Experimental study of the driving resistance of a harrow with screw working bodies

The article presents the construction and manufacturing of working screw harrow bodies, as well as the developed experimental setup for experimental studies, presents the methodology of research to determine the traction resistance of the working body. The variations of traction resistance force Px from the speed of harrow movement V, at different values of the angle of attack β of working screw bodies and working depth h are plotted.

Numerical simulation of heat transfer and hydrodynamics under transverse flow of compact bundles of tubes in shell-and-tube heat exchangers

Mathematical Modeling, Vol. 7 (2023), Issue 1, pg(s) 27-29

By using the application package ANSYS Fluent, the numerical simulation of heat and mass transfer processes in the channels of shell-and-tube heat exchanger with compact placement of tube bundles has been carried out. The fields of velocities, temperatures and pressures in the heat exchanger channel were obtained and the conditions of hydrodynamic flow in the channels and the processes of heat transfer in these channels were analyzed. A new construction of shell-and-tube heat exchanger with compact arrangement of tubes in tube bundles is proposed and developed.

Theory of vertical oscillations of a frontally mounted tops harvesting machine

To establish influence of kinematic and constructive parameters of tops-harvesting machine on quality of a continuous cut of the massif of tops at oscillations in the longitudinal-vertical plane of its tops-cutting device at frontally mounted machine on a wheeled row-crop aggregate tractor. Used modeling methods based on higher mathematics, theoretical mechanics, solving a system of differential equations and compiling programs and numerical solutions on a PC. An equivalent scheme has been developed for a tops-harvester mounted on a wheeled tractor in front of it on its oscillations in the longitudinal-vertical plane, considering all the forces that arise, taking into account the kinematic excitation that occurs when moving along soil surface definitions also due to the elastic-damping properties of its support-copying wheels. For the specified equivalent scheme, on the basis of application of initial equations in the form of Lagrange of the 2nd kind, on the chosen generalized coordinates, the system of two nonlinear differential equations of oscillatory motion of the tops-harvesting machine is received. According to the analytical transformations, the solution of this system was obtained, which made it possible to obtain the f inal expressions for determining the amplitude and circular frequency of natural and forced oscillations of the tops-harvesting machine. Numerical calculations of the received expressions on the made program on the personal computer are carried out . According to the results of numerical simulation, the final expression was obtained, which allowed to determine the vertical displacements of the end of the rotary cutting unit during the oscillations of the topping machine in the longitudinal-vertical plane. Numerical calculations on the PC of the received expression gave the chance to construct graphic dependences which establish dependences of amplitude of the specified oscillations depending on constructive parameters of the tops-harvesting machine, and also characteristics of roughnesses of a soil surface and elasticdamping properties of copying wheels.

Mathematical model of root head cleaning machine with vertical drive shaft

The operation of the machine attached to the back of the tractor to clean the heads of root crops from residues in the case of using copying pneumatic wheels causes oscillations of the tops harvester in the vertical plane, which significantly affects the quality of the process. Accordingly, the movement of the horizontal working body will depend on many structural and kinematic factors. Therefore, the development of a mathematical model that will describe the movement of the working body of such a unit is an important task. To solve which the method of construction of calculated mathematical models of functioning of agricultural machines and machine units, on the basis of theoretical mechanics and higher mathematics was used in the work.. Using which the equivalent scheme of movement of the unit is developed and the system of two nonlinear differential equations for detailed research of oscillations of the cleaner of heads of root crops in the longitudinalvertical plane at movement of its pneumatic copying wheels on roughnesses of a surface of soil is received. The mathematical model of movement of the cleaner with a horizontal cleaning shaft developed on the basis of initial equations of dynamics in the form of Lagrange of the 2nd kind allowed to establish depedencies between constructive and kinematic parameters of the car and its oscillatory characteristics. The found dependences created preconditions for the further mathematical modeling of parameters of the rear-mounted cleaner of heads of root crops, with a horizontal clearing shaft. Using the developed calculation model it is possible to optimize the values of angle B and coordinates у that characterize the oscillations of the machine in the longitudinal-vertical plane.

