Drum Length Research Articles

Prediction of rod-like particle mixing in rotary drums by three machine learning methods based on DEM simulation data

The mixing of non-spherical particles in rotary drums exhibits significant complexity, particularly when density segregation and size segregation occur simultaneously. Three machine learning models: artificial neural network (ANN), extremely randomized trees (ERT), and particle swarm optimized support vector regression (PSO-SVR) were developed to predict the mixing time and mixing degree at the steady mixing state of rod-like particles in rotary drums. The training, validation, and test data for the machine learning models were generated from 121 discrete element method (DEM) simulations with four independent variables: revolution frequency, particle density ratio, particle size ratio, and drum length. All three models predicted the mixing degree accurately with R2≥ 0.94. The ERT and PSO-SVR models also predicted the mixing time well with R2≥ 0.88. Building machine learning models is hundreds of times faster than running DEM simulations, making these models highly promising for predicting larger-scale simulations with more complex-shaped particles.

Segregation flow behavior of polydisperse particle mixture with skewed distribution in a rotating drum

Industrial particle mixtures are naturally polydisperse due to the variations in size distribution during mineral processing, which makes it necessary to investigate segregation behaviors of polydisperse particle mixtures. In this work, five groups of polydisperse particle mixtures were defined separately by different skewed distributions. Based on discrete element method, the polydisperse particle segregation behaviors of in rotary drums were simulated. The results indicate that in the polydisperse particle system with normal distribution, larger particles tend to accumulate towards the both sides, while smaller particles tend to be in the middle of the drum. In this case, the medium-sized particles are uniformly distributed throughout the system. However, once the polydisperse particle mixture transitions from the coarse particle to the fine particle system, the size of medium particles exhibiting uniform distribution characteristics decreases with an increase in the skewness coefficient. Moreover, the smaller the skewness coefficient of the polydisperse particles, the slower the initial particle segregation rate, and the lower the steady particle segregation degree. Furthermore, whether the drum length to diameter (L / D) ratio or drum filling rate increases, the particle segregation rate in initial stage and the particle segregation degree in steady stage are subsequently significantly reduced, while the size of medium particles with uniform distribution characteristics remains essentially constant.

Prediction of particle mixing in rotary drums by a DEM data-driven PSO-SVR model

Particle mixing in rotary drums is of significant industrial importance, but very complex. Detailed simulation can be achieved using the discrete element method (DEM), but the computational time cost is enormous. Therefore, we combined machine learning with DEM simulations and established a DEM data-driven particle swarm optimization and support vector regression (PSO-SVR) model to predict mixing time and mixing degree at steady mixing state for binary sphere mixtures in horizontal rotary drums with four independent variables: revolution frequency, particle density ratio, particle size ratio, and drum length. After hyperparameter tuning by PSO on a validation set of 25 simulations, the SVR model was trained on 81 DEM simulations. Testing on another 25 simulations yielded excellent results with R2 = 0.95 for mixing time and R2 = 0.90 for mixing degree. These results indicate that the PSO-SVR model is suitable for rapid predictions of particle mixing in rotary drums and other particle processing equipment.

Analysis of the problems of using disc brakes in the complex of long drums of mine hoists with increased rope capacity

Purpose. After analysing the current literature in the field of mine hoisting, to determine the prospects for the use of disc brakes in a complex of mine hoisting machines with increased rope capacity with a long cylindrical cutter drum. To identify the problems associated with the end runout of the sheath and an increase in the deviation angle that arise when operating drums with a long casing in order to optimise their use. The methods. The study identifies the problems of using disc brakes in combination with long drums of increased rope capacity, as well as the associated increase in the value of the deviation angle and the length of the rope string. A computer experiment was carried out to find the dependence of the end runout of the sheath on its length under the action of a steady external pressure modelling the operation of a coiled rope, using the example of the sheath of the drum TsR-6.75×6.2/1.95. Findings. The article considers the problem of stiffness of long drums of hoisting machines, the increase in length of which occurs due to the increase in the depth of extraction, as well as the use of disc brakes in such hoisting machines. A computer experiment has been conducted to determine the dependence of face runout on the length of the hoisting machine drum shell. Thus, with the lengthening of the shell, the end runout increases, which can interfere with the safe operation of the disc brake. The originality. For the first time, a calculation methodology for determining the axial stiffness of long drums of mine hoists with increased rope capacity was developed and substantiated using the example of the drum of the TsR-6.75×6.2/1.95 machine with the help of the SolidWorks and MathCAD software complex. Generalisation of data on the relationship between drum length and deviation angle, which are critical for the safety and efficiency of mine hoists. Practical implementation. The implementation of the methodology will solve the problems with the use of disc brakes in the complex of mine hoists with long cylindrical drums of increased rope capacity, namely, with the end runout of brake discs, as well as an increase in the value of the deviation angle, increasing the efficiency and safety of mine hoists. This will eliminate the need to install additional support supports when lengthening the rope string to prevent longitudinal and, as a result, transverse vibrations. Ensure more stable and safe operation of mine hoists by optimising the design and braking systems.

