Rational Operating Modes Research Articles

Scientific and practical basis of cephalopods dehydration processes

Nowadays, it is relevant to solve the problems of adapting optimal resource- and energy-efficient modes to technologies for processing food raw materials. The work is focused on the analysis of the prerequisites to find similar features in the dehydration of food capillary-porous colloidal materials by means of various methods. The authors have studied the patterns of cephalopods dehydration using the example of octopus and squid under different heat treatment regimes. It has been proved that there is only one critical point characterizing the transition from moisture with a lower binding energy to moisture with a higher one, and an equation has been proposed for finding the critical humidity during dehydration of the objects been studied. A generalized mathematical model has been developed to determine the duration of the process at the current moisture content of the food material based on dimensionless similarity criteria characterizing the phenomena been investigated. The dependences of the moisture removal rate for different heat treatment methods of cephalopods are given according to their initial moisture content, the specific surface area of the material and the operating factors that determine the process. The obtained dependencies and patterns open up unique opportunities for labor-saving design in the food industry using rational operating modes of industrial enterprises, optimization of heat treatment processes in general and the creation of energy-efficient equipment new designs.

Model of the non-stationary thermal processes in the ground heat pump system

One of the main directions for improving heat supply systems is the tendency to switch to low-temperature heating systems by using heat pump units is the tendency of implementation the low-temperature heating systems based on the use of heat pump units. In the work, the main attention is focused on the improvement of thermal parameters and circuit design features of elements of the heat pump system of heat supply using soil energy. For this purpose, the toolkit of mathematical modelling of processes in ground heat pumps is applied, taking into account the climatic conditions of Ukraine. The paper proves the technical possibility of creating an autonomous system of alternative heat supply for energy-saving technologies with the possibility of using ground energy, taking into account environmental requirements. It is substantiated that the use of the proposed systems is a promising direction for Ukraine, which is experiencing a shortage of its own energy resources, because it provides an opportunity to increase the share of organic fuel substitution and reduce the volume of heat emissions into the environment. A mathematical model of heat processes in the elements of the heat exchange equipment of the heat pump system based on renewable energy (soil energy) and secondary energy (wastewater) was developed, taking into account environmental requirements (preventing hypothermia of the soil during the operation of soil pipes and damage to vegetation, respectively), which allows choosing a rational mode of operation of the system under seasonal climatic changes and technological conditions. Numerical modelling of heat processes in elements of the heat exchange equipment of the heat pump system using groundwater and waste water was performed, and the energy and environmental efficiency of the system under variable climatic and technological factors was determined. Analysis and generalization of the calculation results of the heat pump heat supply systems using alternative energy based on the proposed mathematical model, taking into account environmental requirements (preventing thermal relaxation of the soil) allows to take into account the change in the temperature gradient around the soil heat exchanger and more accurately determine the heat flow from each section of the heat exchanger. It has been established that for heat pumps with soil heat exchangers, the maximum substitution ratio of the traditional fuel is 75 %, and the economically feasible quantity of soil heat exchangers is 9 units. Heat pumps using waste water can completely replace traditional heat supply systems. For individual consumers, it is possible to recommend heat pump units with soil heat exchangers, at the same time, it is necessary to provide a backup source of energy to increase the reliability of heat supply.

