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

2021 ◽  
pp. 48-54
Author(s):  
Volodymyr Maistruk
Keyword(s):  
Gas Flow ◽  
Radial Component ◽  
Tangential Component ◽  
Separation Process ◽  
Dust Removal ◽  
Dust Particles ◽  
Axial Component ◽  
Exhaust Pipe ◽  
Conical Part ◽  
Annular Space

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.

Investigations into Cyclone Dust Collectors

1949 ◽  
Vol 160 (1) ◽  
pp. 233-251 ◽  
Author(s):  
A. J. ter Linden
Keyword(s):  
Gas Flow ◽  
Vertical Component ◽  
Tangential Component ◽  
Dust Particles ◽  
Experimental Investigations ◽  
Entire Height ◽  
New Type ◽  
Total Velocity ◽  
Selection Of ◽  
Made In

The paper describes experimental investigations made in the mechanical engineering laboratory at Delft, in the field of cyclone separators. These investigations aimed first at determining the most efficient shape of a cyclone, by measuring the effect of a variation of each of its principal dimensions on the efficiency; as a result, a very efficient cyclone shape was developed. The influence of the position of a cyclone on the efficiency was examined, and a new type of cyclone with curved axis, horizontal gas exhaust, and vertical downward dust outlet was constructed. The flow of gas and dust inside a cyclone was examined. The static pressure and the three components of the gas velocity at different points in a cyclone were measured with a globe-Pitot tube. In a cyclone exhausting to atmosphere, a core of low pressure extends over the entire height of the cyclone. Inside this core the flow is very turbulent and unsteady, so that the gas velocities cannot be measured exactly; outside, the pressure is high throughout the remainder of the cyclone. With the exception of the turbulent area in the centre, the total velocity of the gas deviates only slightly from the tangential component V t, which increases as the distance from the centre of the cyclone diminishes. The vertical component V h is directed downwards along the cyclone walls and carries the dust particles to the bunker, and the radial velocity V r is directed towards the centre in the greater part of the cyclone; but in the very turbulent centre, V r is directed outwards and V h upwards. From these measurements a simple cyclone theory was developed, enabling the approximate calculation of the size of the largest dust particles that may escape a cyclone. The effect of a variation in the quantity of gas on the efficiency was determined; this effect was small for a well-constructed cyclone. Efficiencies are given for different sizes of similar shaped cyclones and for various sizes of dust particles. These data enable the selection of a cyclone collector suitable for a particular kind of dust, and the choice of cyclone dimensions for a given efficiency. A method of measuring the dust content of a gas-flow, by means of a small cyclone, is described.

scholarly journals Influence of elements thickness of separation devices on the finely dispersed particles collection efficiency

2018 ◽  
Vol 224 ◽  
pp. 02073 ◽  
Author(s):  
Andrey V. Dmitriev ◽  
Vadim E. Zinurov ◽  
Oksana S. Dmitrieva
Keyword(s):  
Flow Structure ◽  
Gas Flow ◽  
Collection Efficiency ◽  
Separation Process ◽  
Process Efficiency ◽  
Dust Particles ◽  
Optimum Thickness ◽  
Beam Elements ◽  
Dispersed Particles ◽  
Separation Devices

This article presents a rectangular separator, developed by the authors, for purification of a multiphase gas flow from the finely dispersed particles with a diameter of up to 10 µm. In order to increase the separation process efficiency, a research was conducted to determine the optimum thickness of I-beam elements within the separator at different values of the flow inlet rate and length of I-beam elements. It was found that change in the wall thickness of elements leads to a change in the flow structure, which causes a decrease in the dust particles collection efficiency.

Stress Tensor Measurements within the Vaneless Diffuser of a Centrifugal Compressor

1989 ◽  
Vol 203 (1) ◽  
pp. 51-59 ◽  
Author(s):  
T M A Maksoud ◽  
M W Johnson
Keyword(s):  
Centrifugal Compressor ◽  
Sampling Technique ◽  
Phase Lock Loop ◽  
Tangential Component ◽  
Secondary Flows ◽  
Axial Component ◽  
Reynolds Stresses ◽  
Vaneless Diffuser ◽  
Cross Sectional ◽  
Impeller Outlet

Distributions of normal and shear (Reynolds) stresses inside the vaneless diffuser of a low-speed centrifugal compressor are presented. The measurements were made using a triple hot-wire system and a phase lock loop sampling technique. Results were obtained on cross-sectional planes at eight radial stations between the impeller outlet and the diffuser exit at three different flowrates. The turbulence was highly anisotropic and became more so as the flowrate was increased. The tangential component of turbulent intensity was found to be significantly smaller than either the radial or axial component. The blade wake observed at the diffuser inlet decays very rapidly due to the strong tangential Reynolds stresses generated by the opposed secondary flows on either side of the wake. The passage wake decays very much more slowly and is still identifiable at the diffuser discharge.