DESIGN OF A 10 TONS OVERHEAD CRANE WITH 21 METERS SPAN USING FINITE ELEMENT METHOD

A crane is a lifting equipment widely used to move cargo, construction sites, storage, and unload. The type of crane that is commonly used in industrial environments is the overhead crane. The overhead crane functions as a lifting device. Besides that, it also works as a load transfer tool even though the load being moved is limited to an environment that is not too large (indoor) at PT. A overhead crane is designed to overcome the problem of moving material in the mold storage area due to the area's expansion and the addition of 5-7 tons of mold material. Therefore, proper design is needed so the overhead crane can function properly. The design method uses the VDI 2221 or Finite Element with Solid works software. The results of the structure obtained are double box girder type girders with dimensions p = 21 m, t = 1224 mm, and l = 600 mm. The deflection results are 13.75 mm, and the runway uses steel profile I with dimensions 400 x 200 x 8 x 13 mm, with a deflection value at the runway stem of 5.6 mm. The type of wire rope used is type 6 x 37, with a diameter of 28 mm. The stress that occurs in the steel rope is 4306.1 Kg, less than the maximum allowable tensile stress of 8009.4 Kg. The single hook type with a hook diameter of 120 mm is made of material S45C. The tensile stress on the hook is 0.88 Kg, and the result is smaller than the allowable tensile stress of 12.72 Kg. The pulley diameter is 630 mm, the drum diameter is 604.9 mm, and the drum length is 279 mm.

Double-layered granular soil modulus extraction for intelligent compaction using extended support vector machine learning considering soil-structure interaction

Intelligent Compaction (IC) has been acquiring a growing interest in real-time quality control of compacted soil layers because of its high efficiency and full-area coverage. The current intelligent compaction technology allows the determination of the uniformity level of compaction over large areas according to the dynamic response of the roller. However, accurate real-time determination of the soil modulus during compaction based on roller acceleration has been challenging due to the multi-layered composite nature of the soil and the nonlinearities of the governing dynamic equations of motion and soil response. This study adopts a double-layered soil profile, and a three-dimensional finite element model, accounting for soil-drum interaction, is utilised for the analysis. The isotropic hardening elastoplastic hysteretic model was implemented to simulate the soil behaviour subjected to cyclic loading ranging from small to large strain amplitudes and account for stiffness degradation. The comprehensive dataset composed of the roller acceleration response and ground characteristics is then used to correlate the predicted soil modulus via an advanced machine learning approach. The adopted machine learning method incorporating Gaussian Kernel and Generalised Gegenbauer Kernel functions can reasonably predict the double-layered soil modulus during roller compaction. Additional analyses were conducted to observe the proper training size and number of iterations to achieve real-time quality control to be used by site engineers. Furthermore, the influences of the relative modulus ratio, drum length and top layer modulus on the soil surface dynamic displacement are discussed.

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.

Correlated evolution between colour conspicuousness and drum speed in woodpeckers.

Sexual selection drives the evolution of many spectacular animal displays that we see in nature. Yet, how selection combines and elaborates different signal traits remains unclear. Here, we investigate this issue by testing for correlated evolution between head plumage colour and drumming behaviour in woodpeckers. These signals function in the context of mate choice and male–male competition, and they may appear to a receiver as a single multimodal display. We test for such correlations in males of 132 species using phylogenetic linear models, while considering the effect of habitat. We find that the plumage chromatic contrast is positively correlated with the speed of the drum, supporting the idea that species evolving more conspicuous plumage on their head also evolve faster drum displays. By contrast, we do not find evidence of correlated evolution between drum speed and head colour diversity, size of the head's red patch, or extent of the plumage achromatic contrast. Drum length was not correlated with any of the plumage coloration metrics. Lastly, we find no evidence that habitat acts as a strong selective force driving the evolution of head coloration or drumming elaboration. Coevolution between different signal modalities is therefore complex, and probably depends on the display components in question.

Woodpecker drum evolution: An analysis of covariation in elements of a multicomponent acoustic display among and within species.