Operation of downhole pumps under sanding conditions

One of the unfavourable factors of downhole pumping equipment operation at the fields at the final stage of development is high content of mechanical impurities in the pumped fluid. Similar problems are observed in fields with friable, weakly cemented formations, the fracture products of which flow downhole, resulting in lower extraction rates, equipment damage and higher operating costs. In oil production practice various technological measures and technical means are used to reduce the negative impact of sand penetration - regulation and optimisation of pumping equipment operation mode to ensure a rational rate of fluid withdrawal, application of technical devices in the form of sand filters and sand anchors and others. However, these measures and recommendations, for the most part, work successfully in the modes of continuous operation of wells. With the growing number of oil fields at the final stage of development, the issue of sanding becomes more and more urgent, as due to low flow rate wells at such fields are often switched to the mode of periodic operation, which favours the formation of sand plugs in tubing above the pump due to sufficient time for sedimentation of mechanical impurities. This can lead to pump jamming or rod breakage during subsequent well pump start-up. The experience of using sand filters (frame, slotted and others) in the arrangement of downhole pumps has shown that it does not always effectively solve the problem of sand penetration due to clogging of their cells with mechanical impurities and increased hydraulic resistance. This negatively affects the pumping equipment operation due to the shift of characteristics into the zone of suboptimal modes with associated problems for the electric drive. This makes it necessary to carry out underground well workover with removal of deep well pumping equipment for replacement or washing of the filter in surface conditions, as due to their peculiarities in the well pump layout (the filter is located at the intake of the pumping section), washing in well conditions is not always possible. These problems require not only the creation of effective downhole devices to prevent sand ingress to the pump intake or devices to prevent sand plugs above it, but also acceptable in practice calculation methods for predicting the sedimentation time of mechanical impurities in tubing or determining the minimum required speed of upward oil flow for stable sand removal. These calculation methods would also allow to reasonably regulate the time of technological interruptions while waiting for the wells to start up in periodic operation modes or to predict the time of activation of sand control devices for discharging the sand accumulated above the pump. This is the subject of this article. As a result of calculation analysis it was established that the main factors affecting the sedimentation process of mechanical impurities in the well are the speed and mode of fluid movement, its viscosity, density and size of the impurities themselves. Moreover, the most sensitive for the calculation accuracy is to take into account the change of fluid viscosity as it moves along the tubing as a result of heat exchange and the change of dissolved gas content due to pressure drop. Although at this stage the proposed methodology does not take into account some factors that can make additional adjustments to the process of sand sedimentation, however, it allows to predict with acceptable accuracy the time of technological interruptions in the well operation to prevent the formation of sand plugs, or the rational mode of operation of pumping equipment, providing the necessary speed of upward flow in the pipe for sand removal.

Study of the probabilistic and temporal characteristics of wireless networks using the CSMA/CA access method

Objectives. The aim of this study is to develop analytical methods to evaluate the probabilistic and temporal characteristics and performance of wireless networks using the CSMA/CA access method. These methods enable the process of selecting rational operating modes to be automated and the impact of collisions in networks implementing the 802.11 protocols to be reduced.Methods. The methods employed herein include reliability theory, theory of random processes, queuing theory, and the Laplace–Stieltjes transform.Results. A problem statement is presented and developed, along with an analytical method for evaluating the probabilistic and temporal characteristics and performance of wireless networks using the CSMA/CA access method. This method considers time constraints on information transmission, thus expanding the applicability of previously proposed analytical approaches for studying Ethernet local area networks. The analysis of networks that use the CSMA/CA access method was carried out. An original mathematical model was developed that allows evaluating various characteristics of packet transmission processes in wireless networks under time constraints on the transmission. These characteristics include latency, packet transfer time, node load, and network performance. A software package was developed to simplify the analysis and evaluation of various operation modes of wireless networks using the CSMA/CA access method.Conclusions. We demonstrate the need for developing nested analytical models describing packet transmission processes in wireless networks under time constraints on link-layer transmission. This implies the development of more complex models for more exact description of packet transmission processes in such networks. The software package developed herein enables the various options for the functioning of the network to be studied and analytical calculations to be performed. Calculations were carried out, in order to assess the probabilistic and temporal characteristics of packet transmission processes and the wireless network performance. The research involved varying the number of workstations and the intensity of packet flows entering the network nodes under the time constraint on packet transmission. The application of the developed mathematical models will be useful in creating and optimizing wireless networks such as Wi-Fi networks, networks based on the IEEE 802.11 standard, and other data transmission systems using the CSMA/CA access method. Such models and the analysis based on them will be useful in optimizing network performance, adjusting parameters, as well as selecting the capacity and configuration of wireless networks.

