Physical Modeling Method Research Articles

Autoregulatory of water level with flexible working bodies for partition structures on channels

To improve the existing designs of hydraulic automatic gates with flexible working bodies for partition structures on channels, the object of the study was the development and study of an innovative design of an autoregulator of the water level with flexible working bodies. The study's main objective was to create a structure that provides automatic level control, discharge of excess water, washing of deposits in front of the partition, and determining its throughput. The developed design consists of a gate with flexible working bodies and a water level regulator combined with it. The article provides a theoretical formula for determining the flow rate of lateral water flows through the gate of the water level autoregulator. Experimental studies were carried out on an experimental installation by the method of physical modeling using the criterion of geometric similarity of the model and nature. As a result of these studies, simpler formulas were obtained for determining the flow rate of lateral water flows through the gate and a formula for determining the total flow rate of water passing through the gate of the water level autoregulator with flexible working bodies for use during operation.

Разработка энергоэффективного асинхронного электропривода мотор-вентилятора электровоза

For the ventilation system of a traction electric drive of an alternating current electric locomotive, the asynchronous electric drive with high technical and economic indicators has been developed. According to the compiled system of equations for the operation of the asynchronous motor in the rotating coordinate system, a computer model in the SimInTech software package and direct start model are constructed, graphs of transients in current velocity in two modes are obtained. It is proposed to start and regulate the rotational speed of the asynchronous electric motor using a frequency converter and speed feedback control systems. Such a technical solution enables limiting the starting currents within two nominal values. In addition, setting the speed of an electric drive blower motor based on the current temperature of traction engines will reduce the energy consumed by the electric drive and the noise level in a locomotive crew compartment. For solving the tasks assigned in this research paper, the systematic approach, method of physical modeling, provisions of theoretical electrical engineering, numerical modeling on a PC using the SimInTech software package were used.

Specifical features of designing of magneticaly levitated transport systems using permanent magnets

The purpose of the present research is to find approaches for the implementation of constructive solutions that allow for stable suspension and transverse stabilization of magnetolevitation transport systems based on permanent magnets. In order to achieve this goal, the methods of physical modeling were used. Measurements of the magnitude of magnetic induction were carried out using a certified magnetometer Aktakom ATE-8702. While conducting experiments and creating physical models, NdFeB permanent magnets with dimensions of 21x21x21 mm were used. As a result, the suspension and transverse stabilization design based on permanent magnets has been developed and patented. Within the framework of the research, a mock-up of a suspension device for a magnetolevitation transport system was developed and manufactured. The outcomes obtained can be used in the development of technical units with reduced energy consumption, with a minimum coefficient of friction in the guides (escalators, travelators, elevators, etc.), with reduced vibration (magnetic supports) and with minimal consumption of lubricants.

Model studies of a curved suction pipe of pumping units

The purpose of the research was to study the hydraulic conditions of the flow supply in the new design of the curved suction pipe and to study the effect of these conditions on the pump operation. Improving the suction pipes provides a predetermined schedule of water supply, reducing unproductive losses and the cost of electricity for water lifting. Therefore, such studies are relevant. The article uses methods of physical modeling with the introduction of the obtained data on full-scale structures. The values of the dimensionless coefficients and the corresponding hydraulic gradients for various times are studied on a suction pipe model at Qmax and Qmin, over the entire range of operating parameters. The chosen method of improving the suction pipes provides an optimal water supply schedule, reducing unproductive losses and electricity costs for water lifting. During the reconstruction of pumping stations, projects for the modernization of water supply facilities were introduced with annual energy efficiency amounting to 1312 million sum for the pumping stations Kuyumazor, Kiziltepa-1 - 105 million sum.

