Cyclonic Chamber Research Articles

Design and performance research of cyclonic mechanical gripper

To achieve effective gripping of large planar and flexible targets while reducing the risk of scratching, a novel cyclonic-type mechanical gripper based on rotating blades is studied. Firstly, the working principle of this cyclonic gripper is analyzed in detail, followed by the structural design of the gripper unit. Using Fluent computational fluid dynamics software, the flow characteristics of the airflow within the cyclonic gripper chamber are analyzed, and the influence of gripper structural parameters on suction force is investigated. Finally, a suction force testing platform for the cyclonic gripper is constructed, and experimental validation of the simulated suction force results is conducted. The research indicate that the proposed cyclonic-type mechanical gripper based on rotating blades can effectively grip targets, while the suction force is closely related to parameters such as blade rotation speed, number, and diameter.

Numerical investigation of premixed combustion of producer gas with hydrogen injection in a cyclonical chamber

ABSTRACT This paper employs computational fluid dynamics (CFD) simulations with an eddy dissipation concept model (EDC) and a skeletal reaction mechanism (SK17) to analyze the impact of hydrogen addition on the premixed combustion mode of producer gas (PG) fuel in a cyclonic flow combustion chamber. The results, validated against measured wall temperature data, demonstrate a minor discrepancy between simulation and experiment. The studied result showed that injection of hydrogen into PG fuel combustion elevates the temperature of the combustion process, which can be indicated by the average temperature across the combustion chamber, outlet temperature of exhaust gas, and reactive radical species. However, increasing H2 injection over 20% results in strongly increasing CO formations. Compared to a fixed thermal input case, hydrogen injection with a variable input power resulted in a higher combustion temperature and increased emissions of both CO and NO. The maximum CO emission reached approximately 1246 ppm, while NO peaked at around 75 ppm, both observed at a 30% hydrogen injection rate. The key finding of this study revealed that direct injection of hydrogen to the combustion under the condition of a given equivalence ratio is unfavorable due to insufficient oxygen for the reaction, leading to an increase in CO emissions. The optimal condition would be a hydrogen injection below 20%, which produces low CO and NO emissions.

A mechanistic analysis of particle flow in a pulsatile circulating dual fluidized bed for chemical looping technology based on CDF-DEM simulation

This paper presents a three-dimensional computational fluid dynamic–discrete element method (CFD-DEM) model using Geldart class D particles for studying the fluid flow pattern in a circulating dual fluidized bed (CDFB) for chemical looping dry reforming of methane (CLDRM). The system design comprised a high-velocity air reactor (AR) also known as riser fluidized bed, a riser tube, a cyclone chamber, a fluidizing bed fuel reactor (FR), and a connecting loop, which closes the loop between AR and FR. The particles distribution, volume fraction, flow pattern, velocity and their circulation between the AR (riser) and FR (second fluidized bed) in CDFB were deeply investigated. The results showed that the CLDRM system experiences a pressure imbalance between the reduction and oxidation zones, causing solid particles to undergo a highly intricate and turbulent pulse flow. As a result, the operation of the system is alternately governed by two flow regimes: bubbling fluidization and pulsatile circulating fluidization. The burst of a high pressure pulses provide the pressure head required for circulation of the particles. The pulses also led to the intermittent transportation of particles ― in the form of particles clusters ― from high-pressure area to the region with a lower pressure.

Hydrodynamics of a Cyclone Chamber with a Varying Direction of Tangential Blowing

Hydrodynamics of a Cyclone Chamber with a Varying Direction of Tangential Blowing

Minimization of Energy Consumption of Vortex Devices for Granulation of Materials

The article considers the possibility of efficient energy and environmental use of vortex devices for the granulation of solids. The factors influencing the energy consumption for generating a vortex flow with dispersed solid inclusions are analysed. A mathematical model for calculating the aerodynamic drag of a vortex apparatus in a clean gas flow, which was used in computer modelling, is presented. The main dependencies for determining the influence of the geometric dimensions of the vortex on its aerodynamic drag are also given. An analytical solution to the problem of minimising the aerodynamic drag of a vortex apparatus during the movement of a dispersed medium is considered. The forces acting on the particles in the cyclone chamber during interaction with the gas are analysed. In this paper, a general method for calculating the parameters of cyclone-vortex devices for dispersed media using the basic equations of hydrodynamics and gas dynamics is developed. The solution approach used in this paper can be extended to other vortex devices not considered in this work.

