Sirvi Autor "Holovach, I." järgi

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Agrophysical condition of chernozem as a criterion for its readiness for soil tillage minimization
(Estonian University of Life Sciences, 2025) Ihnatiev, Yevhen; Bulgakov, V.; Demydenko, O.; Holovach, I.; Trokhaniak, O.; Rucins, A.; Olt, Jüri; Estonian University of Life Sciences. Institute of Forestry and Engineering
The objective of this study was to develop an agrophysical criterion for assessing the condition of leached chernozem under systematic shallow tillage for six years, using differential porosity, crop productivity, and energy efficiency as indicators. The results were compared to those obtained under conventional ploughing, with the goal of evaluating the feasibility of further tillage minimization in a short-rotation grain crop rotation system. The study employed standard research methods, including field observations, laboratory analysis, mathematical statistics, and comparative-calculative approaches. Under shallow tillage, the median bulk density in the 0–30 cm soil layer was higher by 0.03 g cm–3 compared to ploughing, while the standardized density range remained similar across tillage systems. However, both the upper and lower typical values increased by 0.02 g cm–3 under shallow tillage. The coefficient of variation for bulk density was 1.85 times higher under ploughing than under shallow tillage. Differential porosity measurements across five crops in the sixth year of the trial revealed that in spring, shallow tillage resulted in higher bulk density (by 0.06 g cm–3), lower total porosity (by 3%), and a 6.0% reduction in air-filled pore volume compared to ploughing. At the same time, the ratio of waterfilled to air-filled pores approached an optimal 1:1 balance under shallow tillage, whereas ploughed soils showed a dominance of air-filled pores. Systematic use of both ploughing and conservation-oriented shallow tillage over five years in a five-field grain-row crop rotation produced similar levels of productivity in terms of yield, energy efficiency, and output of grain and feed units. While productivity indicators under ploughing remained stable relative to the mean, shallow tillage demonstrated a positive trend. This trend is associated with the completion 1513 of the transition period following the cessation of deep ploughing and the shift toward preliminary deep chisel tillage, followed by systematic shallow tillage at a depth of 10–12 cm.
Assessment of the structural-aggregate composition of podzolized chernozem under various agrogenic impacts and post-agrogenic state
(Estonian University of Life Sciences, 2024) Bulgakov, V.; Gadzalo, I.; Kropivnyi, V.; Demydenko, O.; Holovach, I.; Ihnatiev, Ye.; Trokhaniak, O.; Olt, Jüri; Estonian University of Life Sciences. Institute of Forestry and Engineering
Identify the main patterns of transformation and establish normative parameters of changes in the structural and aggregate composition of low-humus podzolized chernozem (type of soil, known as ‘chernozem’ in Ukrainian, which translates to ‘black soil’) in the Central ForestSteppe of Ukraine in the transition period to the no-till system and minimal tillage in the agrocenosis of 5-field grain generally accepted approaches to assessing soil structure and modern statistical methods of compiling information analysis data. The generally accepted research methods were used: field, laboratory, mathematical methods, comparative and computational. The study uses fractal comparative analysis, which is a sensitive tool for assessing the distribution of structural units and water-stable aggregates in the soil. Over the past 6 years, the experimental plots have been organized with a 5-field grain-row crop rotation using three different primary tillage systems: systematic plowing, surface tillage, and transitional tillage (minimal tillage on the background of systematic plowing six years ago). It was found that the structural-aggregate state of the 0–30 cm layer of Chernozem under surface tillage was in better condition in terms of aggregate water stability over the seasonal cycle and provided better conditions for further transition to the no-till system in crop rotation compared to surface tillage after systematic plowing. According to fractal indicators, the state of water-resistant structure in the spring is assessed as unstable, although the surface treatment of qualitative and quantitative indicators of water resistance is better compared to plowing. In the summer, a fractal assessment of the state of the waterproof structure showed that regardless of the method of tillage, its condition has deteriorated to a greater extent. Thus, the fractal dimension was at the level of D > 2, which indicates the edge of the unstable state of the waterproof structure, but the Hurst index was H ≤ 0, which indicates the process of destruction of waterproof aggregates. Based on the definitions, we can say that from the systematic application of surface tillage agrophysical condition of 0–30 cm layer of chernozem in terms of structural condition and water resistance of the structure was in better condition compared to plowing and transitional tillage, which should be regarded as the end of the transition period (6 years) before the application of the No-till system in unchanged design in 5-field crop rotation.