МАТЕМАТИЧЕСКОЕ ОПИСАНИЕ ДИНАМИКИ ЦЕНТРОБЕЖНОГО ДВУХФАЗНОГО ПОТОКА В ПОМОЛЬНОЙ КАМЕРЕ ДЕЗИНТЕГРАТОРА

Rational control of equipment operating modes in the production of building materials is possible only in the case of a mathematical description of various technological processes. The sequence of calculation methods for determining the design and technological parameters of grinding equipment makes it possible to numerically present the results of calculations of rational operating modes of the equipment. The study presents a mathematical description of the dynamics of a two-phase flow inside the grinding chamber of a disintegrator, with the help of which it is possible to determine the speed characteristics of its operating modes for materials with different physical and mechanical properties. The nature of the change in the tangential components of the velocities of the two-phase flow has been established: the range of the current radius of the grinding chamber Ri has been determined, at which the radial components of the velocities of the carrier flow and particles of the ground material continue to increase. As a result of mathematical modeling, it was confirmed that with an increase in the concentration of dust particles in the increasing volume of the grinding chamber, the value of the tangential component of the velocity of a dynamic two-phase flow decreases in relation to the maximum parameters at Ri = 0.15 m by an average of 15.5%. It has been determined that the maximum velocity values for the tangential component are in the limit of Ri = 0.1-0.15 m and are 131 m/s for air, and 127.5 m/s for an average suspended particle with dsr = 40 μm. In the process of developing a mathematical description, it was established that in the range Ri = 0.15 - 0.3 m the increase in the radial components of the velocities of the air carrier medium and the weighted average particle flow is about 14.5%, which, in turn, indicates an increase in the kinetic energy of the crushed particles during the movement of a dynamic two-phase flow from the center to the periphery of the grinding chamber of the disintegrator.

ОЦЕНКА ЭФФЕКТИВНОСТИ ПОДАВЛЕНИЯ АММИАКА В ВОЗДУШНЫХ СРЕДАХ ПРОИЗВОДСТВЕННЫХ ПОМЕЩЕНИЙ С ИСПОЛЬЗОВАНИЕМ БАРЬЕРНОГО РАЗРЯДА

One of the main problems in the industrial production of livestock and poultry products is the neutralization of toxic gases in the air removed from livestock premises. Ozonation is used for this. Ozone is produced in dielectric barrier discharge installations. The disadvantages of the method include the dependence of the electrical characteristics of the dielectric barrier discharge on the parameters of the medium and the generation of nitrogen oxides. (Research purpose) The research purpose is determining the effectiveness of ammonia suppression by ozone generated in dielectric barrier discharge installations at various parameters of the generator operating mode. (Materials and methods) Established the effectiveness of ammonia suppression by ozone at various parameters of the ozone generator operation mode. A 25 percent aqueous solution of ammonia with controlled purging over the surface of the solution was used as an ammonia source. The dependences of the mass concentration of ozone (O3), nitrogen oxides (NOx) and hydrogen sulfide (H2S) at the generator output on the operating mode parameters were studied. It was shown that the range of changes in the concentration of gases varied within the following limits: ozone - from 180 to 4, ammonia - from 80 to 2, hydrogen sulfide - from 4 to 0, nitrogen oxides - from 0 to 130 milligrams per cubic meter. (Results and discussion) It was found that the concentration of ammonia decreased from 50 to 10 milligrams per cubic meter; the time to reach the specified values of the concentration of ammonia in the stream was 20-50 seconds; when ozone is generated in all operating modes, nitrogen oxides are formed in the weight ratio O3/NOx from 1.42/1 to 1/1. The dependences of the generation of ozone and nitrogen oxides on the input voltage of the generator power supply unit were determined. It was noted that the optimal pumping rate of plasma-forming gas (atmospheric air) ranged from 0.8 to 1.5 m/ s; the mass ratio of nitrogen oxides to ozone varies from 0.69 to 0.98, which is unacceptable for premises with permanent residence of animals and maintenance personnel. (Conclusions) It was stated that the results obtained in assessing the rational operating modes of ozonators allow us to formulate technical requirements for the development of a specialized ozone generator adapted for use in agricultural production.