TECHNICAL SUPPORT FOR THE CULTIVATION OF FRUIT AND BERRY PRODUCTS ON PEBBLE IANDS

The problem of involvement in the economic turnover of pebble lands is considered, taking into account the fact that agricultural technology of agricultural crops on such lands has its own characteristics. A number of elements of crop cultivation and care technology differ from elements of agricultural technology on conventional soils. The main factor determining the need for the use of special technology in these conditions is the high skeletality of soils. The different thickness of the colmatation horizon, its absence in places, as well as the different degree of enrichment of pebble deposits with a fine-grained fraction along the profile create different conditions for plant growth and, above all, with regard to the provision of the latter with soil moisture and nutrient reserves. To bring environmental conditions in line with the needs of agricultural crops grown on soils with different content of fine-grained soil in them, the use of differentiated agricultural machinery and new technical solutions is required. (Research purpose) The research purpose is developing technological and technical solutions for the cultivation of fruit and berry products on pebble lands. (Materials and methods) Used the results of the functioning of technical means in conditions of intensive gardening. Conducted theoretical research using methods of physical and mathematical modeling, process optimization and mathematical statistics. (Results and discussion) A device has been developed, the use of which, according to the results of production tests, will allow: to involve pebble lands, inconveniences, waste areas, disturbed lands, land plots with complex geomorphological conditions in agricultural production. (Conclusions) It was shown that when implementing the proposed device in intensive gardening (up to 10 thousand columnar fruit trees per hectare), 50-160 tons per hectare of environmentally friendly products can be obtained from one hectare of an apple orchard, in berry growing, 40 to 60 strawberry bushes can be grown on one module and a harvest of 120-180 tons per hectare can be obtained, which is 1.8-2.7 times more than the yield obtained using traditional technology.

ОПТИМИЗАЦИЯ СИСТЕМЫ УПРАВЛЕНИЯ ПРОГРАММНО-АППАРАТНОГО КОМПЛЕКСА ДЛЯ УЧЕТА ЭЛЕКТРОЭНЕРГИИ

The presented article explores the topic of optimizing the control system software and hardware complex for electricity metering. The control system plays a crucial role in accurately measuring and monitoring electricity consumption. The main objective of this research is to identify and implement optimization techniques that enhance the performance and efficiency of the control system. Aim. Based on the analysis of existing electrical complexes, to develop an architecture, simulation digital models, effective control al-gorithms and methods of operation of an electrical complex based on three-phase digital measuring trans-formers with a control system of domestic production for electricity metering in high-voltage AC networks, ensuring operability and quality of functioning in various modes under various external influences. Mate-rials and methods. The scientific tasks have been solved using the general theory of electrical complexes and systems, the control systems theory, methods of physical, mathematical, simulation and computer modeling of components of electrical complexes and systems. Results. The article reflects the development of the general theory of electrical complexes, including digital combined measuring transformers and a control system in the form of a stand-alone integration module, in terms of optimizing system connections of components of electrical power metering complexes. Conclusion. The main practical result of the con-ducted research is the production of a prototype of an electrical complex based on prototypes of adaptive digital current and voltage transformers and an electrical complex control system for electricity metering based on a universal platform for measuring transformers. Such a construction of a digital three-phase measuring transformer and a universal terminal block (unification module) make it relatively easy to de-velop similar devices with other current and voltage ranges based on the developed prototype. In existing combined measuring transformers, such a combination of primary converters is not used.

УПРАВЛЕНИЕ ПЛАВАНИЕМ КОМПОЗИТНОГО ЭЛЕКТРОМЕХАНИЧЕСКОГО МИКРОРОБОТА

Relevance Currently, underwater robotics is one of the most important areas of development of robotic complexes. Their foundation and control are based on an electromechanical basis. The creation and research of electromechanical systems are one of the promising areas of development of electromechanics and electrical engineering. Equipped with a wide range of sensors, unmanned underwater vehicles are widely used to solve tasks such as studying the seabed relief, monitoring and servicing oil and gas pipelines and cable lines, collecting biological and geological samples of liquids, developing offshore oil and gas fields, conducting underwater rescue operations. The increasing popularity of such devices is explained by the fact that the use of manned vehicles can be very dangerous for the life of the pilots themselves and incur high costs during their operation. Research conducted by various engineering groups in the field of modeling and control of underwater robots is ultimately aimed at achieving full automation of processes. Achieving this aim seems to be an extremely difficult task, since it requires knowledge and understanding of a large volume of theoretical and practical problems that are subject to comprehensive research. Aim of research To carry out theoretical calculations on the study of electromechanical and mechanical parameters of underwater robot control and compare them with experimental data. Research methods The theory of electromechanical energy conversion and control of electrical equipment, methods of mathematical and physical modeling were used in the work. Results The results of constructing an algorithm and a mathematical model of the device of an electromechanical composite robot are presented. A system of equations of mechanics and electrodynamics was used to describe its power characteristics. By solving this system of equations, a theoretical analysis of the operation of its engine was carried out. With the help of the mechatronic approach, its swimming and coordination of its functional modules are studied. The results of this article will be useful for engineers involved in the design and operation of robots using robotic systems in the fields of biotechnology and biomechanics.