Development and examination of high-performance fluidised bed vibration drier for processing food production waste
(2020) Kaletnik, H.; Sevostianov, I.; Bulgakov, V.; Holovach, I.; Melnik, V.; Ihnatiev, Ye.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
Drying and processing wet particulate food production waste, such as distillery dreg, brewer's grains, beet pulp, spent coffee and barley slurry etc. for their further use as cattle fodder or fuel is an important and topical problem, which needs effective solutions. As a solution of the problem, the authors have developed improved equipment and a fluidised bed vibration drier, which ensures reaching the required output of the work process and final moisture content in the waste at a minimum power and material intensity and features the combination of the high feasibility with the high reliability of design. In order to validate the improved drying work process together with the optimum parameters of the vibration drier, theoretical investigations based on the mathematical model of the process developed by the authors have been carried out. The process of the vibration drier’s frame oscillating together with the waste has been examined, which has resulted in the generation of the differential equation that analytically describes the said process. The work process under consideration has been researched into from the thermophysical point of view using the specific initial data typical for the specific food producer. The research has resulted in obtaining the following design and process parameters of the vibration drier, in particular, for its heating pipes: diameter rt = 0.1 m; length lt = 5 m; number nt = 20, heat-transfer factor Kp = 30 and the final temperature of the dried food production waste to2 = 80 °C. The listed parameters provide for reaching the required final moisture content in the dried food production waste. Also, new relations have been generated for determining the principal process parameters of the improved drier (productive capacity, heat consumption, mass of heat carrier, waste conveyance speed, sizes and masses of the drier’s actuating elements). The obtained relations can be applied in the further theoretical and experimental research on the drier as well as the development of standard methods for its design and calculation.
Justification of parameters for novel rotary potato harvesting machine
(2021) Bulgakov, V.; Bonchik, V.; Holovach, I.; Fedosiy, I.; Volskiy, V.; Melnik, V.; Ihnatiev, Ye.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
The authors have set an aim in relation to the development of a novel rotary potato harvesting machine design and the substantiation of rational design and process parameters for the clod crushing tools in the machine in order to improve its separation capacity. A novel design solution has been suggested for the process of crushing the two adjacent potato rows with the vanes of the vertical rotor and the expediency of using the methods of crushing clods in the two adjacent potato rows in advance has been justified. Also, the more rational placement of the clod crushing tools in the potato harvesting machine has been suggested. Following the completed research, the geometrical parameters of the vertical rotor have been substantiated, in particular, its diameter dр = 0.65–1.0 m and height hzag = 0.27 m. Additionally, the process parameters have been substantiated for some other tools crushing the clods, in particular, the angle of inclination of the share’s working face, which has to be equal to 10°, the elevator belt width bel = 1.05 m, the linear velocity of the belt Vp = 1.95 m s –1 , the belt agitation amplitude Аst = 18 mm. If the soil moisture content is equal to W = 18.4%, the soil separation rate rises insignificantly, when the rotor diameter increases within the range of 0.65–1.0 m, moreover, at Vm = 1.0 m s –1 it varies within the range of 85.3–87.2%, at Vm = 1.5 m s –1 – within the range of 87.0–92.7%, at Vm = 2.0 m s –1 – within the range of 86.0–89.1%. The best performance is achieved at a rotor rotation frequency of nр = 100 min–1 and a translational velocity of Vm = 1.5 m s –1 , in which case the soil separation rate S is equal to 93.5%. The tuber damage rate Pb decreases from 4.2% to 1.5%, as the rotor diameter dр increases from 0.65 m to 1.0 m, the translational velocity of the machine Vm – from 0.8 to 2.2 m s –1 at the rotor rotation frequency nр = 50–100 min–1.
