scholarly journals Profiling of sudden contraction of circular pipe by sharp-edged pipe insert

2021 ◽  
pp. 48-55
Author(s):  
Bohdan Pitsyshyn ◽  
Vadym Orel ◽  
Tetiana Konyk
Keyword(s):  
Single Phase ◽  
Mutual Influence ◽  
Length Ratio ◽  
Transport Systems ◽  
Circular Pipe ◽  
Design Stage ◽  
Mathematical Experiment ◽  
Inlet Length ◽  
Recirculation Length ◽  
Flow Devices

Measures to reduce energy losses in pipeline transport systems must be implemented already at the design stage. In particular, this also applies to local resistances of pipelines. For symmetrical sudden pipe contraction, one of such measure is profiling using insert. The paper considers a sharp-edged pipe insert, which in comparison with others has larger areas of flow separation. The diameter of the insert was calculated as the arithmetic mean between the diameters forming the sudden pipe contraction. Using the methodology described in the literature, the contraction length ratio as the areas of influence between two symmetrical sudden contractions of a circular pipe during the flow of a single-phase turbulent flow of Newtonian fluid was investigated. The coefficient of mutual influence of these local resistances was determined by formulae for direct-flowing and non-direct-flowing locking devices, which simulated symmetrical and asymmetrical fluid flow after the constriction plane, respectively. The contraction rate from 0.064 to 0.696 inclusive are considered. According to the results of calculations, no mutual influence of two sudden contractions of circular pipe was found. This indicates the unsuitability of using formulae for locking devices in this methodology for determining the contraction length ratio. Therefore, to study this problem on the sudden pipe contraction with different contraction rates, it is proposed to conduct a physical experiment. In a mathematical experiment, you can use formulae to determine the following values: upstream recirculation length and downstream recirculation length; inlet length of cylindrical pipes with turbulized the flow devices; length of the velocity profile stabilization after local resistances.

scholarly journals THE SYSTEM OF ROLLING-STOCK’s PARAMETERS OF INTERMODAL PIGGYBACK TRANSPORTATION

2020 ◽  
Vol 17 (2) ◽  
pp. 262-272
Author(s):  
A. V. Tsyganov ◽  
N. A. Osintsev
Keyword(s):  
Systems Approach ◽  
Mutual Influence ◽  
Transport Systems ◽  
Rolling Stock ◽  
Necessary Condition ◽  
Operational Parameters ◽  
Weight Restrictions ◽  
The Road ◽  
On The Road ◽  
Railway Rolling Stock

Introduction. The priority area of transport systems development is the formation of transport corridors with multimodal systems and intermodal cargo delivery technologies, ensuring the achievement of economic, social and environmental goals facing the countries. For the transport system of Russia, which claims to advance transit cargo flows through its territory, the solution to the above problems can be achieved by organization of the piggyback transportation. A necessary condition for the organization of effective piggyback transportation in domestic and international traffics is the systematization of parameters and the assessment of technical compatibility of the involved rolling-stock.Methods and models. A systems approach is used to represent piggyback transportation as a complex technical system consisting of road vehicles, domestic and foreign railway rolling-stock interacting in intermodal terminals. The ER-model is used to describe the conceptual scheme of the piggyback system.Results. The parameters of the road and railway rolling-stock are justified and systematized, their mutual influence is determined at the level of compatibility of their technical and operational parameters in the organization of domestic and international piggyback transportation. Systematization, structuring, storing and updating of rollingstock parameters are carried out using the database «Determining the rolling-stock basic parameters of piggyback delivery systems» developed in Microsoft Access.Conclusion. The developed system of parameters allows to assess technical compatibility of road and railway rolling-stock of the countries participating in piggyback transportation, and can also be used for unification of intermodal transport units and harmonization of the overall weight restrictions on the road and railway networks.Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

scholarly journals Desain Inverter Satu Fasa 12V DC ke 220V AC Menggunakan Rangkaian H-Bridge MOSFET

2019 ◽  
Vol 3 (1) ◽  
pp. 1-12
Author(s):  
Andhika Giyantara ◽  
Risky Susanto Tjiang ◽  
Subchan Subchan
Keyword(s):  
Single Phase ◽  
Bridge Circuit ◽  
Block Diagram ◽  
Oxide Semiconductor ◽  
Design Stage ◽  
Switching Speed ◽  
Electric Voltage ◽  
Fast Switching ◽  
Effect Transistor ◽  
Single Phase Inverter

Inverter is an electronic circuit that convert electric voltage with direct current (DC) to alternating current (AC). One of the commonly used inverter configuration is H-Bridge circuit. Inverter with H-Bridge circuit does not need voltage-balanced diode or capacitor to operate and can be cascaded to obtain multilevel output voltage. H-Bridge circuit works by adjusting the combination of switches that were enabled. One of the commonly used switches is Metal Oxide Semiconductor Field Effect Transistor (MOSFET). The advantages of MOSFET as switching components are its fast switching speed and it did not cause current tail. Therefore, the writing of this paper aims to design a 12V DC to 220V AC 50Hz single-phase inverter with H-Bridge MOSFET circuit. The design stage begins with determining the specifications of the inverter, creating a block diagram of the inverter, determining the required components, and calculating the required parameters of the inverter. The designed inverter is simulated using Proteus 8.4 software. Simulation results are in accordance with the desired specification.