РЕЗУЛЬТАТЫ ЭКСПЕРИМЕНТАЛЬНЫХ ИССЛЕДОВАНИЙ ПЛУГА-РЫХЛИТЕЛЯ В АГРЕГАТЕ С ТРАКТОРОМ ТЯГОВОГО КЛАССА 5

The results of experimental studies of the machine-tractor unit (MTA), consisting of a tractor of traction class 5 K-744R and a mounted plow-ripper PBS-16 presented in the article. Determining the performance of the plow-ripper in the experiments was provided by changing the translational speed of the machine-tractor unit. Fuel consumption was recorded from the moment the unit entered the test plot at a steady speed and the unit left it. Experimental studies of the work of the MTA were carried out in the field conditions of the Marxovsky district of the Saratov region. Agrotechnical indicators were determined during the processing of fields on the stubble of chickpeas and millet. It has been established that the plow-ripper can be aggregated with tractors of traction class 5. The rational mode of operation of the plow with a working width of 6 m is ensured at a speed of 7.2-9.0 km/h and a working depth of 35 and 25 cm. unit operation was 3.6-4.5 ha/h, fuel consumption was 12.9-11.7 kg/ha. The unit provides a high degree of soil crumbling with a moisture content of 17-20% with the safety of stubble and plant residues on the agrobackground of millet up to 78%, on the agrobackground of chickpea up to 42%. Loosening the arable horizon up to 35 cm with mulching of the surface layer creates optimal conditions for the accumulation of moisture in the autumn-winter period. The movement of the MTA in the corral by the shuttle method, without the formation of dump and breakup furrows, provides a flat, ridgeless surface of arable land.

Математическая модель процесса движения частиц рудного материала по виброоргану сепаратора

Introduction. One of the vibration methods for processing loose finely dispersed mineral raw materials is the separation method on a vibrating surface. Separation occurs according to size, shape of particles, coefficient of friction, elasticity and other mechanical parameters of particles. The efficiency of the separation process depends on the correct choice of technological characteristics of the working equipment. To solve such problems, mechano-rheological models are widely used. The issues of rational construction of research models, based on the specific conditions of the considered dynamic processes, are important and relevant. Materials and methods of research. Identification of rational parameters and modes of operation of vibration equipment is carried out experimentally or by mathematical modeling of the vibration process of the interaction of particles of mineral raw materials with the vibrating body of the separator. Mathematical models are developed for the separated components of the original ore material, which allow studying the dynamics of the movement of particles of the material along the vibrating body of the separator, and as a result of the research, the most rational operating modes of the equipment are determined. Research results and discussion. The presented mechano-rheological system as a model of a material particle is designed to study the processes of interaction with the working body of the separator, a mathematical description of the model is given. The model makes it possible to study the influence of the mechanical properties of the material (elastic, dissipative, plastic) on the dynamics of the process of movement of a material particle along the working body of the separator. For different stages of particle motion, models of different levels of complexity are recommended, which greatly facilitates the solution of problems for the development of algorithms and software for the vibration process under study. This increases the efficiency of the practical application of mathematical models in determining the rational operating modes of the equipment and evaluating the effectiveness of the vibration separation process. Conclusion. To study the process of vibrational separation at various stages of the movement of particles of ore material, it is recommended to use mathematical models of different levels of complexity. A mathematical description of research models for various stages of the vibrational process is presented, the conditions for the transition between the stages of particle motion are given. Resume. Thus, the presented mathematical model makes it possible to study the dynamics of the movement of ore material along the working body of the separator, taking into account the main mechanical properties of the material. The use of the developed recommendations increases the efficiency of the practical application of mechanorheological models for research purposes.