Mathematical model of cleaning potatoes on surface of spiral separator
(2018) Bulgakov, V.; Nikolaenko, S.; Arak, Margus; Holovach, I.; Ruzhуlo, Z.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
Cleaning potato tubers from soil impurities and plant debris after digging them out of soil is a topical problem in the work process of potato production. Therefore, the engineer ing of new designs of potato heap separators necessitates the further studying of them and the optimisation of their kinematic and design parameters, which must not only ensure the high quality of cleaning, but also rule out the possibility of damaging the tubers. The aim of this study is to determine the design and kinematic parameters of the improved design of the spiral potato separator, which will ensure the high quality of cleaning and rule out the possibility of damaging the tubers, on the basis of th e development of the new theory of potato tuber’s motion on the surface of the separator. An analytical study has been carried out resulting in the construction of the equivalent schematic model of the interaction between the potato tuber and separator, th e tuber being approximated by a material point on the surface formed by the two cantilevered spirals, which are the separator’s tools. The separator’s spirals are driven to rotate and at the same time they can perform oscillations in the vertical and axial plane under the action of the varying load generated by the continuous feeding of the potato heap for separation. In the model, the forces acting on the potato tuber’s body are applied to it, the coordinate axes that have been selected and appropriately o riented are shown. A system of equations has been set up for the constructed equivalent schematic model, comprising three differential equations of the potato tuber body’s motion on the surface of the trough formed by the two cantilevered spirals. The dete rmined kinematic and design parameters will allow to raise the quality of cleaning potato tubers from soil impurities and plant debris. .
Motion stability estimation for modular traction vehicle-based combined unit
(2020) Bulgakov, V.; Holovach, I.; Nadykto, V.; Parakhin, O.; Kaletnik, H.; Shymko, L.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
One of the promising ways of efficiently applying high power intensity tractors is their design and utilisation in the form of modular traction vehicles comprising two modules: the power module and the process module. In order to provide for the sufficient manoeuvrability of the modular traction vehicle, when its process module passes a turn, the latter is equipped with vertical and horizontal hinge joints. The freedom of the process module’s rotation with respect to the power module in the horizontal plane through the agency of the above-mentioned vertical hinge joint is restrained by a hydraulic cylinder, in which the chambers above and below the piston are connected via a throttle valve with a hydraulic resistance coefficient of about 1.03×106 N m s rad–1 . This paper is concerned with the theoretical and experimental research into the stability of motion (on turn spaces as well as in the transport mode) of a modular combined unit, when its velocity changes and/or the slip resistance coefficient of the tyres on the wheels of the process module, in which the hydraulic cylinder is equipped with a throttle valve with the above-mentioned hydraulic resistance coefficient, changes.
Numerical modelling of process of cleaning potatoes in spiral separator
(2019) Bulgakov, V.; Nikolaenko, S.; Holovach, I.; Adamchuk, V.; Ruzhуlo, Z.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
Cleaning potato tubers from soil and plant residues after their digging from the soil is a topical problem in the industrial production of potatoes. Taking into account the fact that the cleaning spirals are positioned with overlapping and rotate in the same sense, the potato tuber that has landed on the surface of the spiral separator in the trough between two adjacent spirals will perform translational motion towards the output ends of the spirals. As a result of solving the said system of equations, the graphical relations between the values of the normal reactions and friction forces generated during the translation of the potato tuber along the mentioned spirals, on the one hand, and the design and kinematic parameters, on the other hand, based on the requirement of not damaging tubers when performing the said work process of transportation and cleaning, have been obtained. The limitations for the normal reactions and friction forces at the points of contact between the tuber and the surface of the cleaning spiral are set in accordance with the requirement that they do not exceed the force of scraping (damaging) the tuber’s external surface permissible for potato tubers. That has provided an opportunity to obtain the rational values of the design and kinematic parameters of the separator’s operating spirals, in particular, the value of the angular velocity of the rotating cleaning spirals as well as their radius and helix lead.