Investigation of the power interaction of the ploughshare digger working body with the soil and sugar beet root for the conditions of its vibratory digging

the basic principles of the theory of interaction of the vibrating digging working body with the body of the root crop fixed in the soil at vibrating digging of sugar beets are developed. The force interaction of ploughshare diggers with the soil is considered in the work. The values of normal soil reactions acting on the ploughshare of the excavating working body are determined, which, when vibrating in the longitudinal-vertical plane, can dig out the bodies of sugar beet roots from the soil. Based on the obtained equations describing this process, the prerequisites for finding the kinematic and structural parameters of the excavating working body are developed.

Construction of a new calculation mathematical model of the vibration process of excavation of the root body from the soil, taking into account its elastic damping properties

The equation of shock interaction of the vibrating digging working body with the body of the sugar beet root, fixed in the soil, which occurs in the process of vibratory digging of the roots, is made. Based on the shock interaction equation, the shock pulse and the maximum shock force that occur during this interaction were determined, which allowed to further assess the degree of damage and knocking out of root heads in the process of vibration digging of sugar beet. From the conditions of non-damage of root crops the expression for definition of admissible frequency of fluctuations of the vibrating digging working body taking into account its design parameters and translational speed of movement of the beet harvester is received. Based on the obtained equations describing this process, the optimal values of the kinematic and structural parameters of the working plow for vibration digging of sugar beets are found.

Experimental research of agricultural bridge unit in the state of harrow aggregate

From the standpoint of energy saving, the issue of research of agro-bridge units in the composition of new agricultural lands adapted to them is important and relevant tools that operate on the principles of track and bridge farming. One of the latter is a heavy tooth harrow with flat segments. Experimental determination of the characteristics of the agronomic bridge harrowing unit in its composition, in order to establish compliance of its parameters with the basic principles of the effective implementation of track and bridge farming, was adopted as a research objective. Experimental research was carried out both according to generally accepted and developed methods, and provided for the use of modern strain gauge and control equipment with analog-digital conversion of signals from information sensors. The processing of experimental data was carried out on a PC using probability theory, regression, and correlation-spectral analysis. Physical objects of researches were wide-track agricultural bridge construction vehicle TDATU with its track width of 3.5 m and harrowing machine (BZSS-1.0 type). According to the results of experimental tests of agricultural bridge harrowing unit as part of the dental harrow proved its good adaptability to work in the units of track and bridge farming and high quality of the technological process. The latter is also a consequence of the fact that the movement of the agricultural bridge is carried out on the compacted traces of a constant tramline, whose roughness profile is low-frequency in comparison with the longitudinal profile of the harrower. The constructive version of the tooth harrow is well reflected in the nature of its unevenness in traction resistance. It is established that the fluctuations of the harrow’s traction resistance express a random function in which there are no harmonic components. The coefficient of variation of resistance fluctuations on the hook of the agricultural bridge during harrowing is no more than 10%. The latter indicates a high stability (low variability) of the process of harrowing the soil, has a positive impact on the stable movement of the agricultural bridge unit.

Substantiation of the process of deep tillage with agricultural machines of digging type

The paper considers the issue of deep tillage, the use of the latest technical advances, in order to develop new tillage implements that provide better tillage and reduce erosion. The main attention is paid to the preservation of soil fertility and the use of funds in organic farming. The aim of the work is to improve the process of mechanical tillage by digging by developing a new working body and the process of interaction of digging working bodies with the soil, which change its physical properties and improve environmental safety. The most promising for deep tillage is the digger in terms of both energy and agronomic indicators (reduction of compaction, preservation and restoration of water and air balance, preservation of humus, preservation of biomass). Rotary diggers with rotational movement of working bodies are more effective in comparison with diggers having oscillating movement of working bodies. As a result of studying the dependence of the angle of the blades, providing the movement of the formation on the surface of the working body, from their position on the trajectory, it was found that the smallest value (5…70) is the angle of inclination after turning the blade deepening. When lifting the formation from the bottom of the furrow to a certain height, the required angle of the blades increases, reaching a value of 28… 300 when overturning the formation at a height of 0.20…0.25 m