scholarly journals Increasing calculation accuracy in the design stage of a gas transportation system

2013 ◽  
Vol 24 (2) ◽  
pp. 61-66
Author(s):  
Sorin Neacşu ◽  
Renata Rădulescu
Keyword(s):  
Critical Evaluation ◽  
Accurate Method ◽  
Transportation System ◽  
Transport Systems ◽  
Final Part ◽  
Design Stage

AbstractThe paper presents a critical evaluation of the equations used to calculate the flow and pressure for transport pipelines. A highly accurate method for calculating gas parameters is proposed. The final part of the paper presents some comparisons between the proposed method and modern simulators used for the design of transport systems.

scholarly journals Calculated estimation of electromagnetic compatibility of radio-electronic means of space systems and complexes

2021 ◽  
Vol 24 (2) ◽  
pp. 49-54
Author(s):  
Yevgeny E. Krivobokov
Keyword(s):  
Electromagnetic Compatibility ◽  
Mutual Influence ◽  
Integrated Approach ◽  
Design Stage ◽  
Launch Vehicles ◽  
Space Systems ◽  
Space Technology ◽  
Radio Electronic ◽  
Analytical Assessment ◽  
Technical Measures

This article presents the methods of complex computational and analytical assessment of ensuring electromagnetic compatibility of technical means (electrical, electronic and radio-electronic means of launch vehicles and spacecraft). These methods allow us to conduct a comprehensive computational and analytical assessment of the electromagnetic compatibility of the technical means of rocket and space technology, which in its essence allows us to assess the mutual influence of the technical means of rocket and space technology already at the design stage of rocket and space technology objects. The analysis of the results of the assessment of the electromagnetic compatibility of the technical means of rocket and space technology allows us to develop organizational and technical measures aimed at ensuring the electromagnetic compatibility of the technical means of rocket and space technology at all stages of the life cycle of objects of rocket and space technology. To assess the electromagnetic compatibility of the technical means of rocket and space technology, an integrated approach was chosen due to the large dimension of the initial data and the variety of possible variants of interference penetration.

Co-Current Gas-Liquid Smooth-Stratified Flow in a Horizontal Reduced T-Junction Including Wavy and Slug Regime Transition Boundaries

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Robert C. Bowden ◽  
Ibrahim G. Hassan
Keyword(s):  
Single Phase ◽  
Inlet Pipe ◽  
Critical Height ◽  
Two Phase ◽  
Gas Entrainment ◽  
Inlet Length ◽  
Phase Liquid ◽  
The Relationship ◽  
Stratified Regime ◽  
Good Agreement

Experiments were performed in a horizontal reduced T-junction using a branch diameter of 6.35 mm and an inlet pipe diameter of 50.8 mm. The inlet length was 1.8 m and three branch orientations were tested at 0, 45, and 90 degrees down from the horizontal. Water and air, operating at 206 kPa, were used to provide an adiabatic two-phase environment. Both fluids flowed co-currently within the inlet towards the branch in the smooth-stratified regime. Results demonstrate the relationship between the interface height and the inlet and branch two-phase quantities, including the inlet superficial liquid and gas velocities, and branch two-phase mass flow rate and quality. In certain instances transitions to wavy-stratified or slug regimes were observed and these limits are quantified for each branch orientation. Flow visualization was used to identify the initiation of two-phase flow in the branch, including the onsets of gas and liquid entrainment. The critical height at the onset of gas entrainment was quantified as a function of the single phase liquid branch Froude number for the 45 and 90 degree branches, respectively. The branch quality results were scaled using the critical height and showed good agreement with selected models.

scholarly journals Exploring the Patterns of Resident Resettlement in Rural and Suburban Areas and Their Influence on the Passenger Trip Generation

2022 ◽  
Author(s):  
Mykhailo Krystopchuk ◽  
Tatiana Krystopchuk ◽  
Igor Khitrov ◽  
Igor Bugayov ◽  
Dmytro Burko ◽  
...  
Keyword(s):  
Computational Geometry ◽  
Mutual Influence ◽  
Spatial Interaction ◽  
Three Dimensional ◽  
Economic Consequences ◽  
Transport Systems ◽  
Passenger Transport ◽  
Functional Connection ◽  
Control Factors ◽  
Transport Services