Optimization of Dynamically Loaded Nonlinear Technical Systems

Technological progress is impossible without new innovative developments, discoveries, inventions. Modern nonlinear technical systems cannot do without the use of friction units, which are various gears, connections, as well as complex nodes and devices. The geometrical parameters of the railway-rolling stock system were optimized when moving in curves of small radius. A unique roller rig was used to carry out model tests using the method of physical and mathematical modeling. It is proposed a method for increasing the efficiency of friction systems, which is based on fundamental research in the field of mechanics of contact friction interaction of solids. One of the technical solutions implemented on the basis of this study is the development of technology and technological equipment for increasing the traction force of a locomotive and increasing the service life of wheelsets. The theoretical basis of this technology is the anisotropy of friction junctions formed by thermos metal plating of the wheel working surfaces.

Influence of the Shape and Orientation of the Intermediate Support on Soil Washout

A sharp increase in the flow velocity and water level in rivers occurs with a large volume and intensity of precipitation, which can lead to deformations or destruction of culverts. It is possible to assess the impact of water flow using formulas and reference data from regulatory documents, and in some cases, using physical and computer modeling methods. The work is devoted to the assessment of changes in the relief of the river bottom under the action of a fluid flow near the intermediate support of the bridge crossing. Several types of intermediate supports (pile and massive) of various shapes with the same cross-sectional area are considered. The study was carried out using computer modeling methods implemented in the Flow3D program, which provides high-precision modeling of flows with a free surface.

Boundaries of flow change in an array of structures with an inclined slope

The purpose of the research is to substantiate an effective technology for the use of reinforced soil in hydraulic engineering facilities. The main task is to develop calculation methods and compare them with the results of model studies. The article uses methods of physical modeling of structures made of reinforced soil. It develops the theoretical foundations of modeling by introducing the obtained data on full-scale structures. The values of the dimensionless coefficients and the corresponding hydraulic gradients for various times are given in the tabular form, which is convenient for calculating operational parameters. To clarify the change in the boundary of the filtration flow over time, experiments were carried out in a slotted tray. The article graphically depicts the results of theoretical studies and experiments; the discrepancy between the theoretical and experimental curves for changing the boundary of the filtration flow over time is no more than 4%.

Autoregulatory of water level for channels of parabolic section and its capacity

The proposed design of the water level autoregulator with flexible working bodies for the channels of the parabolic section of the irrigation system is made in the form of a gate, which is a container formed by a rigid bottom, a pressure part made of flexible rubberized meliorative fabric, a rigid frame part of the spillway with a non-vacuum type profile covered with flexible meliorative fabric, and soft side elements also made of flexible rubberized meliorative fabric, which are a continuation of the pressure and spillway parts. Regulation of the water level in front of the autoregulator is carried out using a water level regulator. To determine the flow capacity of the gate of the proposed design of the water level autoregulator, a theoretical formula was derived, and experimental studies were carried out to determine the values of the flow coefficient included in this formula. The study was carried out on an experimental installation by the physical modeling method of the model and nature. As a result of the mathematical processing of the results of studies of the shutter model, an empirical formula was obtained for determining the shutter flow rate depending on the ratio of the iridescent water layer's thickness to the shutter's height. At the same time, the difference between the obtained values of the flow coefficients according to this formula and the results of experimental studies was +4...5 percent. This automatic water level regulator performs the function of a partition structure, does not require high costs, and can be portable and stationary; it is not metal-intensive, lightweight, transportable, combines the functions of stabilizing the required water level in the channel, dumping excess water, fin and debris, provides the necessary water enters the outlet openings of the channel.

