bluuebunny/crossref_metadata_2025 huggingface dataset:
System-targeted approach to the integrated use of transport in the interests of life safety
Authors: Kazaryan Ruben
Published: November 2018

The technical component of the MTE system (man-technology- environment), a special case of which are the means of mechanization and transportation (MMT) in construction, is investigated as it develops in terms of reliability and efficiency of the processes of construction production implemented using MMT. Firstly, there is no evaluation of the economic justification for an integrated transport communication system. Secondly, there are economic and mathematical models of the integrated use of different types of transport in the interests of ensuring environmental safety. Thirdly, there are methodologies of economic justification of the complex use of transport in the interests of environmental safety. Certification of means of mechanization of manual labor and transportation of building cargo and structures (MMT) is one of the important packages of construction production objects for services of high-rise construction. The variety of certification aspects corresponds to the variety of domestic and foreign production used in the conditions of market competition in the construction of MMT, in particular, the means of road transport in construction (MRTC). High dynamics of transport support for economic, social, demographic, and environmental security in a market economy require the creation of a concept for the integrated use of transport in the interests of Russia's national security. The demand for systematic consideration of three components (human, engineering, and environment) from the positions of system engineering of construction, the theory of functional systems and modeling of their mutual influence is identified with the main role of the subject-object approach to the comfort and workability criteria, organizational- technological and organizational-anthropotechnical reliability of the MTE system.
Integrated safety system for workers and traffic in railway transport
Authors: Basalaeva Anna , Medvedev Vladimir , Strykov Pavel
Published: November 2018

The safety and stability of the transportation process in railway transport is provided by a set of various measures. However, violations, incidents and accidents continue to occur, causing significant damage to workers, infrastructure, natural environment, and population. The relevance of the study is determined by the need of finding ways to prevent this damage and reduce the socio-economic and environmental costs. The purpose of the study is the development of an integrated safety system for traffic and workers in railway transport. A set of theoretical and experimental research methods has been applied: physical, simulation and computer modeling; statistics, theory of probability and others. The main result of the development is a complex system of interrelated units: “Sphere of activity”; “Qualification of personnel”; “The required level of work”; “Rating of danger”; “Optimization and technical and economic assessment of company costs”. Requirements for an information management system were developed for the holding company “Russian Railways”. This system allows personal accounting of the qualifications of employees (over 900 thousand) in the main areas of activity: ensuring traffic safety; occupational safety and health; transport, industrial, fire and electrical safety; protection in emergency situations. The project of the normative and technical document regulating the corresponding changes is substantiated. On the basis of theoretically processed experimental material, the expected development efficiency was established: 8-10%.
Influence of opposite elevation on the occupancy level of the tracks of sorting park
Authors: Bessonenko Sergei , Kornienko Konstantin , Tanaino Iuliia
Published: November 2018

The purpose of this paper is to study the effect of the location and magnitude of opposite elevation on the occupancy level of the tracks of sorting park. The subject of the study is the effect of the magnitude and location of opposite elevation on the sorting tracks occupancy level. The object is the tracks of sorting park. For the study, a simulation model of the traffic of the cut in sorting park was used, taking into account the reverse movement, “SortPark”. On the basis of this model, it was concluded that when the target point is moved farther from the braking position, the distance traveled by the cut first increases, and then decreases. This is due to the fact that when stopping the cut on the opposite elevation, it can start to move backward. On the basis of this, it was concluded that the useful length of the sorting yard track for the first detaching limited by the point of change of gradient from grade to opposite elevation. In view of this conclusion, the formula for determining the sorting track occupancy level was improved.
Consideration of quality change of railway transport maintenance operations in managing costs of goods transport
Authors: Shkurina Lidia , Maskaeva Eugenia , Maskaev Stanislav
Published: November 2018

the authors reviewed the quality of operational work of railway transport in the cost management system, presented methods for assessing the impact of the quality of rolling stock on the current costs of transportation activities, considered the issues of the impact of the quality of operational work on the formation of freight market demand and of financial result of the transport company - the owner of infrastructure and traction rolling stock, represented methods of assessing financial and economic efficiency of improving the quality of operational work for the company - a participant of the freight market.
International legal regulation of road transportation (features of the legal consciousness of legislators)
Authors: Bryukhov R.B. , Kovalenko K.E.
Published: November 2018

The contract of international carriage is a special type of foreign economic transactions. The specificity of this agreement is due to the peculiarities of transport as a natural monopoly of the state. The contract of international carriage includes public law (determination of the status of the transport environment) and private law (direct organization of the carriage itself) aspects. International carriage is the carriage of goods and passengers between two or more states in accordance with the terms of an international agreement concluded between them.
Forecasting of traffic flows and their development in the implementation of the transport strategy in the Far North
Authors: Buneev Viktor , Vinichenko Victoria , Maslennikov Sergey
Published: November 2018

