerical modeling and simulation of the separation process, which are widely used for the research of devices of this type. Using the methods of numerical simulation, the study of the cyclone with intermediate dust removal was carried out. In this cyclone, the change in the radius of the apparatus of the tangential, radial, and axial velocity components is investigated. In the course of the research, it is established that in the separation space the tangential component of velocity increases from 18–20 m/s in the upper part of the device to 22–25 m/s in the area of the lower end of the exhaust pipe, the radial component of velocity takes values from 0 to 2 m/s, and the axial component of the speed has a maximum value of 10–15 m/s. In the conical part of the apparatus the tangential component of velocity decreases from 27 m/s in the upper planes of the conical part of the apparatus to 10 m / s near the dust unloading pipe, the radial component of speed has centripetal character, the axial component of speed decreases as the gas flow to the dust unloading pipe decreases. It has been established that in the cylindrical part of the apparatus about 60 % of the gas flow volume is transferred from the downstream to the upstream by a secondary vortex, and in the conical part, about 40 % of the gas volume is transferred from the downstream to the upstream. It is shown that large values of the tangential component of velocity in the separation zone contribute to the ingress of dust particles into the annular space behind the dust unloading holes, and small values of the tangential component of velocity, axial and radial in the annular space behind the dust unloading holes has a positive effect on the operation of the dust collector.

True shape modeling of bio-particulate matter flow in an aero-cyclone separator using CFD–DEM simulation

The multi-phase flow of air and bio-particulate matter exists in many biological and environmental systems such as aerodynamic separating devices, fluidized bed combustion, and feed processing machinery. Integration of the computational fluid dynamics (CFD) and discrete element method (DEM) codes was performed to study bio-particle loading ratios' effect on the cyclone device performance. Every individual particle's behavior was captured by a DEM model using Newton’s equations of motion, in which CFD modeled the continuum airflow for every computational cell scale through the Navier–Stokes equation. According to the high turbulence and chaotic behavior of the continuum airflow inside the cyclone separator, Reynolds stress turbulence model (RSM) was used. The particles used for testing and modeling were conducted on two mixture types of real-heterogeneous particulate matter, namely jojoba seeds and jojoba leaves, without any fly ash. The particles were geometrically modeled using their actual dimensions and shapes, considered the first head start research approach in the cyclonic separation and purification field. The influence of the interacting particle–particle and particle–boundary forces was taken into consideration. The numerical simulation results successfully predicted the cyclone performance at the designed conditions, which showed the best experimental data trend. These data are useful in future studies to modify the cyclone design and optimize bio-systems' operating conditions for separating the macroscopic particulate matter.

Aerodynamics, convective heat exchange and energy efficiency of cyclone devices with large relative length

The main purpose of the work was to optimize the design of the cyclone devices with large relative length. Studies of aerodynamics and convective heat exchange in cyclone devices have been performed to determine their optimal parameters. Two methods for determining the aerodynamic and thermal efficiency of cyclone chambers are proposed. The analysis according to the proposed methods was carried out and the optimal geometrical and regime parameters of cyclone chambers were determined, ensuring minimal energy costs and an increase in efficiency.

Aerodynamics and Stability of the Flow in Relatively Long Cyclone Chambers

The article presents and analyzes the results of an experimental study of the aerodynamics of the flow in the working volume of cyclone chambers of a large relative length, significantly exceeding the length of the chambers that were used in the previous studies. Air supply to the chamber swirler was carried out tangentially from diametrically opposite sides by two inlet channels. The air discharge from the working volume of the chamber was made from the opposite end of the chamber through a round axisymmetric hole. The values of the area of the inlet channels and the diameter of the outlet were varied with replaceable incrustations and clamps. The experiments were performed with the use of laser Doppler anemometry. As a result, previously unknown features of flow formation in the working volume of relatively long cyclone chambers have been determined. The main characteristic values of the working volume flow have determined as well. In particular, the determining influence of the flow core characteristics on its structure in relatively long cyclone chambers has been discovered. The calculated ratios have been chosen to determine these values depending on the geometrical characteristics of the chamber under study. The boundary of the near-wall flow region, in which favorable conditions for the flow instability are created, is determined. Numerical simulation of the flow in the ANSYS Fluent software has been performed. Based on its results, a comparison of the results of numerical simulation, calculated dependencies and experimental data is presented. A comparison of the results demonstrated a completely satisfactory coincidence. Data obtained in the process of research and calculated ratios can be used in engineering practice and are of an interest from the point of view of further study of aerodynamics in a highly swirled flow of cyclone devices in order of to improving the methods of their thermal and aerodynamic calculations.