Study on three-dimensional numerical simulation of shell and tube heat exchanger of the surface ship under marine conditions

Shell-and-tube heat exchanger (STHX) is widely used by virtue of its simple structure and high reliability, especially in a space-constrained surface ship. For the STHX of the surface ship, roll, pitch and other motion of the ship will affect the heat transfer performance, resistance characteristics and structural strength of the heat exchanger. Therefore, it is urgent to carry out numerical simulation research on three-dimensional thermal hydraulic characteristics of surface ship STHX under the marine conditions. In this paper, the numerical simulation of marine shell and tube heat exchanger of surface ship was carried out using the porous media model. Firstly, the mathematical physical model and numerical method are validated based on the experimental data of a marine engine cooling water shell and tube heat exchanger. The simulation results are in good agreement with the experimental results. The prediction errors of pressure drop and heat transfer are less than 10% and 1% respectively. The effect of marine conditions on the heat transfer characteristics of the heat exchanger is investigated by introducing the additional force model of marine condition to evaluate the effect of different motion parameters on the heat transfer performance of the heat exchanger. This study could provide a reference for the optimization of marine heat exchanger design.

Development of technology for the production of new materials on traditional wide-strip hot rolling mills using modern methods of numerical and physical modeling. Part 1

A description of the technique for developing the technology for hot-rolled coils manufacturing in the conditions of an existing production, the technology and characteristics of which go beyond the passport characteristics of the equipment, is presented. It is proposed to carry out comprehensive laboratory studies of the developed material (the kinetics of recrystallization processes during heating and rolling, the kinetics of structural transformations, material properties at production temperatures), engineering calculations of the equipment operation and simulation of the strip behavior during the rolling and coiling before the industrial testing of the hot rolled products manufacturing technology. The practical application of the proposed approach is demonstrated by the example of the development of a technology for manufacturing hot-rolled coils from low-carbon boron steel with a minimum yield strength of 1000 MPa. For the developed steel, rational temperature parameters for slabs heating are determined, which exclude the development of collective recrystallization and the formation of an uneven-grained structure, and also limiting deformation modes are defined, which ensure efficient grain refinement and implemented on existing hot strip mills. It has been established that in low-carbon steel a high strength with satisfactory ductility, low-temperature toughness, and the ability to cold forming (bending, profiling, etc.) is achieved due to the formation of a lower bainite structure in rolled products. The required structural state was obtained by applying the technology of interrupted quenching from rolling heating at massaverage cooling rates of about 25 °C/s.The studies were carried out within the program of the Russian Federation of strategic academic leadership "Priority-2030" aimed at supporting the development programs of educational institutions of higher education, the scientific project PRIOR/SN/NU/22/SP5/26 "Development of innovative digital tools for the implementation of applied artificial intelligence and advanced statistical analysis of Big Data in production processes of metallurgical products".

Gearbox fault diagnosis based on a fusion model of virtual physical model and data-driven method

Planetary gear system is widely used in wind power, construction machinery and helicopters, because of its large transmission ratio, strong load-bearing capacity and small size. Because the gears are usually in high-speed operation, their key components are subject to severe wear and impact damage. When the gearbox is subjected to a failure, it is often difficult to judge the operating status of the gearbox in real time. Since the gearbox system is complex, moreover, it is still difficult for the simulation model to accurately identify the gearbox fault. To address this issue, this paper proposes a digital twin-based signal fusion model to accurately identify gearbox faults at the signal level. The proposed model can identify minor faults occurring in planetary gearboxes by fusing actual and virtual signals. Firstly, on the basis of virtual prototype and the multibody dynamics software, a digital physical model based on Hertz theory and extended finite element method is proposed for gearbox dynamic monitoring and digital simulation, in which the gearbox can be visualized. Secondly, the data-driven method is used to extract and select features from real and simulation signals, and the fault of the planetary gearbox is detected by feature matching. Finally, the real and simulation signals are fused effectively based on variational mode decomposition and phase correction of generalized cross-correlation coefficient. The fault diagnosis result of the gearbox is finally determined by using the envelope spectrum of the fused signal. The experimental results show that the virtual real fusion method effectively improves the performance of the traditional signal diagnosis methods, and the fusion of the actual and virtual signals strengthens the fault features of the fused signals effectively.