МЕТОДИКА ВЫБОРА РЕЖИМОВ ФУНКЦИОНИРОВАНИЯ ПРИВОДА КАРЕТКИ ЗОНДОВОГО ОБОРУДОВАНИЯ ПРИ ПЕРЕХОДНЫХ ПРОЦЕССАХ. ЧАСТЬ 2

The article presents the results of studies, the analysis of which made it possible to identify features that affect the duration of the main periods of horizontal movement by the carriage drive with the object stage of the probe control equipment, the main of which include the mode of smoothness (dynamics) of movement and the accelerations associated with it during acceleration and braking, provided by the setting of the motor controller, as well as the step of displacement. It is shown that for specific inertia-stiffness and damping characteristics of the probe control equipment, the determination of accelerations for each mode of smoothness and duration of damping of mechanical oscillations after the carriage with the object stage moves to a given coordinate can be carried out in the debug mode of the probe control equipment or automatically using adaptive control. A method is proposed for selecting rational operating modes for the carriage drive with an object stage of probe equipment during transient processes using a database and a displacement step (of crystal size), which makes it possible for each smoothness mode to determine the cyclogram of its displacement and the total duration of the entire cycle, from which the minimum cycle is selected and implemented.

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЙ АЭРОДИНАМИЧЕСКИХ СВОЙСТВ ЗЕРНОВЫХ МАТЕРИАЛОВ

The aerodynamic properties of the components of the grain pile during its post-harvest processing are one of the most important parameters affecting the quality of the resulting grain and seeds. Existing devices are considered that allow establishing the speed of soaring of grain materials, their shortcomings and limitations are noted. A sail pneumatic classifier has been developed that provides smooth adjustment of the air flow rate and high accuracy of its measurement. Experimental studies have been carried out to establish polygons for the distribution of soaring speeds for a number of grain materials using the developed classifier. It has been established that the ranges of soaring speeds for different crops differ significantly. The soaring speed ranges for wheat and bindweed buckwheat do not intersect, which allows them to be completely separated using an air flow at a speed of 5.91-8 m/s. The soaring speed of sorghum (8.37-10.02 m/s) is completely covered by the range of this indicator for wheat, so it is not possible to separate them using aspiration systems. The ranges of critical rates of millet, vetch and wheat partially intersect, which indicates the impossibility of complete separation of these impurity components without loss of grain of the main crop. At an air flow rate of 9 m/s, 96.9% of the impurity component will be released from the wheat-millet grain mixture with technological losses of the main crop at the level of 4%. Even with a slight increase in the air flow rate, a significant increase in wheat losses is inevitable. Vetch can be completely separated from wheat at an air speed of 11 m/s with a loss of 1.8% of wheat. The results of the performed studies are necessary to improve the efficiency of the use of pneumatic separating equipment through the use of reasonable rational operating modes.

Methodological Approach in the Simulation of the Robustness Boundaries of Tribosystems under the Conditions of Boundary Lubrication

In the presented work, a methodical approach was developed for determining rational operation modes of tribosystems, taking into account their design. This approach makes it possible in the designing stage, according to the predicted operating modes, to calculate the limits and margins of stable work in operation. The definition of the robustness of the tribosystem and the criteria for assessing the robustness are formulated based on the theory of stability of technical systems. It is shown that such a methodical approach allows for determining the modes of the rational operation of the designed structures without damaging the friction surfaces. Experimental studies have proven that not all designs of tribosystems lose stability due to the appearance of friction surface burrs. There are designs where the loss of stability occurs upon the appearance of accelerated wear. The developed criteria take into account two options for the loss of stability. An experimental verification of the modes of loss of stability of tribosystems was performed by the appearance of a burr or the beginning of accelerated wear with the calculated values of the robustness criteria. The obtained results allow us to conclude that the modeling error is within 8.3–18.7%, which is a satisfactory result in the study of friction and wear processes. Robustness criteria is based on the coefficient of friction RRf and wear rate RRI, and must be used when designing new constructions of tribosystems. Theoretical calculations of such criteria and the dependence of their change on changing the predicted operating modes will allow for justifying rational operating modes within their stability.