Study of specialized wide-rail agriculture unit for rail farming

A promising direction for further sustainable development of agriculture not only in Ukraine but also in the world is the introduction of innovative technologies, which should include the track and bridge systems of agriculture. These systems provide the basis for the automation and robotization of most crop production processes, ensure efficient implementation of “precision” and “digital” farming and provide other significant benefits. Scientists have not sufficiently studied the issue in this regard, and there is currently no effective methodology for implementing the potential technical-operational and technological properties of specialized broad gauge means of agricultural production mechanization for the rutting system of agriculture. Therefore, from the point of view of solving the food problem in the world, especially during the COVID-19 pandemic, as well as developing resource-saving technologies based on the principles of the rutting system of agriculture, in accordance with the trends of scientific and technological progress in the field of mechanization – improving the level of functioning of technical means through integrated mechanization, electrification, automation and robotization – this direction of research is relevant. The aim of the research is to substantiate the main advantages and effectiveness of the use of a specialized vehicle for rutting agriculture by justifying its main parameters. As a result of these studies, it was found that the energy saturation level of specialized agricultural vehicles moving in the tracks of a permanent technological track should be 23.5 kW·t−1, in realizing the traction force at the level of 6.37 kN by 1t of their weight. Losses of the field area for the engineering zone when using agricultural equipment with a wheelbase width exceeding 6 m are 5-6%. The economic effect of the use of broad-wheeled agents in wheat cultivation technology is at least 150 € per hectare.

Assessment of negative impact of agricultural mobile energy means and euro-5 standard

Environmental problems today are one of the most important and global indicators of human development. One of the consequences of the impact of agricultural machinery on natural resources is their pollution due to loss of fuel and lubricants and engine waste. The purpose of the research is to develop scientific and methodological bases for the selection of criteria for assessing the environmental safety of the diesel engine of an energy vehicle with the creation of an environmental safety management system. The scientific and methodological basis for assessing these factors is a systematic approach to solving environmental problems that arise during the operation of machine-tractor units and other agricultural energy resources. Estimation of the level of emissions of the main pollutants and toxic substances in exhaust gases can be defined by means of the regulatory characteristic of the engine depending on an operating mode of this engine. The optimal mode of operation of the engine YaMZ-236M2, from an environmental point of view, adopted 1450…1850 rpm. In this case, fuel consumption does not increase in this mode. It is possible to reduce the emissions of the most significant NOx exhaust element by limiting the engine speed to 90% of the nominal. CO and CH emissions at a given engine speed have not reached their maximum value.

Justification of kinematic parameters of coupling for wide-span row-crop unit

Effective use of the KhTZ-160 tractor is possible, with the specified width, combining the implementation of the main technological process with an additional, i.e. sowing with cultivation. Shows the results of calculations of the transverse displacements of the working bodies as a function of their placement along the width of unit and along its length relative to the transverse geometric axis that passes through the kinematic the center of the tractor without taking into account the curvature of the trajectory of tractor and possible changes in the position of kinematic center along the unit. The largest values of the transverse displacements of the working bodies, which are placed at a distance of 2.6 m, i.e. at the machine which is attached to the rear hinged system of the tractor, reach 14.5 cm at maximum angles of rotation of the unit (3 degrees). The smallest transverse movements of the working bodies are observed when placed on a geometric axis that passes through the axis of the rear wheels (less than 1 cm). The lateral movements of working bodies of 18-row wide-coverage row-crop unit depending on the tractor turning angle and their placement in the unit are considered. Kinematic parameters and coupling scheme are recommended.