Investigation of the relationship between tensile viscoelasticity and unloaded ultrasound shear wave measurements in ex vivo tendon

Mechanical properties of biological tissues are of key importance for proper function and in situ methods for mechanical characterization are sought after in the context of both medical diagnosis as well as understanding of pathophysiological processes. Shear wave elastography (SWE) and accompanying physical modelling methods provide valid estimates of stiffness in quasi-linear viscoelastic, isotropic tissue but suffer from limitations in assessing non-linear viscoelastic or anisotropic material, such as tendon. Indeed, mathematical modelling predicts the longitudinal shear wave velocity to be unaffected by the tensile but rather the shear viscoelasticity. Here, we employ a heuristic experimental testing approach to the problem to assess the most important potential confounders, namely tendon mass density and diameter, and to investigate associations between tendon tensile viscoelasticity with shear wave descriptors. Small oscillatory testing of animal flexor tendons at two baseline stress levels over a large frequency range comprehensively characterized tensile viscoelastic behavior. A broad set of shear wave descriptors was retrieved on the unloaded tendon based on high frame-rate plane wave ultrasound after applying an acoustic deformation impulse. Tensile modulus and strain energy dissipation increased logarithmically and linearly, respectively, with the frequency of the applied strain. Shear wave descriptors were mostly unaffected by tendon diameter but were highly sensitive to tendon mass density. Shear wave group and phase velocity showed no association with tensile elasticity or strain rate-stiffening but did show an association with tensile strain energy dissipation.The longitudinal shear wave velocity may not characterize tensile elasticity but rather tensile viscous properties of transversely isotropic collagenous tissues.

ФОРМУВАННЯ СТРУКТУРИ ЛИСТОВИХ ЗАГОТОВОК ПРИ ВАЛКОВІЙ РОЗЛИВЦІ МЕТАЛІВ

The physical modeling method was used to study the processes of formation of the structure of sheet blanks during ingotless casting-rolling of metals. At the same time, on the basis of theoretical analysis, the main parameters are determined, with the help of which it is possible to effectively control the processes of crystallization and the formation of the structure of sheet blanks. The studies carried out made it possible to establish the regularities of the influence of hydrodynamic and thermophysical conditions of pouring metal (the speed and nature of metal movement in the inter-roll space, the overheating temperature of the melt and the intensity of heat removal from it) on the processes of its crystallization and structure formation. A transparent organic alloy camphene (C10H16) was used as a modeling medium, which makes it possible to visually study these processes during the ingotless rolling of metals. Due to the transparency of camphene, the transformation of the sheet blank structure at different stages of its formation was clearly studied: the rough primary structure of the crusts solidifying on the rolls, due to their partial deformation in the rolling zone, passes into a fine-grained structure upon exiting it. The dependence of the linear rate of metal pouring on the overheating temperature of the melt and the intensity of heat exchange processes in the roller mold is shown. At the same time, the optimal ranges of values of these parameters are determined, which ensure the stability of the process of roll casting of metals. The results obtained were the basis for the development of practical recommendations for roll casting of real metals, in particular aluminum alloys of various grades. Keywords: roll casting-rolling of metals, roll mold, melt hydrodynamics, overheating temperature, intensity of heat exchange processes, sheet blank, casting speed, structure transformation.

Laboratory and field studies to ensure the regulatory framework development and the transport facilities’ safety in the wave effect conditions