Conjoint Analysis of Focusing Field Characteristics of Radially Polarized Beams Based on LabVIEW and MATLAB

2014 ◽  
Vol 651-653 ◽  
pp. 2414-2417
Author(s):  
Xiao Qing Zhang ◽  
Yu Dong Jia ◽  
Fu Rong Du
Keyword(s):  
Conjoint Analysis ◽  
Radial Component ◽  
Axial Component ◽  
Analysis Method ◽  
Characteristic Analysis ◽  
Polarized Beams ◽  
Matlab Program ◽  
Late Application ◽  
Beam Transmission ◽  
Radially Polarized

For the aim of analyzing focusing field characteristics of radially polarized beams, a conjoint analyzing method is presented based on LabVIEW and MATLAB. The main program is programmed in the LabVIEW environment, connecting with MATLAB program through ActiveX control. Experimental results show that the strength of the radial component in the center is zero and the strength of the axial component in the center is the largest. The conjoint analysis method realized characteristic analysis of focusing field for radially polarized beams, laying the groundwork for beam transmission of the late application.

Wet Steam Nonequilibrium Condensation Flow-Induced Vibrations of a Nuclear Turbine Blade

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Bing Guo ◽  
Weixiao Tang
Keyword(s):  
Rotor Blade ◽  
Virtual Work ◽  
Pressure Fluctuations ◽  
Tangential Component ◽  
Axial Component ◽  
Flow Induced Vibration ◽  
Blade Vibration ◽  
Vibration Responses ◽  
Nonequilibrium Condensation ◽  
Equivalent Load

Condensing flow induced vibration (CFIV) of the rotor blade is a tough problem for designers of nuclear turbines because nonequilibrium condensing flow excitation (NECFE) is hard to be directly modeled. Generally, in design, NECFE is assumed as equilibrium condensing flow excitation (ECFE), of which the pressure fluctuations caused by phase temperature difference (PTD) between gaseous and liquid are ignored. In this paper, a novel method to calculate the equivalent load of NECFE based on the principle of virtual work was proposed. This method could consider the effects of PTD-induced pressure fluctuations by simulating nonequilibrium condensation with ANSYS cfx, and improve computational efficiency. Once the equivalent NECFE load is determined, CFIV of the rotor blade, which was modeled as a pretwisted asymmetric cantilever beam, can then be predicted by the finite element method (FEM). Additionally, to estimate the effects of PTD-induced pressure fluctuations, comparisons between NECFE and ECFE as well as their induced vibrations were presented. Results show that PTD in nucleation area could change the position and type of shock waves, restructure the pressure distribution, as well as enhance the pressure fluctuations. Compared with ECFE, the frequency ingredients and amplitude of the equivalent NECFE load and its induced vibrations are increased. Specifically, the amplitude of the equivalent NECFE load is increased by 9.38%, 15.34%, and 7.43% in the tangential component, axial component, and torsion moment. The blade vibration responses induced by NECFE are increased by 11.66% and 19.94% in tangential and axial.

scholarly journals One-Dimensional Gas Flow Analysis of the Intake and Exhaust System of a Single Cylinder Diesel Engine

2020 ◽  
Vol 8 (12) ◽  
pp. 1036
Author(s):  
Kyong-Hyon Kim ◽  
Kyeong-Ju Kong
Keyword(s):  
Diesel Engine ◽  
Gas Flow ◽  
Discharge Coefficient ◽  
Flow Analysis ◽  
Exhaust System ◽  
Maximum Pressure ◽  
Exhaust Pipe ◽  
One Dimensional ◽  
Average Mass ◽  
Bent Pipe

In order to design a diesel engine system and to predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. Gas flow analysis in a three-dimensional (3D) format needs a high-resolution workstation and an enormous amount of time for analysis. Calculation using the method of characteristics (MOC), which is a gas flow analysis in a one-dimensional (1D) format, has a fast calculation time and can be analyzed with a low-resolution workstation. However, there is a problem with poor accuracy in certain areas. It was assumed that the reason was that 1D could not implement the shape. The error that occurs in the shape of the bent pipe used in the intake and exhaust ports of the diesel engine was analyzed and to find a solution to the low accuracy, the results of the experiment and 1D analysis were compared. The discharge coefficient was calculated using the average mass flow rate, and as a result of applying it, the accuracy was improved for the maximum negative pressure by 0.56–1.93% and the maximum pressure by 3.11–7.86% among the intake pipe pressure results. The difference in phase of the exhaust pipe pressure did not improve. It is considered as a limitation of 1D analysis that does not improve even by applying the discharge coefficient. In the future, we intend to implement a bent pipe that cannot be realized in 1D using a 3D format and to prepare a method to supplement the reliability by using 1D–3D coupling.