Research and justification of parameters for a flexible sectional screw working body
(Estonian University of Life Sciences, 2025) Bulgakov, V.; Olt, Jüri; Ihnatiev, Yevhen; Holovach, I.; Trokhanyak, O.; Estonian University of Life Sciences. Institute of Forestry and Engineering
The article presents a new design of the hinged-sectional working body of a flexible screw conveyor intended for transporting bulk agricultural materials. The influence of the hinge mechanism’s structural parameters on its operational efficiency is investigated, particularly in terms of ensuring the required angular displacement of axes, preventing jamming, and minimizing energy losses. Analytical dependencies are proposed to determine the arc displacement of the ball along friction surfaces, its velocity, and the efficiency coefficient of the hinge mechanism. It is established that the maximum efficiency coefficient ranges between 0.88 and 0.91 when the ratio of the ball radius to the rotation radius of ball centers is within 0.3–0.45. Calculations show that an increase in the conical socket inclination angle leads to a reduction in efficiency. To enhance the overall conveyor efficiency, it is recommended to reduce the hinge axis deviation angle, which results in a larger bending radius of the screw. Specifically, it is determined that the axis deviation angle should not exceed 20–25° while maintaining an efficiency coefficient of at least 0.9. To determine the optimal structural characteristics of the screw working body sections, computer modeling of force load influence on corresponding deformations was conducted. The results show that an increase in torque leads to a greater twisting angle of the section, with the most significant deformation occurring at a minimal number of axial rods. The proposed design improves the efficiency of loading and unloading operations while expanding technological capabilities in transporting grain and other bulk materials.
Research into geometric parameters of digging shares used for lifting sugar beet roots from soil with assistance of vibration
(2021) Bulgakov, V.; Holovach, I.; Adamchuk, V.; Ivanovs, S.; Melnik, V.; Ihnatiev, Ye.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
One of the important conditions in securing the high quality, when performing the work process of vibrational root lifting, is to avoid damaging the roots. It is obvious that the greatest probability of damaging and even breaking the lifted root arises, when the tool interacts with the root body during their first contact and in the time of the root passing in the throat between the operating shares. The aim of the study is to substantiate the rational design length for the working throat of the vibrational root lifter in its interaction with the sugar beet root while lifting the latter from the soil. As a result of the completed research, the minimum permissible tool oscillation frequencies have been determined for the specific values of the lifter’s translational velocity and the working throat rear part length, at which the event of the vibrational lifting tool gripping the root will occur at least one time. For example, when the length of the lifter’s working throat rear part is equal to 0.1 m and the oscillation frequency is equal to ν = 20.3 Hz, the satisfactory quality of the vibrational root lifting process is ensured, when the velocity of the translational motion performed by the vibrational lifter stays within the range of 1.3–2.55 m s –1 . In order to ensure the good quality of the vibrational root lifting process at the lifter’s translational velocity equal to V = 2.0 m s –1 and the frequency of its tool’s oscillations equal to ν = 10 Hz, it is necessary that the length of the lifter’s working throat rear part is equal to 0.2 m, at a tool oscillation frequency of 6.7 Hz - 0.3 m. As a result of the completed numerical calculations, the permissible values have been determined for the tool oscillation frequency, which can be recommended for the translational velocities within the range of 1.3–2.2 m s –1 , taking into account the limitation set for the tool oscillation frequency by the pre-condition of the guaranteed gripping of each root by the digging shares.
