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Sirvi Autor "Ruzhylo, Z." järgi

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  • Pisipilt
    Kirje
    Experimental research into the effect of harrowing unit’s operating speed on uniformity of cultivation depth during tillage in fallow field
    (2020) Bulgakov, V.; Nadykto, V.; Kaminskiy, V.; Ruzhylo, Z.; Volskyi, V.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
    Retention of soil moisture is an urgent topic of the day in the cultivation of agricultural crops. Using fallow fields is one of the ways to solve the named problem, but the tilling of such fields requires observing some special conditions, in particular, the capillary effects in their upper soil layers must be cut down. For that purpose, the authors have proposed a special harrow equipped with the tools capable of fulfilling the above-mentioned task. The authors have carried out extensive field experiment research into the tillage of fallow soils with the use of the said implement. In order to apply the implement, a new harrow unit has been developed. The results obtained during the experiment research have been processed with the use of statistical methods and it has been established that the depth of harrowing in the tilled field decreases, when the operating speed of the combined unit under consideration increases to 3.3 m s –1 . At the same time, the variances of oscillations of the parameter under research in accordance with the Cochran's C test remain uniform. Also, the frequency of the harrowing depth oscillations changes insignificantly. That is supported by the correlation lengths of the normalized correlation functions of the process under consideration, which, at the above-mentioned operating speed, stay within the sufficiently narrow range of values: 0.16–0.20 m. According to the results of the experimental investigations, the maximum value of the normalized cross-correlation function for the relation between the oscillations of the field harrowing depth and the oscillations of the field’s longitudinal profile does not exceed 0.12. This testifies to the absence of any substantial interrelation between the said two stochastic processes, which is quite reasonable in view of the small values of the variance and period of the oscillations of the field’s longitudinal profile. The probability of the new combined tractor and harrow unit maintaining the tolerance of the fallow field cultivation depth oscillations within the range of ± 1 cm is equal to 82%. Within each 1.85 m of the distance travelled by the combined soil cultivation unit under consideration, only one instance of the field cultivation depth deviating from the ± 1 cm tolerance can be expected.
  • Pisipilt
    Kirje
    Theoretical research into operation of rotary potato harvester
    (2021) Olt, Jüri; Bulgakov, V.; Bonchik, V.; Ruzhylo, Z.; Volskiy, V.; Melnik, V.; Ihnatiev, Ye.; Kaletnik, H.; Estonian University of Life Sciences. Institute of Technology
    The topic of the paper is the determination and justification of the rational design and kinematic parameters of clod breaking tools in rotary potato harvesters with the aim of improving their separating efficiency. A new mathematical model has been developed for the motion of a soil particle on the working surfaces of the cone-shaped and cylindrical vanes in the rotary tool of the new design developed by the authors. Differential equations have been generated for the motion of a soil clod as a material particle from the moment of its arrival to the surface of the vane until the moment of its departure from the said surface. As a result of the completed investigations, relations have been established between the time of contact and absolute displacement of the soil particle and the velocity of its departure from the rotor vane surface, on the one hand, and the kinematic and design parameters of the rotor, on the other hand. For example, when the machine translation velocity increases, the absolute displacement of the soil particle within the interval from the time zero to the moment of its departure from the vane surface increases from 0.59 m to 0.65 m, the velocity of soil particle departure from the vane surface - from 1.61 m s–1 to 1.81 m s–1. The highest values of the absolute displacement of the soil particle and the velocity of its departure from the vane surface are achieved at a machine translation velocity of 2.0 m s–1. The time of the contact between the material particle and the vane surface decreases with the rise of the translation velocity. When the rotor rotation frequency varies within the range from 20 min–1 to 100 min–1, the absolute velocity, with which the soil particle leaves the vane surface, rises to 4 m s–1. The duration of the contact between the material particle and the vane reaches its maximum value of 0.33 s, when the rotor rotation frequency varies within the range of 30–40 min–1.
  • Pisipilt
    Kirje
    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.
  • Pisipilt
    Kirje
    Theoretical study on motion of potato tuber on surface of separator
    (2020) Bulgakov, V.; Nikolaenko, S.; Ruzhylo, Z.; Fedosiy, I.; Nowak, J.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
    The aim of the study was to determine the optimal design and kinematic parameters of the separator that cleans potatoes from impurities and has a design of the spiral type. The authors have devised a highly efficient design of the spiral type potato heap separator, in which the motion of the potato tubers takes place in the channel formed by two spiral members made in the form of cylindrical spiral springs. In order to substantiate the optimal kinematic and design parameters of the new spiral type potato heap separator, the authors have generated a mathematical model of the motion of a single potato tuber on the cleaning surface formed by two spirals. As a result of solving the obtained analytical expressions, the graphical relations between the parameters of the investigated process of the motion of a single potato tuber body situated between two adjacent spirals have been plotted, which has enabled selecting the optimal design and kinematic parameters of the spiral separator. It has been established in the completed investigation that the angular velocity of rotation of the cleaning rolls has to be within the range of 27 40 rad s -1 in order to ensure the efficient transportation and cleaning of the potato tuber with a diameter of 50 mm that moves on the surface of the spiral with a radius of 75 mm wound from the round bar with a diameter of 15 mm, in case the spirals are mounted with an eccentricity of 10 mm. By analysing the kinematics of motion of the potato tuber on the surface of the spiral type cleaning machine, in case the tuber contacts the spirals at two points, it has been established that the increase of the angular velocity of rotation of the spirals results in the respective growth of the transportation capacity of the cleaning tool, while the separating efficiency at the same time becomes reduced to some extent.
  • Pisipilt
    Kirje
    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.