Performance of Fractional-Slot Winding PM Machines due to Un-even Coil Turns and Asymmetric Design of Stator Teeth

2015 ◽  
Vol 6 (4) ◽  
pp. 853
Author(s):  
Mohd Luqman Mohd Jamil ◽  
Syed Muhammad S. A. Al-Habshi ◽  
Md Nazri Othman ◽  
Tole Sutikno
Keyword(s):  
Finite Element Analysis ◽  
Magnetic Force ◽  
Radial Component ◽  
Tangential Component ◽  
Slight Reduction ◽  
Element Analysis ◽  
Electromagnetic Performance ◽  
Asymmetric Winding ◽  
Number Combination ◽  
Fractional Slot

PM machines in which slot number and pole number combination differs by one have to be configured with asymmetric winding pattern in order to maximize it back-emf performance. However, this asymmetric winding configuration inherently results an unwanted Unabalanced Magnetic Force (UMF). Investigations of electromagnetic performance of fractional-slot asymmetric winding PM machines using 2-D Finite-Element Analysis are presented. The investigations are mainly driven by the effort of minimizing the UMF. By employing techniques such as non-uniform number of coil turns in every tooth and asymmetric design of stator tooth, the UMF are expected can be minimized. The investigations show that the radial component of UMF has greater effect than the tangential component on the UMF itself. In all proposed techniques, a slight reduction of machine torque performance is inevitable.

scholarly journals Theoretical and experimental study on a finite size vector sensor array with a cylindrically symmetric carrier

2019 ◽  
Vol 283 ◽  
pp. 07008
Author(s):  
Junyuan Guo ◽  
Shi-e Yang ◽  
Hongjuan Chen ◽  
Shengchun Piao ◽  
Longhao Qiu
Keyword(s):  
Finite Size ◽  
Low Frequency ◽  
Doa Estimation ◽  
Radial Component ◽  
Tangential Component ◽  
Low Frequencies ◽  
Cylindrically Symmetric ◽  
Noise Characteristics ◽  
Vector Sensor ◽  
Array Gain

In this work, a finite size acoustic vector sensor (AVS) array is designed and its performance is theoretically and experimentally studied. The two-dimensional AVS array is comprised of five vector sensors and configured as a cross, and the array carrier is a cylindrically symmetric structure. Theoretical analysis and simulation indicate that the proposed method considering structure scattering can widen the working bandwidth. Furthermore, the utilization of vector sensor enables a significant white noise gain improvement at low frequencies, which makes the array more robust and easier to realize. Experiments have been done to study the array performance from several aspects including sensor noise characteristics, the beampattern, the direction-of-arrival (DOA) estimation ability and the array gain. From the change of the sensor directivity patterns or the amplitude distortion of the noise field, we can clearly observe the scattering field intensity. Moreover, it shows that the influence of the structure scattering on the tangential component of the vector field is symmetric, while that of the radial component is asymmetric. Experimental results also demonstrate that, with the proposed method, the 2nd and the 3rd order beamformers can be obtained which could be further used for the estimation of target DOA. In addition, an array gain of at least 6 dB is obtained capable of detection of weak signals. Our results indicate that the proposed array with a physical size less than one meter, although affected by nearby scatterers, can effectively break the Rayleigh limit and realize the remote detection in low-frequency regime.

Laser Measurements of Fly Ash Rebound Parameters for Use in Trajectory Calculations

1987 ◽  
Vol 109 (4) ◽  
pp. 535-540 ◽  
Author(s):  
W. Tabakoff ◽  
M. F. Malak
Keyword(s):  
Gas Flow ◽  
Initial Conditions ◽  
Incidence Angle ◽  
Equations Of Motion ◽  
Solid Particles ◽  
Dust Particles ◽  
Laser Doppler Velocimeter ◽  
Laser Measurements ◽  
Flow Through ◽  
Small Dust

This paper describes an experimental method used to find particle restitution coefficients. The equations that govern the motion of solid particles suspended by a compressible gas flow through a turbomachine depend on the restitution coefficients. Analysis of the data obtained by a laser-Doppler velocimeter (LDV) system of the collision phenomenon gives the restitution ratios as a function of the incidence angle. From these ratios, the particle velocity components after collision are computed and used as the initial conditions to the solution of the governing equations of motion for particle trajectories. The erosion of metals impacted by small dust particles can be calculated by knowing the restitution coefficients. The alloy used in this investigation was 410 stainless steel.

scholarly journals Flow Downstream of a Cluster of Nine Jets

2006 ◽  
Vol 129 (5) ◽  
pp. 541-550 ◽  
Author(s):  
M. Boutazakhti ◽  
P. E. Sullivan ◽  
M. J. Thomson ◽  
I. Yimer
Keyword(s):  
Radial Component ◽  
Axial Component ◽  
Atmospheric Conditions ◽  
Jet Interaction ◽  
Air Jets ◽  
Air Stream ◽  
Low Emission ◽  
Image Velocimetry ◽  
Single Jet ◽  
Self Similar

This work is an experimental investigation of the flow downstream of a low emission nozzle. The nozzle is a 3×3 square matrix of nine small swirling air jets, has a design swirl number of 0.8, and operates at a Reynolds number of 40,000. Particle image velocimetry (PIV) was used to map the velocity field under nonburning and atmospheric conditions for the first 18 jet diameters downstream of the nozzle exit plane. Seeding was liquid injected into the air stream and drops were sized to filter out those larger than 3×3pixels. The results showed that the cluster blends into a single jet-like flow 12 jet diameters downstream with the axial component of the velocity displaying self-similar properties. Lateral jet interaction slows the decay of the axial component of the velocity and jet expansion in the developed region while accelerating the decay of the radial component.

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