Numerical CFD Simulation of a Horizontal Cyclonic Combustion Chamber for Burning Pulverized Biomass Solid Fuels

Numerical CFD Simulation of a Horizontal Cyclonic Combustion Chamber for Burning Pulverized Biomass Solid Fuels

Experimental study on the separation performance of a novel gas–liquid separator

• A dynamic gas–liquid separator called high-gravity cyclone separator (HGCS) has been designed. • A high-gravity environment is created by the strengthened centrifugal force in the rotary drum. • The performance, including the efficiency and pressure drop, is experimentally investigated. • The effects of the operating conditions and drum structure parameters are evaluated. A novel two-stage dynamic separator called high-gravity cyclone separator (HGCS) has been designed for gas–liquid separation. It is mainly composed of a cyclone chamber and rotary drum. In this study, its performance, including the separation efficiency and pressure drop, is experimentally investigated, and the effects of the operating conditions and drum parameters are evaluated. For droplets with a mean diameter of 7 μm, the results indicate that the optimal gas inlet velocity and high-gravity factor are 12 m/s and 59.4, respectively, and the separation efficiency reaches 98 %. The effect of liquid concentration is sensitive to the high-gravity factor. At a liquid concentration of 57 g/m 3 , the maximum efficiency will be 98.75 % when increasing the high-gravity factor to 85.6. Furthermore, a smaller radial height is preferable when the gas inlet velocity is greater than 12 m/s, and a better separation efficiency can be obtained by increasing the drum length to 190 mm. However, when the length is 235 mm, the efficiency will be poor because of the Kelvin–Helmholtz and Rayleigh–Taylor instabilities. Compared with the predominant roles of gas inlet velocity, drum length and radial height in pressure drop, the effects of liquid concentration and high-gravity factor are small.

Production of Inhalable Ultra-Small Particles for Delivery of Anti-Inflammation Medicine via a Table-Top Microdevice.

A table-top microdevice was introduced in this work to produce ultrasmall particles for drug delivery via inhalation. The design and operation are similar to that of spray-drying equipment used in industry, but the device itself is much smaller and more portable in size, simpler to operate and more economical. More importantly, the device enables more accurate control over particle size. Using Flavopiridol, an anti-inflammation medication, formulations have been developed to produce inhalable particles for pulmonary delivery. A solution containing the desired components forms droplets by passing through an array of micro-apertures that vibrate via a piezo-electrical driver. High-purity nitrogen gas was introduced and flew through the designed path, which included the funnel collection and cyclone chamber, and finally was pumped away. The gas carried and dried the micronized liquid droplets along the pathway, leading to the precipitation of dry solid microparticles. The formation of the cyclone was essential to assure the sufficient travel path length of the liquid droplets to allow drying. Synthesis parameters were optimized to produce microparticles, whose morphology, size, physio-chemical properties, and release profiles met the criteria for inhalation. Bioactivity assays have revealed a high degree of anti-inflammation. The above-mentioned approach enabled the production of inhalable particles in research laboratories in general, using the simple table-top microdevice. The microparticles enable the inhalable delivery of anti-inflammation medicine to the lungs, thus providing treatment for diseases such as pulmonary fibrosis and COVID-19.