The purpose of this study was to determine the role of public policy in creating a favorable environment for the development of the national economy and improve social and economic well-being through the creation of a safe and convenient transport structure. Special attention of the authors is drawn to the Decree of the government of the Russian Federation of 22.11.2008 No 1734-R "On the transport strategy of the Russian Federation". The purposeful value of the above mentioned by-law is considered. As an indicator of the quality of transport services "Transport strategy of Russia until 2030", it assumes a steady increase in transport mobility of the population of the Russian Federation, as well as the integration of the Russian transport system into the international one. The results of forecasting of some key indicators of the Transport strategy are presented. Since the implementation of the strategy was actually launched back in 2009, it is already possible to judge the achievement (or, more precisely, the lack of achievement) of the criteria considered. It was found that there was a close link between the quantity of goods carried and the quantity of goods overloaded the net financial result and some other indicators. Feedback was identified between the same trait under study and the wear and tear of fixed assets. Thus, knowing the factors that have a direct impact on the result, you can manage it. And the achievement (or non-achievement) of the target indicators becomes an elective parameter influencing firstly on the variant of the development scenario (basic or innovative), and secondly, on the social and economic situation of the studied region. The main task of the state in the sphere of functioning and development of transport system of Russia.
Organization of railway track tamping work using the software and hardware complex SMTC
Authors: Manakov Aleksey , Kolarzh Sergey , Mashkov Aleksey
Published: November 2018

The main purpose of this work is to study the applicability of the hardware and software complex “Monitoring system for the technical condition of track equipment” to monitor the performance of track operations. The methodological base of study is formed on the basis of the analysis of scientific works of domestic and foreign scientists and the systematization of statistical data on the organization of the system of technical operation of track machines at enterprises of the West Siberian Railway. As a result of the study, it was proved that the functional of the system for remote monitoring of the technical condition of track equipment, which was developed by the specialists of the Siberian State Transport University, allows for continuous monitoring of the performance of track operations. Quality control of works is carried out on the basis of an estimation of parameters of functioning of working elements of the track equipment involved in the process of work performance. The application of the developed software and hardware complex allows significantly reducing the financial losses of railway transport enterprises associated with the repeated performance of track operations. The problems to be solved with the help of the proposed control system correspond to the priority areas of the Strategy for the Development of Railway Transport in the Russian Federation until 2030 in the development and implementation of means for automating control of infrastructure.
Automation of monitoring and diagnosing the technical condition of torpedo ladle cars
Authors: Yemelyanov Vitaliy , Tochilkina Tatiana , Nedelkin Alexey , Shved Evgeny
Published: November 2018

The paper presents data on the problem of monitoring and diagnosing the technical condition of torpedo ladle cars at the iron and steel works. The structure of technology for automated monitoring and diagnosing the technical condition of torpedo ladle cars has been developed and described, as a system-organized sequence of operations performed with the information on the state of the torpedo ladle cars applying the proposed methods. There has been developed software to implement the operations of information processing for torpedo ladle cars and to support decision-making on selecting their operational mode.
Methods of studying the characteristics of hydraulic systems of loading machines on a laboratory hydraulic stand
Authors: Ezhov Yuri , Zub Igor , Pizhurina Natalia , Sidorenko Vladimir
Published: November 2018

The operation of loading machines requires special attention in the selection of materials for hydraulic devices and the development of recommendations for their operation. Competencies that should be obtained by a specialist operating the handling equipment, include the ability to analyze the operation of the hydraulic system on the basis of these devices and adjust the operating modes of the handling devices. In this paper, a number of experiments on the hydraulic bench. During the experiments, the characteristics of the pressure dependence in the lifting cylinder on the weight of the load and the lifting angle were removed. The considered algorithm of research can be used in the development of methods of laboratory work for the training of specialists in the field of operation and design of loading equipment.
Legal regulation of aircraft leasing
Authors: Akhmetshin Elvir , Kovalenko Kseniya
Published: November 2018