This article is part of the author’s dissertation research in the field of scientific substantiation of the development and improvement of the regulatory framework for ensuring the safety of transport facilities in conditions of wave effect. The article deals with such transport structure elements as bridge piers and railway roadbeds, which are located on the shores of the seas and are exposed to wave effects, and, as a result, need to be protected. The relevance of the issue is due to the fact that an insufficient justification degree of design solutions for engineering protection structures can lead to environmental disasters and large financial losses. Usually, competent and strict regulation of the design process and survey work allows for avoiding large financial losses. Regulatory framework development will improve the reliability of transport facilities located in the wave effect zone. At the same time, technical regulations requirements must be substantiated by scientific research. The article presents some results of scientific research carried out by the author to ensure the regulatory framework development and the safety of transport facilities in wave effect conditions. The following methods of scientific research were used in the work: field observations and surveys of the coastal zone and engineering protection structures of transport facilities from wave effect and physical (hydraulic) modeling. The results of long-term field observations and surveys of the coastal zone and engineering protection structures of the railway roadbed are used: sea wall, protective wave-damping strips, groins, breakwaters, etc. at the Tuapse-Adler sections of the North Caucasian Railway and Korsakov-Nogliki of the Far Eastern Railway. The author presents laboratory studies results of the wave protection structures operation (protective slopes, wave-damping strips with retaining structures, etc.), which were carried out by the physical (hydraulic) modeling method in wave pools and flumes. Provides information about the regulations developed with the author’s participation based on the research. The expected efficiency from the practical application of the developed normative documents is described.

Study on CO2 bubble growth and detachment in liquid steel induced by thermal decomposition reaction with physical modeling

The bubbles have been widely applied in industrial processing, including steelmaking. Recently, industrial trials of natively generated bubbles via decomposition reactions have been successfully adopted in steel refining and inclusion removal. The refining efficiency was proved to be outstanding due to the small bubble sizes and the subsequent satisfying dynamic conditions. However, the bubble behaviors, including growth and detachment, are still not thoroughly clarified due to the strict requirements for observation conditions. Therefore, the growth and detachment behavior of the bubbles generated by decomposition reactions were carefully observed with physical modeling and shadow imaging method. The detachment sizes of the bubbles were extracted accordingly. Based on the statistical data on the detachment bubble sizes, a traditional nozzle flow model was modified for the prediction of the bubble detachment size in decomposition reactions. This work provides the foundation for further studies on the interaction mechanism between the natively generated bubbles and the impurities in liquid steel in terms of inclusion removal.

Numerical study of performance of flat and perforated radiant heat shields for offshore structures

Heat shields are an essential safety facility on offshore structures to protect the workers and the equipment on deck from the violent radiant heat flux and the high temperatures of the flare tower. In this study, a series of Computational Fluid Dynamics (CFD) simulations were performed to investigate the thermal characteristics of radiant heat shields on offshore structures in order to obtain a precise prediction of those reduction performances on heat flux and temperature. CFD methodologies for the radiant heat transfer simulation were suggested for grid, iteration, and time step with physical modelling methods of heat transfer considering the convection effect and the heat flux sensor, including the scaling method for the simulation of a perforated heat shield. The reduction ratios of the heat flux and temperature were obtained for the case without the heat shield and for a flat and perforated heat shield under the heat source of 25 kW/m2 for various distances from the heat shield, and the results were compared with the experimental results. Analytical estimation methods were included in the study of the radiant heat flux and temperature, and an empirical formula was provided for the performance of the heat shields based on the CFD results.

Experimental and numerical modeling of various energy dissipater designs in chute channels

Energy dissipater in the stilling basin is a structure designed to protect downstream of the spillway from erosion and scour by reducing flow energy in the energy dissipation pool. Energy dissipation pool is an important element of hydraulic structures as a transition between the high-velocity flow and the sensitive tail water. The aim of this study is to investigate the energy dissipation ratios of baffle blocks which constructed in Type III stilling basin with different geometric shapes by using physical and numerical modeling methods. In all types of baffle blocks, the block heights and widths are chosen equally, and the total baffle block lengths are designed to be 50% of the stilling basin width. Energy dissipation ratio of the baffle blocks in 4 different geometric shapes was determined in 3 different layouts as single row, two rows and two rows without threshold structure, in a total of 12 different designs and 7 different flow rates are tested. In addition, these experimental studies were tested in the FLOW-3D software program, and the results of experimental and numerical studies were compared. As a result of the study, it was determined that the T-shaped energy-dissipating block had the highest energy dissipation ratio, and it was observed that the results obtained from the experimental studies and the FLOW-3D software were similar to each other with in the range of 5%.