Seasonal sequestration capacity of chernozem under different agrotechnological impacts in agrocenosis
(Estonian University of Life Sciences, 2024) Bulgakov, V.; Gadzalo, I.; Pascuzzi, S.; Demydenko, O.; Holovach, I.; Ihnatiev, Ye.; Olt, Jüri; Estonian University of Life Sciences. Institute of Forestry and Engineering
The soil's sequestration capacity is primarily determined by the fine-dispersed fraction of the soil and strongly influences the properties and fertility level of the soil. To assess the sequestration capacity of C-CO2 humus in soil formation and fertility of typical chornozem (black soil), to identify the causes, rates, existing limits of the sequestration capacity decrease, it is important to study the seasonal dynamics of qualitative and quantitative indicators of humus state in time depending on the method of tillage and fertilization in agrocenoses of short rotation crop rotations in the central part of the Forest-Steppe region of Ukraine. During the research, a stationary field experiment was conducted to study the influence of methods of soil cultivation and fertilizer application on the sequestering capacity of chornozem. Laboratory studies were conducted to determine the content of humus and to calculate the seasonal reserves of absorbed carbon and phosphorus and to model the absorption capacity of chernozem. When processing with chisel plows and applying fertilizers, the increase in the C-CO2 reserve during the April-July period was +21 t ha-1 (0–0.2 m) and +36 t ha-1 a (0–0.3 m). Under moldboard plowing, the growth tended to increase by 1.52 times (0–0.2 m) and 1.25 times (0–0.3 m), but occurred at a lower quantitative level, and in the period July-September, the change in the humus C-CO2 stock was insignificant, indicating the predominance of C-CO2 sequestration processes in the summerautumn period with chisel plowing. With chisel plowing, the reserve of labile organic substances (LOS) in April exceeded the stock for plowing in the thickness of 0–0.3 m by 4.34–7.67 times (without fertilizers), 1.5–2.76 times (with fertilizers); in July - by 4.59–8.90 times (without fertilizers) and 1.32–3.16 times (with fertilizers); in September - by 4.52–4.04 times (without fertilizers) and by 1.11–1.93 times (with fertilizers), and the C-CO2 stock of the LOS compared to fallow land under chisel plowing without fertilizers in April, July, and September was 1.59–1.78 times, 2.31–3.29 times, and 1.4–1.78 times higher, and under fertilization - by 1.99–2.0, 1.86–4.50, and 1.7–2.6 times, respectively, depending on the seasons. Under fallow land maintenance, the seasonal dynamics of the C-CO2 stock of the LOS is subject to the seasonal dynamics of Porg(LOS). A direct strong correlation was found at the level of R = +0.89 ± 0.02; R2 = 79. In the period April-July, the decrease of Porg(LOS) stock in the thickness of 0–0.2 m was found to be 1.15 times, and in the thickness of 0–0.3 m - 1.1 times. From summer to autumn, the stock of Porg(LOS) was restored, and the stock in the thickness of 0–0.3 m increased by 1.10 times. Conclusions. Trends in C-CO2 stocks of humus and LOS indicate that in the series plowingchiseling-fallow land, the cyclicality index under chisel plowing was closer to the value of the seasonal cyclicality of fallow land than the seasonal cyclicality under plowing, which indicates the restoration of the CI. Trends in C-CO2 stocks of humus and LOS indicate that in the series plowing-chiseling-fallow, the index of cyclicality under chisel plowing was closer to the value of the seasonal cyclicality of fallow land than the seasonal cyclicality of plowing, which indicates the restoration of the ISC. However, the timing of changes in the Porg(LOS) stock indicates that in the series plowing-chiseling-fallow, chisel plowing is directed to fallow land by its seasonal cyclicality. The general regularity of seasonal cyclicality for all parameters of humus condition lies in the fact that a decrease in the values of ISC, as in fallow land or under moldboardless tillage, indicates the ordering of ISC, and an increase in the index of cyclicality to destruction, as under plowing.
Structural-aggregate condition and utilization of productive water reserve depending on the tillage method of podzolized chernozem in agrocenosis
(Estonian University of Life Sciences, 2024) Bulgakov, V.; Gadzalo, I.; Chernovol, M.; Demydenko, O.; Holovach, I.; Ihnatiev, Ye.; Trokhaniak, O.; Mitkov, V.; Olt, Jüri; Estonian University of Life Sciences. Institute of Forestry and Engineering
The work established the features of formation of the structural-aggregate condition and determine the main patterns of the formation of spring productive water reserves and its consumption in a five-field crop rotation when cultivating winter wheat and spring cereal crops using different tillage methods (plowing, systematic surface tillage, No-till systems based on plowing and systematic surface tillage) of podzolized chernozem (black soil) in the conditions of the central part of the Forest-Steppe of Ukraine. Common research methods were applied: field, laboratory, mathematical, and comparative-computational. Analysis of the results showed that during surface treatment, water-resistant aggregates are enlarged into the most valuable fraction, which affects the more rational use of productive water reserves during the growth of crops in crop rotation. Under the No-till system (in years 2–3), there is an accumulation of productive moisture in the soil layer of 0–1 m by 8–12 mm more compared to conventional tillage, and relative to the water reserves in 2022, the water reserve in 2023 increased by +19.0 mm (after conventional tillage) and by +14.0 mm (under surface tillage). Under the no-till system, in June and July, the average productive water reserve for the years 2022–2023 was higher compared to conventional tillage by 5–10 mm and 7–10 mm, respectively, and compared to surface tillage by 10–12 mm and 18–21 mm, respectively. In 2023, the productive water reserve in July under the No-till system exceeded that under conventional tillage by 17 mm, and compared to surface tillage by 31 mm. This improvement in soil structure water resistance in June and July was due to the increase in the content of water-stable aggregates sized 3–0.5 mm.