Multicomponent signals are found throughout the animal kingdom, but how these elaborate displays evolve and diversify is still unclear. Here, we explore the evolution of the woodpecker drum display. Two components of this territorial sexually selected signal, drum speed and drum length, are used by territory holders to assess the threat level of an intruding drummer. We explore the coevolution of these display components both among and within species. Among species, we find evidence for strong coevolution of drum speed and length. Within species, we find that drum speed and length vary largely independent of each other. However, in some species, there is evidence of covariation in certain portions of the drum length distribution. The observed differences in component covariation at the macro- and microevolutionary scales highlight the importance of studying signal structure both among and within species. In all cases of covariation at both evolutionary scales, the relationship between drum speed and length is positive, indicating mutual elaboration of display components and not a performance trade-off.

Particle mixing and segregation behaviors in the rotating drums with adjacent axial segmentations in different speed directions

The axial mixing and segregation behavior of particles with different properties is a complicated movement process, whose mechanism is still indistinct. Consequently, it is very important to explore dynamic repose angle and flow characteristics of the particles along the axial direction during the mixing and segregation process. Focusing on the mixing and segregation phenomenon in the rotary drum, this paper studies the particle mixing and segregation behavior by changing the speed direction of adjacent axial segmentations. The results show that alternating axial segregation band characteristics can be formed in adjacent axial segmentations with same velocity direction, while the overall mixing degree is better under the condition of the opposite velocity direction. Although the different rotational speed directions of adjacent axial segmentations will cause opposite axial mixing and segregation phenomenon, the general rules of the dynamic angle of repose and axial flow velocity are similar in the rotary drum. In addition, the axial flow structure of the binary particles varies with rotational speed direction of the adjacent axial segments, but not with the drum length to diameter (L / D) ratio and particle filling rate.

The effect of side walls on particles mixing in rotating drums

In this paper, we study the effects of the presence and shape of side walls and of the overall length of rotating cylindrical drums on the mixing of particles with differing sizes by application of the discrete element method (DEM). By varying the semi-axis of the spheroidally shaped side walls and the length of the overall drum, we observe the formation of circulation patterns near the side walls. Although there is a vast amount of literature studying mixing regimes in rotating drums, little is known about the effect of the side walls of the drum on particle mixing. The results of our study demonstrate that introducing curved side walls induces a strong circulation pattern near these side walls, but has, paradoxically, a negative impact on mixing and actually promotes segregation. The cause for this segregation is the difference in velocity of differently sized particles near the curved side walls. Large particles accumulate at the curved side walls, whereas small particles move away from the curved side walls. When the length of the drum is increased, the overall effect of the side walls is decreased, although it does remain observable, even in very large drums.

Comparative study of hatchability rate and egg quality between different strains of Japanese Quail (Coturnix japonica)

The objectives of this study were to determine morphology of Japanese quail strains andhatchability rate and egg quality between commercial strain which is Poultry Progress Institute(IKTA) strain and White Texas strains of Japanese Quail (Coturnix japonica) rear in Malaysia. Atotal of 300 quails were randomly picked and the breastbone length, chest girth, body weight,body length, shank length and drum length were measured for the morphology. Then, 270 eggs ofCommercial and White Texas strains were used to test the hatchability rate (n=150) and eggquality (n=120). The ratio of the parents of the quails between male and female of each type ofstrain were 1:3. The cleanliness, shape, weight, and texture of the eggshell were observed,weighed and measured. The eggs were incubated for 17 days (37.6 °C, 65% humidity). The shapeindex, egg weight, egg volume and eggshell surface were weighed and measured for the exteriortrait of eggs. For interior trait, the albumen index, Haugh units, and internal quality units (IQU)were measured. Significant findings were observed in all of the features (P<0.05), except for thewing length in morphology. For hatchability rate, there was a high significant in the percentage ofhatchability of incubated eggs, hatchability of fertile eggs and smoothness texture of the eggshell.In egg quality there was high significant in Haugh unit but low significant internal quality unit.The significant variability might be due from the genetic information that inherited from theparents. The IKTA and White strains were not the same in morphology, hatchability rate andinterior trait of eggs but same exterior trait of eggs. In conclusion, this research is important ingiving information about Japanese quail strain in Malaysia and more genetic study should be donein the future to determine good strain and increase understanding about quail strain.