The region is a complex multi-element and heterogeneous dynamic system. Regional public transport systems are characterized by heterogeneity and incompleteness of information about the processes that take place in them. The factors determining the demand for public passenger transport services, the structure of suburban population transit and the economic consequences of changing this structure have not yet been sufficiently investigated. There is no quantitative assessment of the control factors’ influence on the results of the passenger transport system functioning in suburban traffic, which complicates the effective management in this field.In order to determine the mutual influence of objects with unclear functional connection, one of the methods of computational geometry is considered, which allows quantifying and obtaining tabulated functions of various components and parameters of settlements' interaction and centers of gravity. The numerical characteristics obtained by the described method are further used in the modeling of the processes of efficient functioning and collaboration of urban passenger transport with other external transport types, in particular at interchanges.As a result of the proposed operations, we obtain a tabulated function of the investigated parameter for the area of spatial interaction of infrastructure objects and visualize the calculated parameters in the form of graphical dependencies or in the form of a three-dimensional surface. Thus, using the method of computational geometry, with constructing a Voronoi diagram and executing the Delaunay triangulation, it is possible to obtain tabulated characteristic parameters for inhomogeneous zones of mutual influence where infrastructure objects with unclear functional connection are located.

SIMULATION OF EMERGENCY MODES OF SEPARATOR UNIT

2021 ◽  
Author(s):  
Я.М. КАШИН ◽  
Л.Е. КОПЕЛЕВИЧ ◽  
А.В. САМОРОДОВ ◽  
Е.А. МАРАХОВСКИЙ
Keyword(s):  
Transient Process ◽  
Single Phase ◽  
Design Stage ◽  
Application Software ◽  
System Of Differential Equations ◽  
Model Based ◽  
Simulink Simulation ◽  
Short Circuits ◽  
The Relationship ◽  
Semicircular Cross Section

Предложена конструкция сепараторной установки, отличающаяся от существующих тем, что ее основание выполнено с кольцевыми канавками полукруглого сечения, посредством которых ротор-барабан установлен с возможностью вращения на неферромагнитные шарики. Кроме того, подогрев сепарируемого продукта в установке осуществлен с использованием неизбежного тепловыделения в обмотках установки путем пропускания сепарируемого продукта по трубкам, которыми обвиты лобовые части обмоток установки. Для исследования аварийных режимов этой установки (обрывов фаз, короткого замыкания) и получения ее динамических характеристик разработана математическая модель в виде системы дифференциальных уравнений, описывающей взаимосвязи между ее параметрами (сопротивления обмоток статора и ротора, число витков в них) и параметрами переходных процессов (ударные токи, длительность переходного процесса). Смоделирована работа сепараторной установки при обрыве одного фазного провода с помощью пакета прикладных программ Simulink – Simulation and model-based design (MATLAB). Разработанная модель позволила оценить влияние параметров статора и ротора установки на переходный процесс в аварийных режимах и учесть это влияние на этапе проектирования. Преимущества предлагаемой установки – повышенная надежность, улучшенные энергетические и массогабаритные показатели. The design of the separator unit is proposed, which differs from the existing ones in that its base is made with circular grooves of semicircular cross-section, through which the rotor-drum is mounted with the possibility of rotation on non-ferromagnetic balls. In addition, the heating of the separated product in the installation is carried out using the unavoidable heat generation in the windings of the installation by passing the separated product through the tubes that are wrapped around the front parts of the windings of the installation. A mathematical model in the form of a system of differential equations describing the relationship between its parameters (the resistance of the stator and rotor windings, the number of turns in them) and the parameters of transients (shock currents, the duration of the transient process) has been developed to study the emergency modes of this installation (phase breaks, short circuits) and to obtain its dynamic characteristics. The operation of the separator unit in the event of a single phase wire breakage is modeled using the Simulink is a Simulation and Model-Based Design (MATLAB) application software package. The developed model allowed us to estimate the influence of the stator and rotor parameters of the plant on the transient process in emergency modes and to take this influence into account at the design stage. The advantages of the proposed installation are increased reliability, improved energy and weight and size indicators.

Interrelation and interdependence in the framework of categories for the transport systems development and economic growth promotion

2020 ◽  
pp. 111-122
Author(s):  
L. M. Chechenova ◽  
Keyword(s):  
Economic Growth ◽  
System Analysis ◽  
Mutual Influence ◽  
Growth Promotion ◽  
Practical Importance ◽  
Subsequent Development ◽  
Transport Systems ◽  
Modeling Methods ◽  
Transport Industry ◽  
Complex Methods

Objective: To establish a connection between the development of the transport system and the economic growth category, with subsequent defining of the principles of interdependence and mutual influence. Methods: Complex methods of system analysis and economic and mathematical modeling methods have been used. Results: The scientific background has been analyzed as regards the development of transport systems and subsequent economic growth. Based on the corresponding principles of interdependence and mutual influence of the development of transport systems and the economic growth category, possible connections between the components compared have been modeled. Economic and mathematical models of economic growth are proposed, which characterize state investments in the transport industry with its subsequent development, and investments with subsequent economic growth of the country. Practical importance: The practical value of the study involves using its main results for assessing the effectiveness of development projects implemented in the transport industry. The proposed models can be used for critical analysis, diagnostics and subsequent assessment of transport systems functioning

Sign in / Sign up

Export Citation Format

Share Document