The results of the study of the qualitative parameters of the multifunctional seeding machine

The article presents a constructive scheme of a multifunctional seeding apparatus and substantiates the relevance of its use for agricultural producers of the Southern Federal district with a total area of arable land up to 50-70 hectares. This multifunctional seeding machine allows sowing in various ways for each crop. To assess the qualitative performance of the multifunctional seeding machine in Kuban State University named after I. T. Trubilin, a private methodology and experimental setup were developed at the PriMa department. A mathematical model of the frequency of a single seed supply by a multifunctional seeding machine for sowing corn and wheat has been developed. The parameters for the rational mode of operation of the multifunctional sowing machine for sowing wheat and corn have been determined: the rotation frequency of the disk n, the pressure in the seed chamber P and the frequency of a single seed supply is M for sowing wheat and corn. It was found that the frequency of a single seed supply during wheat sowing is more influenced by the value of excess pressure in the seed chamber. The frequency of a single seed supply during corn sowing is greatly influenced by the value of excess pressure in the seed chamber.

Механизм управления структурой медицинского учреждения как организационной системой массового обслуживания в условиях нестационарного потока

The task of organizing the process of repurposing medical and preventive institutions by managing the bed resource on the basis of coordination of the interests of agents in the non-stationary dynamics of diseases, in particular coronavirus infection, is considered. The relevance of the task is due to the need to make effective management decisions when limiting the temporary resource and the impossibi¬lity of using previously used approaches, in particular statistical data on incidence peaks. The solution is possible through the proposed control mechanism. Aim. The purpose of the work is to develop a mechanism for managing the composition and structure of the organizational system, which allows ensuring the rational behavior of channels with a demanded ratio of performance indicators and quality of service. These measures help to reduce patient queues, reduce the number of unmet patients by providing the necessary and sufficient bed capacity in a timely manner. Materials and methods. It is proposed to use principles of open management of systems with active elements, method of simulation modeling to describe processes of loading of departments of institution with known period of discrete accumulation of applications and process of their processing, as well as mechanism of complex evaluation and generalized median mechanisms of coordination of opinions of agents. This choice is due to the unsteady flow of applications for hospitalization and the need to make management decisions in the organizational system when limiting the temporary resource and bed capacity. These methods will allow agents to quickly make decisions and exclude factors of subjectivism. Results. A subject-oriented model was built in a separate unit using a software product represented by complex evaluation mechanisms. The importance of a comprehensive assessment reflects the significant influence of factors in the search for a rational mode of operation of the department and makes it possible to predict its timely change. The modified median scheme allows you to quickly agree on the true opinions of agents, and the graphoanalytical method in this matter makes the procedure for finding a coordinated solution visual and convenient. Conclusion. The mechanism proposed in the work allows effective management of the composition and structure of the organizational system, thereby improving the work of the medical institution in case of non-stationary processes of receipt of applications for hospitalization.

Some aspects of the processes of obtaining and application of mineral powders as fillers for cement systems

The main theoretical prerequisites for the thermodynamic analysis of the process of grinding rocks are given. The structural-energetic relationships between the regularities of plastic deformation with energy characteristics that occur during the crushing of mineral substances are described. The evaluation of the grindability of rocks in a ball mill under different grinding modes was made. Rational operating modes of the mill have been determined to ensure the required degree of grinding, which makes it possible to significantly reduce the energy consumption of the grinding process. To assess the quantitative content of adsorption centers, a classification of the “indicator of reduced hydration activity” is proposed. (Ppga), allowing the most accurate assessment of the contribution of the surface activity of mineral fillers to the course of the processes of interactions and transformations occurring in a hydrated medium.

Substantiation of research results on energy efficiency of basalt crushing

Purpose. To experimentally determine the main design and operational parameters of the influence of rock mass properties on the Roller Crusher performance when processing basalt rock mass. Methodology. The crushing and grinding of basalts are studied by the methods of mathematical statistics in order to identify the results obtained and determine the dependences of technological parameters on the mechanical impact factors. Experimental studies are carried out on the example of basalts from the Rafalivskyi quarry in the Rivne region. Findings. It has been revealed that the elemental composition of rocks in the benches of basalt quarries has a different mineral composition. Experimental studies of the rock crushing results have determined the efficiency of using screening for crushing basalts. The experimental dependences of the roller crusher performance in crushing and grinding modes on the properties of the rock mass have been obtained. Originality. The value of crushed rock fractal joints has been found, when using cone and centrifugal crushers, which is characterized by the shape factor and fractal dimension D. For cone crusher Kf=2.15.0 and D=1.4. For centrifugal crusher Kf=1.51.8 and D=1.17. These parameters testify to the energy feasibility of using centrifugal crushers. The high value of the multiple correlation coefficients R2 and Fisher criterion F, whose value at a significance level of 0.05 is higher than the critical one, indicates a sufficient convergence between the experimental and theoretical results and the accuracy of the obtained analytical dependences. Practical value. The generalized models for determining the Roller Crusher performance, obtained for each rock type, based on significant factors, greatly facilitate the choice of parameters for crushing and grinding processes, and also allow choosing a rational mode of crusher operation.