A novel flip-flop based error free, area efficient and low power pipeline architecture for finite impulse recursive system

An error free, area efficient and low power pipeline architecture for finite impulse recursive signal processing system on chip (SOC) is proposed. The pipeline stage is implemented for the FIR filter which forms the signal conditioning block of the SOC in 60 and 90 nm technology. The design, implementation and testing is performed using Altera Quartus 9.1, cyclone device family for 60 and 90 nm technology. The pipelining is designed with 3 and 5 stages. The combinational block consists of processing elements like array multiplier and ripple carry adder. The registers of the pipelining is designed using normal D flip-flop, Autogated and Razor flip-flop. The pipelining architecture is further extended towards shared component architecture. The proposed shared component architecture reduces the critical path, number of components by which area is reduced and power consumption. The proposed design reduces the error with fewer timing penalty. The results are compared with existing methods and the efficiency of proposed method is improved. The proposed flip flop is compared with the existing flip-flop and found that the static power consumption is reduced by 8% and dynamic power consumption by 56%. The proposed pipelined shared component architecture reduces the power consumption by 10% for static power and 75% for dynamic power. From the machine cycles execution analysis it is found that the proposed design saves clock cycles when an error occurs. When area is considered the proposed architecture contains less number of multipliers.

Microbial activity balance in size fractionated suspended growth biomass from full-scale sidestream combined nitritation-anammox reactors

The purpose of this study was to determine the abundance, distribution and activity of aerobic ammonia-oxidizing bacteria (AOB) and anammox in size fractionated aggregates from full-scale suspended growth combined nitritation-anammox sidestream reactors. Plants with or without a cyclone device were also studied to assess a purported enrichment of anammox granules. Specific aerobic ammonium oxidation rates (p=0.01) and specific oxygen uptake rates (p=0.02) were significantly greater in flocs than in granules. AOB abundance measured using quantitative FISH was significantly higher in flocs than in granules (p=0.01). Conversely, anammox abundance was significantly greater in granules (p=0.03). The average ratio of anammox/AOB in systems employing hydrocyclone separation devices was 2.4, significantly higher (p=0.02) than the average ratio (0.5) in a system without a hydrocyclone. Our results demonstrate substantial functional and population-level segregation between floccular and granular fractions, and provide a key corroboration that cyclone separation devices can increase anammox levels in such systems.

Gas Cleaning System with a Pre-Unloading Flow

The analysis of the causes and mechanisms reduce the efficiency of processes separation in cyclone devices, the results of field surveys of industrial cyclone. It offers an alternative solution to clean the flue gases from the boiler KE-10/14.

CONVECTIVE HEAT TRANSFER IN CYCLONE DEVICE WITH EXTERNAL GAS RECIRCULATION

The article considers the convective heat transfer on the surface of a hollow cylinder or several billets in a cyclone device with the new principle of external gas recirculation. According to this principle, transport of coolant from the lateral surface of the chamber, where the temperature is the highest, in the axial region is being fulfilled due to the pressure drop between the wall and axial areas of cyclonic flow. Dependency analysis of average and local heat transfer coefficients from operational and geometrical parameters has been performed; the generalized similarity equations for the calculation of the latter have been suggested. It is demonstrated that in case of download of a cyclone chamber with several billets, the use of the considered scheme of the external recirculation due to the specific characteristics of aerodynamics practically does not lead to noticeable changes in the intensity of convective heat transfer. Both experimental data and the numerical simulation results obtained with the use of OpenFOAM platform were used in the work. The investigations fulfilled will expand the area of the use of cyclone heating devices.