Theoretical and experimental research into impact of threshing tools in combine grain harvesters on quality of cereal crop seeds
(2020) Derevjanko, D.; Holovach, I.; Bulgakov, V.; Kuvachev, V.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
The theoretical and experimental research into the micro-damaging of cereal crop seeds in the process of their harvesting by combine grain harvesters in relation to the strains, forces and stresses imparted to them by the threshing tools has been carried out. The propagation of deformations and cracks in the seeds as well as the nature of their strength and the damage that is sustained, when the critical load is applied, have been investigated. It has been established that the onset of cracks, the direction of their propagation and their quantity in the bodies of grain seeds depends in the majority of cases on the direction of action of the external forces and the specifics of the seeds’ internal biological properties. It has been established that the strength of the grain seed is, apart from the arisen cracks, also under the significant effect of the microtraumas in the germ, endosperm as well as the seed coat and shell. Theoretical calculations have been carried out on the PC and the effect that the drum and rotor threshing apparatus have on the deformation and damage sustained by cereal crop seeds has been substantiated. The said calculations and the obtained graphic relations support the results of the experimental investigations and prove that the macro- and especially micro-damage sustained by the seeds of winter wheat and rye is different, when they are threshed with the use of different types of threshing apparatus, which has a considerable impact on the final quality of the harvested cereal crop seeds. The results obtained in the experimental investigations, field and laboratory tests on the topic of the effect of mechanical loading on the sustained damage and quality of seeds indicate that the damage rate accounted for the work processes of the reaping and postharvest treatment of the cereal crop heaps of different winter wheat varieties with the use of rotor threshing apparatus is 3.1% as compared to the drum threshing apparatus – 6.4%, that is, 2 times lower. The total amount of the seeds with microtraumas collected in the hopper after threshing amounts to 23.0% and 54.0%, respectively, which is a significant difference. Similar results have been obtained in the experimental investigations on the effect of the equipment on the sustained damage and quality of seeds in the cleaning, chemical treatment and sowing of cereal crops.
Theoretical study on forced transverse oscillations of root in soil with provision for soil’s elastic and damping properties
(2020) Bulgakov, V.; Holovach, I.; Ruzhylo, Z.; Melnik, V.; Ihnatiev, Ye.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
The topic of the paper is the theory of the forced transverse oscillations performed by the root fixed in the soil under the action of the harmonic perturbing force vectored at right angle to the root’s centreline and along the line of the translational motion performed by the lifter. On the basis of applying the Ostrogradsky-Hamilton variational principle and using the equivalent schematic model developed by the authors, the expressions have been obtained that allow to determine the amplitude of the forced transverse root body oscillations as function of the perturbing force amplitude value as well as the soil’s elastic deformation and damping coefficients. The ranges of the elastic soil deformation coefficient values, at which the resonant behaviour is observed, that is, at which the forced elastic root body oscillation amplitude value exceeds the tolerance limits, have been determined for the 10, 15 and 20 Hz frequencies of the perturbing force produced by the vibrational lifting tool. That said, the mentioned oscillation amplitude values can vary from 0.58 to 0.45 m, which is sufficient to result in the root breaking. Moreover, it has been proved that, with the increase of the perturbing force frequency, the resonant behaviour ranges shift towards the increased values of the elastic soil deformation coefficient. Therefore, such elastic soil deformation coefficient ranges should be avoided in case of the lifting tool design proposed in the paper. As regards the damping properties of the soil, it has been proved that they do not cause any resonance phenomena.