Features of Modeling the Operating Modes of Outdoor Lighting Lines

The necessity of modeling the operating modes of outdoor lighting lines with a voltage of 0.23/0.4 kV is substantiated. The choice of the optimal configuration of the lighting line while ensuring the standardized values of illumination and brightness on the working surface is recommended to be carried out by comparing several variants with different positions of pillars, types of light intensity curves, the number and power of luminaires. The results of the lighting calculation are the basis for modeling the electrical operation modes of outdoor lighting lines, which allows determining the operating parameters (node voltage, active and reactive power, current, voltage drop, loss of active and reactive power in individual sections). The obtained data can be used to select the cross-sectional area of conductor cores and forecast the power consumption of outdoor lighting, taking into account the specific features of light flux regulation (dimming). As a rule, outdoor lighting lines are connected to one power point. The use of outdoor lighting lines with bilateral supply for main streets and circular roads of relatively long length is proposed which will not only make it possible to increase the reliability of power supply of lighting installations, but also to use conductors with a smaller cross-section area of the cores. The electrical load of light sources is assumed on the basis of static characteristics. Modeling of the electrical modes of the outdoor lighting network is carried out taking into account the higher harmonics of current and voltage. The rational operation mode of the outdoor lighting line is determined by the magnitude of the voltage deviation from the nominal value, the indicators of non-sinusoidality and voltage asymmetry at the power supply point. Additional possibilities for modeling the modes of operation of lighting lines are to search for damage (detection of short circuits, determination of the presence of faulty lamps).

Study of an Ejector Water Intake and Treatment Plant with a Pressure-Vacuum Hydrocyclone

The intake of natural water or waste water from a depth exceeding the suction height of centrifugal pumps is mainly carried out due to additional water supply at the suction of the pump. However, this process becomes more complicated if it is necessary to purify water from mechanical impurities. The purpose of the presented work is to consider this issue based on the development and study of the parameters of an ejector water intake treatment plant equipped with a pressure-vacuum hydrocyclone. The main contribution of the ongoing research is the establishment of the technological parameters of the installation, and their features in the pressure-vacuum mode of operation, in contrast to the known pressure and vacuum hydrocyclones separately. In terms of methodology, the main parameters of the developed installation were established during the testing of its prototype on a specially built stand using well-known regulatory guidelines in the hydraulic research system. As a result of the study, the nature of the change in pressure inside a cylindrical–conical hydrocyclone, with established design dimensions and the patterns of formation of vacuum and pressure-vacuum modes depending on the initial parameters, was revealed. The data obtained to determine the effect of technological parameters of ejection and the characteristics of the supplied water with impurities on the operating mode of the hydrocyclone confirm the efficiency of water intake and purification. A rational mode of joint operation of the elements of a closed system is achieved at the maximum value of the installation efficiency and ensuring low specific energy consumption per 1 m3 of treated water.