An experimental and modelling study of the Selective Non-Catalytic Reduction (SNCR) of NOx and NH3 in a cyclone reactor

The Selective Non-Catalytic Reduction process was investigated through experiments and modelling in a bench scale cyclone reactor. Outlet and internal profiles of NO and NH3 concentrations were measured at varying operating conditions. Cyclone inlet temperatures between 866 and 1023 °C were used, while the inlet NO concentration was kept at ~500 ppm. Gaseous ammonia was injected in the cyclone inlet, with nitrogen carrier gas. 60–69% NO reduction was achieved at inlet temperatures of 975–982 °C, and stoichiometric ratio NH3/NO β≈1.6, with no ammonia slip. The main reaction zone was the inlet and upper cyclone chamber. The experiments was modelled using simple and detailed kinetics combined with simple reactor models and a compartment model suggested in this work. The qualitative trends of NO reduction and ammonia slip were predicted by the models. However, the ammonia slip was significantly over-predicted in most cases. The outlet concentrations were insensitive to choice of reactor model, while sensitive to temperature and kinetics. The compartment model quantitatively reproduced the cyclones NO concentration profiles, through its simplified representation of the cyclone flow and temperature gradients, while the NH3 profiles were only qualitatively predicted. The choice of bypass fractions showed a large influence on the ammonia profiles.

On the generalized Beltramian motion of the bidirectional vortex in a conical cyclone

This work presents an exact solution of Euler's incompressible equations in the context of a bidirectional vortex evolving inside a conically shaped cyclonic chamber. The corresponding helical flowfield is modeled under inviscid conditions assuming constant angular momentum. By leveraging the axisymmetric nature of the problem, a steady-state solution of the generalized Beltramian type is obtained directly from first principles, namely, from the Bragg–Hawthorne equation in spherical coordinates. The resulting stream function representation enables us to fully describe the ensuing swirl-dominated motion including its fundamental flow characteristics. After identifying an isolated singularity that appears at a cone divergence half-angle of 63.43°, two piecewise formulations are provided that correspond to either fluid injection or extraction at the top section of the conical cyclone. In this process, analytical expressions are readily retrieved for the three velocity components, vorticity, and pressure. Other essential flow indicators, such as the theoretically preferred mantle orientation, the empirically favored locus of zero vertical velocity, the maximum polar and axial velocities, the crossflow velocity, and other such terms, are systematically deduced. Results are validated using limiting process verifications and comparisons to both numerical and experimental measurements. The subtle differences between the present model and a strictly Beltramian flowfield are also highlighted and discussed. The conically cyclonic configuration considered here is relevant to propulsive devices, such as vortex-fired liquid rocket engines with tapered walls; meteorological phenomena, such as tornadoes, dust devils, and fire whirls; and industrial contraptions, such as cyclonic flow separators, collectors, centrifuges, boilers, vacuum cleaners, cement grinders, and so on.

Increasing the efficiency of burning solid fuel in the layer

he main directions of increasing the efficiency of solid fuel heat generators are analyzed. It is noted that in industrial designs of heat generating installations depending on their class technological schemes of burning of solid fuel are applied at various levels on capital and operational expenses. The most expensive are the technologies of combustion of pre-prepared high-quality fuel in heat generators with complex mechanization at all stages of the combustion process, which provide high thermal and environmental performance. Cheaper combustion technologies are widespread, according to which the normative performance of heat generators is achieved due to the rational ratio of design and mode parameters of the combustion zone with the thermophysical characteristics of the burned fuel, including low-grade. Examples of realization of such technological schemes of combustion on the basis of results of theoretical and experimental researches in designs of solid propellant heat generators are resulted. The paper proposes a constructive scheme of a small-capacity heat generator with a combined technology of two-chamber solid fuel combustion, in which a layered (or shaft-layered) combustion process with combustion in volume is combined: in the primary combustion chamber above the burning fuel layer on the grate, and in the secondary cyclone chamber (or cameras). Due to the vortex motion in the lined secondary chamber of high-temperature gases containing solid particles carried by the flow from the combustion zone of the primary chamber, there is both afterburning of combustible substances and separation of ash particles with their discharge into the ash generator. This combustion technology also allows increasing the forcing of the combustion layer on the grate, increasing the stability of the process and reducing the dimensions of the structure. Improving the efficiency of a solid fuel heat generator with a two-chamber furnace is achieved by reducing heat loss with mechanical incomplete combustion of carbon particles in the exhaust gases, as well as reducing the concentration of ash particles in the gas stream at the inlet of convective heat exchange surfaces and increase their thermal efficiency. This is confirmed by the calculated dependences of the efficiency of the mechanized solid fuel heat generator under different technological schemes of solid fuel combustion

Aerodynamics and convective heat transfer processes in cyclone chambers with external recirculation of gases

The paper presents the results of an experimental and theoretical calculation study of aerodynamics and convective heat transfer on the side surface of cyclone recirculation furnace devices. The possibility of controlling the main aerodynamic characteristics without changing the geometric parameters of the cyclone devices by organizing external gas recirculation is shown.