Cataracting-centrifuging transition investigation using nonspherical and spherical particles in a rotary drum through CFD simulations

This paper aims to systematically investigate the cataracting-centrifuging transition in a rotary drum involving spherical and nonspherical particles by using the Multiphase Granular Eulerian Model (MGEM). The effects of drum length and particle shape on the cataracting-centrifuging transition behavior were analyzed. The results showed that drum length plays an important role in the cataracting-centrifuging transition, although most related works in the literature do not consider this. The particle shape also significantly affects the cataracting-centrifuging transition behavior. Nonspherical particles required lower rotation speeds than spherical particles to reach the centrifuging condition. The particle shape was shown to be related to the critical solid fraction (αsc) from Schaeffer’s model, although further investigations are required to completely correlate particle spherecity with critical solid volume fractions.

Research on surface segregation and overall segregation of particles in a rotating drum based on stacked image

At present, image recognition methods have been widely used in the research on measuring particle mixing and segregation in rotating drums. However, currently commonly used methods tend to study mixing and segregation from the perspective of the radial surface of the particles, but rarely from the perspective of the axial surface. Whether the data obtained from the particle surface (radial segregation or axial segregation) can reflect the degree of mixing and segregation of the entire particle system (overall segregation) is still a question worth studying. In this work, an image analysis method based on stacked images to measure the degree of surface segregation is proposed. The drum length to diameter ratio (L/D) and particle filling rate are used as operating parameters. And the discrete element method (DEM) verified by experiments has studied the difference between the surface segregation and the overall segregation of the binary particle groups (different particle sizes) in the rotating drum. This paper compares the qualitative characteristics (particle segregation characteristic patterns) and quantitative characteristics (particle segregation degree) of surface and overall mixing and segregation in detail. The results show that for short drums, radial segregation index can be used to quantify the overall degree of segregation. While for long drums, axial segregation index can be used to quantify the overall degree of segregation.

Analysis of frequency and mode shape of rotating-flexible disk-drum coupled structure with non-continuous connections

This study focuses on the coupling vibration of a rotating-flexible disk-drum structure with a non-continuous connection, and investigates the frequencies and mode shapes of the coupled system. The Sanders’ shell and the Kirchhoff plate theories were considered for the flexible drum and flexible disk, respectively. Artificial springs were utilized to represent the general boundary and non-continuous connection conditions. The rotating speed was also considered for the coupled structure to establish the dynamic equation. First, the proposed model was validated by comparing the results with those obtained from literature and using ANSYS. Next, numerical simulations were performed to determine the effect of the connection point number, rotating speed, connection stiffness, drum length, and disk thickness on the frequency and mode shape of the coupled structure in the static and rotating state. The results show that the frequency increases as the point number increases. When the point number is less than 16, the local deformation of the mode shape is obvious. The analysis of frequency curves, mode shapes, and MAC indicates that the essence of frequency veering, merging, and bifurcation is the vibration coupling and mode shape interaction between the coupling modes. The frequencies increase monotonically with the increased connection stiffness. The axial connection stiffness and disk thickness have a significant effect on the disk-dominant mode. The circumferential and radial connection stiffness and the drum length mainly affect the drum-dominant mode. Compared with other stiffnesses, the rotational connection stiffness has a smaller effect on the frequency of the coupled structure. In a rotating state, with a larger drum length or disk thickness, the frequency veering occurs at a lower rotating speed, while the frequency merging occurs at a higher rotating speed.

Numerical study on the flow field and separation efficiency of a rotary drum separator

In this paper, a new device called rotary drum separator consisting of multi-layer channels is introduced in gas–liquid separation. First, the flow field, including the distributions of pressure and gas velocity at different gas inlet velocities and rotational speeds, is numerically studied. Then, the influences of the inlet velocity, rotational speed, channel shape and size on separation efficiency are discussed by the discrete phase model. The results show that the inlet velocity and rotational speed play a critical role in pressure distributions. Besides, the tangential velocity is linear with the radial position. In triangular channels, the separation performance is better than that in circular and square channels when droplets are larger than 4 μm, and it can be improved by decreasing the radial height or increasing the drum length. Nevertheless, for fine droplets smaller than 4 μm, the separation efficiency is almost independent of the channel shape and size. Additionally, decreasing the inlet velocity or improving the rotational speed is beneficial to increase the efficiency, and improving the rotational speed can also greatly reduce the cut-off diameter.