Restoration of the heat exchange surface under conditions of its contamination during condensation of a vapor-gas mixture

THE PURPOSE. Determine the operating mode of a heat exchanger designed to transfer heat from a vapor-gas mixture containing solid particles. Get a dependency for calculating the time after which it is necessary to restore the surface by washing it with water. To carry out estimated calculations of the operating mode of the heat exchanger installed at the PULP Invest enterprise. To increase the stability of the heat exchanger and reduce environmental pollution by cellulose particles.METHODS. In solving this problem, the laws of heat and mass conservation, balance ratios in the calculation of economic costs were used.RESULTS. The article describes the relevance of the topic, discusses the features of the operation of a heat exchanger in which heat is transferred from a condensing vapor-gas mixture containing solid particles. An assumption is made about the mechanism of deposition of these particles on the heat exchange surface. A dependence is obtained that allows us to determine the time after which the surface needs to be restored, taking into account the cost of water and electricity.CONCLUSION. Studies have suggested the mechanism of sediment formation on the heat exchange surface. Choosing a rational mode of operation of the heat exchanger will significantly save water consumption for surface restoration, as well as extract the greatest amount of heat from the steam-gas mixture. The release of particles into the air can be reduced.

О МОДЕЛИРОВАНИИ СЛУЧАЙНЫХ ПРОЦЕССОВ В АГРОПРОМЫШЛЕННОМ КОМПЛЕКСЕ

Research was carried out with the aim of mathematical description of random deviations of the incoming flow of raw materials, to justify the necessary rational modes of operation of continuously operating units in the agro-industrial complex. The incoming flow is given by the average value and random deviations in different directions. The intensity of the deviation from the average value up or down can be different. The numerical characteristics of the incoming stream are determined by processing statistical observations. Two tasks are considered separately. In the first, in order to determine the time or cyclicity of response to changes in the incoming flow, their total number is studied. For this, a pure reproduction model was used. On the basis of the constructed model, the numerical values of the probability that by the time t there will be n deviations are calculated. Such a function Pn(t) has its maximum for any value of n. When solving the second problem, it is assumed that deviations of the average value of the incoming flow in different directions can partially or completely compensate for one another. To take into account such features of a random flow, a model of reproduction and death was used. The calculation of the corresponding probabilities is reduced to solving a system of differential equations, taking into account the normalization condition P0+P1+P2+ … Pn=1. Calculations have shown that if the deflection intensities in different directions are equal, the probability graphs Pn(t) have a common time asymptote. Consequently, deviations with the same intensity, having different signs, compensate for one another. If the intensities are not equal, then the probabilities Pn(t) go to their individual asymptotes. This means that the input stream with random deviations takes its stationary state with some reduced rate. The considered mathematical models make it possible to calculate the probabilistic values of the incoming flow parameters and their changes over time. This makes it possible to justify the necessary rational mode of operation of continuously operating units, taking into account random deviations of the incoming flow

О МОДЕЛИРОВАНИИ СЛУЧАЙНЫХ ПРОЦЕССОВ В АГРОПРОМЫШЛЕННОМ КОМПЛЕКСЕ

Research was carried out with the aim of mathematical description of random deviations of the incoming flow of raw materials, to justify the necessary rational modes of operation of continuously operating units in the agro-industrial complex. The incoming flow is given by the average value and random deviations in different directions. The intensity of the deviation from the average value up or down can be different. The numerical characteristics of the incoming stream are determined by processing statistical observations. Two tasks are considered separately. In the first, in order to determine the time or cyclicity of response to changes in the incoming flow, their total number is studied. For this, a pure reproduction model was used. On the basis of the constructed model, the numerical values of the probability that by the time t there will be n deviations are calculated. Such a function Pn(t) has its maximum for any value of n. When solving the second problem, it is assumed that deviations of the average value of the incoming flow in different directions can partially or completely compensate for one another. To take into account such features of a random flow, a model of reproduction and death was used. The calculation of the corresponding probabilities is reduced to solving a system of differential equations, taking into account the normalization condition P0+P1+P2+ … Pn=1. Calculations have shown that if the deflection intensities in different directions are equal, the probability graphs Pn(t) have a common time asymptote. Consequently, deviations with the same intensity, having different signs, compensate for one another. If the intensities are not equal, then the probabilities Pn(t) go to their individual asymptotes. This means that the input stream with random deviations takes its stationary state with some reduced rate. The considered mathematical models make it possible to calculate the probabilistic values of the incoming flow parameters and their changes over time. This makes it possible to justify the necessary rational mode of operation of continuously operating units, taking into account random deviations of the incoming flow