Numerical and experimental analysis of vertically ascending swirling liquid film flow

Free-surface flows belong to an important class of two-phase flows in fluid mechanics. During the process of production and extraction of oil in the petroleum industry, a thin film of liquid builds up on either horizontal or vertical surfaces in several stages of the oil production. This type of flow is known as two-phase liquid film flow. The present work describes an analysis on the development of a liquid film in an upward flow under the action of centrifugal and gravitational fields (swirling flow) in a cyclonic chamber of a distribution system. In this article, the dynamics of a liquid film flow is analyzed with the aid of three-dimensional and transient numerical simulations. A numerical model was developed and validated with experimental data with a 17.5% mean difference. A Euler-Euler two-fluid model coupled with the compressive discretization scheme for the capture of the liquid-gas interface and the Shear Stress Transport turbulence model was used to model the flow numerically. The finite volume method was used to discretize the conservation equations. The results obtained added to the current knowledge on flow dynamics (formation, spreading, stability and development) and on how the superficial velocities of liquid and gas influence the stability and behavior of the vertically ascendant liquid film flow. Liquid films flow with smaller thicknesses causing smaller fluctuations in the flow, thus leading to a homogeneous distribution of the flow at the outlet of the equipment.

An exact irrotational solution for a hemispherically bounded cyclonic flowfield

This study focuses on the development of an internal potential flow solution in the context of a hemispherically bounded cyclonic chamber. The analysis proceeds from the Bragg–Hawthorne equation, which is quite effective in the treatment of steady, inviscid, and axisymmetric flows when expressed in terms of the streamfunction. Once the streamfunction is obtained, other flow properties are readily deduced; these include the principal velocity and pressure distributions, swirl intensity, crossflow velocity, and mantle location. Furthermore, given the overarching spherical geometry, two different types of mantles are identified and related to the coexistence of axially bidirectional and circularly bipolar regions. The first, axial mantle, which is traditionally used in the analysis of cylindrical and conical cyclone separators, consists of a rotating, non-translating interfacial layer along which the axial velocity vanishes. It thus separates the outer, vertical updraft, from the inner, swirling downdraft. The second, polar mantle, which arises in the context of a hemispherical flow configuration, coincides with the spherical interface along which the polar velocity vanishes. It hence partitions the flow domain into a much larger outer region, where the flow direction remains strictly counterclockwise, and a proportionally smaller inner region, where the outflow becomes clockwise. Despite their dissimilar structures, both axial and polar mantles meet in the exit plane at a fractional radius of 1/e2 or 13.53%. In this study, the unique characteristics of the resulting irrotational motion, which reduces to a continuously looping, hemispherically cyclonic potential vortex, are evaluated and discussed.

Premixed combustion of producer gas in a cyclonic flow combustion chamber under varying number of burners

ABSTRACT Producer gas derived from biomass gasification can be used as an alternative to fossil fuel for generating power. Low heating value and high CO content are main obstacles for using it via a combustion process, leading to require a special combustor design to achieve its efficient burning. This study aims to investigate premixed combustion characteristics of producer gas in a cyclonic flow combustion chamber under varying from single to four burners using 3D computational fluid dynamics simulation. Combustion process is operated at fixed thermal power input of about 90 kW with respect to injection of air-fuel mixture at the ambient condition. A 17 species skeletal reaction scheme with 73 chemical reversible reactions is used for chemical interactions. The numerical result is well agreed with the experimental data. Through all studied results it could be concluded that the peak combustion temperature, which is higher than 1600 K, is obtained for the case of multiple burners, except for the single burner case. The lowest CO formation is obtained for the case of four burners, which is approximately 243 ppm while lowest NO formation is obtained for the single burner case, which is approximately 17 ppm.