Theory of grain mixture particle motion during aspiration separation
(2020) Bulgakov, V.; Nikolaenko, S.; Holovach, I.; Adamchuk, V.; Kiurchev, S.; Ivanovs, S.; Olt, Jüri; Estonian University of Life Sciences
The practice of separating grain mixtures with the use of the difference in the aerodynamic properties of their components has proved that the process of separating mixtures in the aspiration separator is the most promising one with regard to the improvement of quality and intensification of production. The authors have developed a new improved design of aspiration seed separators, in which the work process of separating seed material is performed with the use of vibration processes. In this seed material separator, the constant force air flow that acts on the sail members on the central pipe of the separator, when seeds are fed for processing, generates self-excited oscillations in the pipe, which produces centrifugal forces of inertia in the seed feeding system. As a result of the mentioned effect, the propelling force in the process under study substantially increases, accelerating the seeds of different fractions, which differ in their masses, to different velocities. The motion paths of the seed particles change accordingly, heavier particles moving closer to the vertical axis of the aspiration channel, which provides for increasing the efficiency of separation of the seeds of different fractions from each other. In this paper, a new mathematical model is developed for the motion of a seed mixture material particle in the operating space of the separator’s aspiration channel. The mathematical modelling of the process of vibration and aspiration separation has indicated that the separation of the motion paths of the medium and heavy fractions takes place within the range of 20–40 mm; the flying speed of the particles is equal to 3.2–8.0 m s–1, respectively; and their acceleration is equal to 1.8– 3.3 m s–2, which provides the necessary conditions for the accurate and high quality separation into the required fractions. In view of the found differences between the kinematic characteristics of the separated fractions of the grain mixture, the diameter of the pipeline for the medium fraction is to be within the range of 90–100 mm, for the heavy fraction – 50–70 mm.
Theory of motion of grain mixture particle in the process of aspiration separation
(2020) Bulgakov, V.; Nikolaenko, S.; Holovach, I.; Boris, A.; Kiurchev, S.; Ihnatiev, Ye.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
The paper describes the development of a mathematical model for the motion of a seed mixture particle in the aspiration channel of the separator after the particle passes the cone-shaped spreader and enters the workspace of the aspiration channel in the pneumatic dynamics and vibration unit devised by the authors. The unique feature of the proposed new design is the presence of the central pipe with sail members in the aspiration channel. The sail members in the air stream generate the self-oscillatory mode of motion of the central pipe, which results in the efficient separation of the grain seed mixture into the required fractions. On the basis of the prepared equivalent schematic model, the differential equations of the motion of a seed mixture particle in the process of aspiration separation have been generated. Basing on the results of the PC-assisted numerical modelling of the motion paths, on which the material particles (seeds) of the heavy and medium fractions travel, it has been established that they move on different courses, and the course of the heavy fraction seeds is such that, after they pass the cone-shaped spreader and advance further in the air stream through the space of the aspiration channel, they move closer to the pipe of the aspiration channel. Also, their velocities and accelerations are greater than the same kinematic parameters of the medium fraction seeds. The seeds of the light fraction move upwards under the action of the air stream and leave the aspiration separator at its top.