Rotational stiffness of drum deployed thin-walled open tubular booms

Abstract Tape springs are a type of thin-walled deployable boom that are used extensively in the space industry to deploy sensors, drag sails and antennas. When a tape spring is stowed it coils into a cylindrical shape and so deployment drums are manufactured as cylinders to match. The consequence of this is that when the tape spring is deployed a portion of the cross section remains flat against the cylindrical drum. This has the effect of reducing the stiffness of the tape spring. In this paper a Finite Element (FE) model is presented to capture this reduction. An experimental method for validating the FE model is also presented on which Beryullium-Copper (BeCu) and glass fibre polypropylene (PP) composite tape springs were tested. The FE model is able to predict the rotational stiffness of the BeCu tape springs more accurately than the composite tape springs. The disagreement in the case of the composite tape springs is attributed to inaccuracies in the available data for the mechanical properties, and the assumption that the tape spring does not compress through the thickness. Increasing the drum length has been shown to decrease the rotational stiffness due to increased flattening at the root. BeCu tape springs show an increase of 82% in the rotational stiffness when the flattened drum region reduces from 90% to 30% of the tape springs’ width. Glass fibre PP tape springs with a layup of [ ± 34 ∘ f/0°/ ± 34 ∘ f] show an increase of 65% when the drum length percentage reduces from 82% to 27%. A parametric study showed that the rotational stiffness can be significantly improved with the introduction of local root reinforcing plies.

Flow dynamics of binary mixtures of non-spherical particles in the rolling-regime rotating drum

The flow characteristics of binary mixtures of cylindrical particles in the rotating drum are numerically studied by extending the DEM model developed for spherical particles to non-spherical ones. The flow patterns of the binary mixtures of cylindrical particles are similar to that of spherical ones. Enlarging the length ratio obviously increases the dynamic angle of repose throughout the drum length, which gives rise to greater total kinetic energy and corresponding fluctuation magnitude. The length difference of the constituents leads to radial segregation, with small and large cylindrical particles in the radial core and periphery, respectively. Moreover, radial segregation decreases and increases the mass of large and small particles, respectively, in the active region. Also, enlarging the length ratio clearly increases the streamwise velocity in the active region. Different from the translational velocity, the rotating velocity along the axial direction is of the same scale as the transversal ones.

Comparison of graphic expression of dependences of transporter cut profile of threshing-separating unit on the second volume and spike fraction humidity

Introduction. Threshing is a multifactorial process which is affected, in particular, by the feedrate of the crop, the specific weight of the threshed grain and return, separation rates, weediness and moisture of the crop. From this point of view, the issues of optimizing the profile of the transporter cut, which allows for threshing and separation with the least effort, are also relevant. It was also experimentally established that the threshing process is affected by the volume of grain material delivered per second (second feed) and the unit velocity.Materials and Methods. The studies were conducted on a test bench equipped with a threshing-separating device in the form of a single-cavity hyperboloid. When performing the work, the width of the drum was divided into three zones, and the length – into five cells. Wheat grain, obtained through threshing and separation in each zone and cell, came to individual containers. Straw was collected separately. Then, the grain and straw were weighed. The resulting data was processed by statistical and mathematical methods.Research Results. The lengths of each cell were calculated based on the ratio of the total separation and the amount of grain mass per unit length. The lengths of each cell were calculated depending on changes in humidity. Indicators of the ratio between mass humidity and cell length are presented in the form of a table. By the given table values for different moisture levels of the grain mass, graphs were constructed, each of which was described by a mathematical model considering the drum length and width. An averaged cut profile is presented for the treated plant mass with humidity of 8%, 12%, 16%, 20%, and 24%.Discussion and Conclusions. Analysis of the data in this paper and earlier ones provides the comparison of the graphic expression of the dependences of the transporter cut profile on the second volume and humidity of the grain mass entering it. It has been established that the cut profile curves are identical along the entire length of the drum. The confidence factor is close to 1, which indicates the accuracy of the model. The identity of the averaged cut profiles is obviously dependent on moisture of the plant mass and on the second feed.

Simulation of the granular flow of cylindrical particles in the rotating drum

This study aims at unveiling the effect of particle shape on granular flow behavior. Discrete element method is used to simulate cylindrical particles with different aspect ratios in the rotating drum operating in the rolling regime. The results demonstrate that the cylindrical particles exhibit similar general flow patterns as the spherical particles. As the aspect ratio of the cylindrical particles increases, the active‐passive interfaces become steeper, and the number fraction, solid residence time, and collision force in the active region decreases. The mechanism underlying the difference is the preferential orientation, with particles of greater aspect ratios increasingly orientating their longitudinal axes perpendicular to the drum length. Also, particle alignment in the active region is more uniform than that in the passive region. The results obtained in this work provide new insights regarding the impact of particle shape on granular flow in the rotating drum. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3835–3848, 2018