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.

On the substantiation of the effectiveness of air-centrifugal separation and dust cleaning of seed heap of herbs after the grate device

The agrobiological and physico-mechanical properties of leguminous seed plants do not allow them to be harvested without loss exclusively by combine technologies. One way to increase the productivity of the seed production process is to include stationary machines in the assembly technology for wiping and separating seed heaps. Combining these important operations with one machine will further increase the efficiency of legume seed production technologies. This work is devoted to considering ways to increase the efficiency of air-centrifugal separation and dust cleaning seed heaps. A review of recent studies and publications has shown that there is a sufficient methodological basis for determining the parameters of the process of separation of the heap and purification of the exhaust air. An analysis of the publications made it possible to determine the purpose of the research, which is to increase the efficiency of the grater-separation unit by substantiating its scheme and the method of theoretical determination of the parameters of the separation process. According to the results of previous studies, a structural scheme of the grater-separating device is proposed. The main elements of the block are a grater device, which consists of a motionless and movable corrugated discs of the separating device with separate channels for the exit of seeds, straw part of the heap, air. To increase the efficiency of the cleaning process, a blade swirler and a louvre nozzle are placed in the separating device, which provide the air flow with rotational movement around the axis of the cyclone body. In theoretical studies of the motion of particles in a rotational air flow, the simplified assumption was adopted: the particles are spherical, do not deform, and do not interact with each other, the inertia force is directed along the radius of the cyclonic chamber, the tangential and axial components of the particle velocity are equal to the corresponding components of the air velocity, and the particle resistance force determined by the Stokes law, the force of attraction is much less than the centrifugal force, so we neglect it. The obtained formulas allow one to approximately determine the parameters of the cyclone device that will ensure the separation of the seeds of legumes.

Multiple Wire-Mesh Sensors Applied to the Characterization of Two-Phase Flow inside a Cyclonic Flow Distribution System.

Wire-mesh sensors are used to determine the phase fraction of gas–liquid two-phase flow in many industrial applications. In this paper, we report the use of the sensor to study the flow behavior inside an offshore oil and gas industry device for subsea phase separation. The study focused on the behavior of gas–liquid slug flow inside a flow distribution device with four outlets, which is part of the subsea phase separator system. The void fraction profile and the flow symmetry across the outlets were investigated using tomographic wire-mesh sensors and a camera. Results showed an ascendant liquid film in the cyclonic chamber with the gas phase at the center of the pipe generating a symmetrical flow. Dispersed bubbles coalesced into a gas vortex due to the centrifugal force inside the cyclonic chamber. The behavior favored the separation of smaller bubbles from the liquid bulk, which was an important parameter for gas-liquid separator sizing. The void fraction analysis of the outlets showed an even flow distribution with less than 10% difference, which was a satisfactorily result that may contribute to a reduction on the subsea gas–liquid separators size. From the outcomes of this study, detailed information regarding this type of flow distribution system was extracted. Thereby, wire-mesh sensors were successfully applied to investigate a new type of equipment for the offshore oil and gas industry.

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.

Effect of the inlet duct angle on the performance of cyclone separators

This study analyzed the effect of the angle of the inlet duct bend on the separation efficiency and pressure drop in cyclone separators. The design of the inlet to the cyclone chamber is a significant parameter that has been analyzed to date only in a few research studies. Following the literature review of this subject, 20 bend angles (10 in the vertical plane and 10 in the horizontal plane) were proposed and analyzed by means of the computational fluid dynamics code Fluent V18.2. As a closure model to the Reynolds-averaged Navier–Stokes equation, the Reynolds stress model was used, as it solves the transport equations for Reynold’s stresses and the dissipation rate - this model is capable of accounting highly curved streamlines prevailing inside the cyclone separators. The discrete phase model with one-way coupling was used, in which the trajectory of solid particles was calculated based on Lagrangian formulation. Conclusive results indicate that the bend angle (in both planes) marginally affects the collection efficiency (the maximum difference being 3.1%), whereas its effect on Eu is highly significant (the difference being 5700%) - all the comparisons were made with respect to the base variant at 0° angle.