Theory of oscillations performed by tools in spiral potato separator
(2020) Bulgakov, V.; Holovach, I.; Ruzhylo, Z.; Fedosiy, I.; Ihnatiev, Ye.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
The aim of this study is to provide for the intensification of the process of removing impurities from the potato heap by oscillating devices, which takes place, when potato tubers are cleaned in the spiral separator during their lifting. The authors have devised a new design of the spiral separator, which can be used in the process of lifting potatoes from the soil. It comprises cantilever cleaning spiral springs, which in their simultaneously rotary and oscillatory motion clean and transport the potato tubers with good quality. However, the removal of impurities from the cleaning area and the cleaning of the side surfaces of potato tuber bodies from the stuck soil can be significantly more effective, if the spiral springs perform their oscillatory motions in the longitudinal and vertical plane during their operation more intensively. In order to achieve that, the authors have worked out a new theory of the oscillatory motion of the cleaning spiral working under the action of the potato heap. That promotes the intensification of the process of cleaning potato bodies from the stuck soil. The authors have generated a new partial differential equation, which describes the oscillations of the cantilever cleaning spiral. The PC-assisted numerical solving of the said differential equation and further numerical modelling have made it possible to obtain the analytic expressions of the relations between the change in the helix pitch distance of the cleaning spiral and its deformation, in particular, the simultaneous longitudinal extension and transverse bending. That result, in its turn, provided for finding the maximum limit amount of the above-mentioned deformation under the condition that the potato tubers may not fall through the spaces between the spiral turns, taking into account the design and kinematic parameters of the cleaning spiral itself, the material it is made of and the process-dependent mode of operation of the separator. As a result of the PC-assisted numerical modelling, it has been found that the total deflection of the spiral on its length varies within the range of 0 to 0.05 m under the following parameters: angular velocity of rotation of the spiral ω = 30 rad s-1, density of the material of the spiral ρ = 7,700 kg m-3, elastic modulus Е = 2∙1011 Pa, cleaning spiral bar stock radius r = 8.5 mm and a uniform load intensity of 1000 N m-1. Such variation ensures the good quality of cleaning and transportation of potato tubers. According to the results of the PC-assisted numerical calculations, the helix pitch distance of a cleaning spiral with the above parameters and the original helix pitch distance S = 48 mm, due to the spiral’s deformation under the proposed transverse oscillations, can change up to 54 mm, which makes impossible for potato tubers to fall out of the cleaning unit. Experimental studies fully support the results from the theoretical calculations to determine the displacement of the ends of the cleaning unit’s spiral springs.
The theory of vibrational wave movement in drying grain mixture
(2020) Bulgakov, V.; Holovach, I.; Kiurchev, S.; Pascuzzi, S.; Arak, Margus; Santoro, F.; Anifantis, A.S.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
This paper outlines a theory that involves the vibrational wave transportation of bulk grain during the course of passing that grain under an infrared radiation source, in a working thermal radiation drying chamber, and using a vibrational wave transporter belt that has been developed by the authors of this paper. The main outstanding feature of the proposed design is the presence of mechanical off-centre vibration drives which generate the vibration in the working rollers at a preset amplitude and frequency, thereby generating a mechanical wave on the surface of the flexible transporter belt which ensures the movement of bulk grain along the processing zone which itself is being subjected to infrared radiation. A calculation method was developed for the oscillation system that is used in conjunction with the vibrational transportation of the grain mass, in order to be able to determine the forces that may be present in the vibrational system and to prepare the differential calculations for the movement of the vibrational drive’s actuators, utilising for this purpose Type II Lagrange equations. The solving of the aforementioned integral equations on a PC yielded a number of graphical dependencies in terms of kinetic and dynamic parameters for the vibrational system described above; the analysis of those dependencies provided a rational structural, along with kinetic and dynamic indicators. According to the results that were taken from theoretical and experimental studies on the functioning of the developed infrared grain dryer combined with a vibrational exciter, stable movement for its working roller takes place if the angular velocity of a drive shaft is changed within the range of between 50–80 rads–1 , whereas the amplitude of the indicated oscillations falls within the range of 3.0–4.0 mm. It has been discovered that a rational speed when transporting soy seeds during infrared drying falls between the range of between 0.15–0.60 cm s -1 , whereas the amplitude of the indicated oscillations falls within the range of 3.0–4.0 mm. An increase of this parameter within the stated limits increases the time that it takes to achieve the stage in which a constant drying soy speed is reached by more than 2.5 times (from 205 seconds to 520 seconds), stabilising the figure at a level of 520 seconds, which makes it possible to recommend a range of transport speeds of between 0.15–0.40 cm s –1 under infrared radiation for the seeds in order to achieve the required moisture content with a single pass of the produce on the wave transporter. With that in mind, the power consumption levels for the vibrational exciter do not exceed 50W, while the angular velocity of the drive shaft’s rotation falls within the range of between 100– 120 rads–1 . The results of the experimental study that has been conducted indicated that a rational transportation speed for the soy seeds on the wave transporter under infrared radiation is between 0.15–0.40 cm s –1.

Sirvi Autor "Holovach, I." järgi

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