CONVECTIVE HEAT EXCHANGE ON THE LATERAL SURFACE OF A RELATIVELY LONG CYCLONE CHAMBER

The high-turbulent swirling flows of heat carrier that are created by a cyclone chamber are used in industry. They make it possible to intensify processes of heat and mass exchange. The results of an experimental study of convective heat transfer on the lateral surface of the active volume of a relatively long cyclone chamber considerably exceeding the length of the chambers that were used in previously performed studies are presented and analyzed in the article. Air supply in the swirler of the chamber was performed tangentially from diametrically opposite sides of the two input channels. The gas outlet was implemented from the opposite end. The heat transfer by convection to the swirling air flow was studied by the method of changing the state of aggregation of a heating agent – condensation of slightly superheated steam. Collecting condensate from the working section was made through a water seal for maintaining a constant pressure calorimeter. The amount of heat transferred during experiment was determined by weight of the collected condensate. The specific features of influence of geometrical characteristics of cyclone chamber on intensity of heat exchange are considered. In the experiments we varied the relative diameter of the outlet port of the chamber d вых and the relative area of the input channels f вх . Segmental construction of the chamber made it possible to move a calorimeter on its length. The local heat transfer coefficient was determined for various values of the dimensionless longitudinal coordinate z coinciding with the axis of the chamber, and counted from the back end of the swirler. The estimated equations of heat transfer obtained during the research are presented and recommended for use in practice of engineering. The considered problem is of an interest from the point of view of further research of aerodynamics and of convective heat transfer in a highly swirling flow cyclone devices, in order to improve the methods of their thermal and aerodynamic calculations.

Engineering of centrifugal dust-collectors based on parallel comparing tests applying computer modelling

Currently researchers are giving serious consideration to studying questions, related to issues of atmosphere protection, in particular, studying of new construction of gas-cleaning SPM cyclonic devices effectivity. Engineering new devices is impossible without applying mathematical model methods, computer modeling and making physical models of studying processes due nature tests.

新型机载多路音视频记录系统的设计与实现

Aiming at the requirements of high resolution, mass of data and high real-time performance for airborne multi-channel audio / video recording systems, a real-time multi-channel audio / video recording system was proposed based on embedded platform. Davinci video processors from Texas Instruments Incorporated( TI) were adopted to control the efficient real-time digitizing,coding and storage for fourchannel XGA( 1024 × 768@ 60 frames / s) videos, one channel PAL( 720 × 576@ 25 frames / s) video, and two-channel audios. Cyclone devices were exploited to transmit the compressed multimedia data. The testing results show that the system can implement recording and storage of multi-channel audio and video signal with high image resolution and good real-time performance. The system can find wide applications in the field of airborne recorders.

Energy Performance of Particle Settling in Cyclones

The most common way of how to purify gas from the solid and fluid air contaminant particles contained therein is the flow deformation and removal of particles under the action of inertial forces. This approach is realized in the cyclone system. To estimate the particles settling regularity and to optimize the construction of the cyclone device mathematic models of movement of particles in the rotational flow are used. Nowadays a number of mathematic models which describe this process are used. Normally the impact of the rotational flow turbulence is not taken into account in the existing models. Essentially new possibilities to estimate the particles settling regularity are provided by using the model of the turbulent diffusion with the finite velocity (DFV) which is demonstrated in the article.

Particles separation in a cyclone device cone

The improvement of the methods for calculating the efficiency for particles separation in these devices is the subject of article. Finding data show that the particles are discharged from the central zone to periphery by diffusive transport in the zone of high centripetal accelerations. It is found that the central zone is the ejection effect zone on the paraxial flow and intense discharge particle zone. The concentrations distribution and distribution of fractional efficiencies are presented.

Cyclone with Controlled Parameters and Self-Emptying Bin for Air Dedusting in Machine Building Plants

Efficiency of the dedusting of flue gases of the technological processes is reached at the expense of the new constructive solution of the cyclonic device in which possibility of the regulation of its geometrical parameters depending on properties and characteristics of the air-and-coal environment is provided. Results of pilot studies are presented, the engineering calculation procedure and a choice of the sizes of such devices is developed