Currently, flights are an integral part of our lives. Sitting in the plane, we trust our lives not only to the crew but also to the aircraft. Today, the requirements for aviation are extremely high. But do not forget that the aircraft on which we fly are often the subject of a lease agreement. And we would like to consider the issues of aviation leasing in this article. In the legislation and the theory of civil law, there are no concepts of the contract of aviation leasing and the contract of leasing of aircraft. The leasing contract for aircraft is a contract in accordance with which the lessor undertakes to acquire into the ownership of the aircraft (plane) specified by the lessee for business or other professional purposes from the seller specified by him and provides the lessee with this property for a fee in a temporary possession and use. The contract may provide that the choice of the seller and the acquired property is determined by the lessor. In doctrine and practice, there is no consensus on the nature of the leasing agreement, nor can scientists agree on the nature of such a treaty: whether it is trilateral or bilateral, or represents two contracts (leasing and delivery). In civil law, one of the most controversial issues is whether the leasing agreement should be considered as an independent type of a civil law contract or a type of lease.
Correlation of norms of federal and regional legislation as a condition for building an integrated system for regulating civil law relations (on the example of transport regulation)
Authors: Semeryanova Nina , Kopytova Anna , Dolnikova Ludmila , Morozkov Vladimir
Published: November 2018

The urgency of the problem under investigation is caused by the contradictions between regional and federal legislation in the regulation of civil relations, which hamper the optimization and achievement of the balance of the Russian legislative framework. Such contradictions are most clearly seen in the field of transport law. The purpose of the article is to update the problematic issues of the correlation between the norms of regional and federal legislation, the issues of delimitation of private and public regulation. The leading approach to the study of this problem is dialectics, analysis, synthesis, deduction, formal-legal method. The analysis can help to understand the formative elements of law governing the legal field of private and public regulation, the adoption of regional instruments that contribute to the full and comprehensive regulation of civil relations, including the field of transport commitments.
Formation of a labor activity incentive system for workers in a transport company
Authors: Kopytova A.V. , Zotkina N.S. , Reshetnikova I.G.
Published: November 2018

The article presents the author's algorithm for the formation of a rational incentive system consisting of eight stages. Its use allows the transport company to form a rational incentive system that focuses on a specific of the company, but is built on the universal algorithm, which allows taking into account the conditions of both external and internal environment.
Ranking of transport companies innovative activity
Authors: Minnullina Anna , Astafieva Natalia
Published: November 2018

Methodological basis for assessing the innovative potential of transport companies is based on the use of the ranking model. This model is used to determine the ranking of innovative potential of the company, taking into account a number of key internal and external indicators of its activities. The proposed ranking model for determining the innovative potential has been tested in three existing transport companies of Tyumen. The testing confirms the universality of the procedure of the ranking score and makes it possible to use it in practice. The indicator allows assessing the position of the transport company and developing a strategy for its further development.
Planning and managing resources of transport enterprises
Authors: Terskikh Viktor , Katargin Vladimir , Morozova Natalia
Published: November 2018

The paper considers a new approach to planning and forming a stock of spare parts necessary for the smooth functioning of transport enterprises. The basis of the author's approach is the developed simulation model of the warehouse adapted for any type of enterprise that serves and (or) operates road transport. The need for spare parts in this model is defined as a mixture of probability distributions of demand of various kinds, which makes it universal. The model was based on the new patterns of influence of following factors on the size of the stock revealed by the authors: the statistical indicators of the need for spare parts, the type and location of the enterprise, the target level of reliability of the supply system, etc. The proposed approach allows connecting the main indicators of the resource management effectiveness: the shortage rate, the cost of stock, the level of system reliability. It allows planning and forming a stock of spare parts reasonably. It is expected that the proposed approach will increase the efficiency of transport enterprises and the degree of satisfaction of consumers of their services.
System and technical basis for introduction of overpass aerotrain transport in the transport system of the region
Authors: Vladimirova Tatiana , Sokolov Viktor , Sokolov Sergey
Published: November 2018

The purpose of the paper is to demonstrate the adequacy of the technical and economic characteristics and consumer properties of the new overpass aerotrain transport to the geographical and climatic conditions of the region. It examines the opportunities and positive results of introducing a new mode of transport in the unified transportation system of the region in order to create favorable conditions for providing necessary transport sufficiency for its social and economic development.
Mechanical and mathematical model for estimating the wear rate of the side face of rails
Authors: Karpushchenko Nikolay , Trukhanov Pavel
Published: November 2018

The paper presents a mechanical and mathematical model for estimating the wear of rails in the form of a generalized indicator called the wear factor, which includes the total relative sliding caused by turning the truck when entering the curve and rotating the wheel. The wear factor also includes the normal pressure at the point of contact between the wheel flange and rail, the contact area, the friction coefficient, and the coefficient that takes into account the wobble of wheel sets.
Specifics of determining the tension forces of the cable-stayed bridge elements
Authors: Chaplin Ivan , Yashnov Andrey
Published: November 2018

Objective: to improve the method of determining the force in the cable stays by frequencies of natural transverse oscillations. Methods: synthesis and analysis of theoretical and experimental data, experimental methods for studying the structures. Results: in the paper, the problems of determining the tension forces of the cable stays by the frequencies of their natural oscillations are considered taking into account various factors (the design of anchor fastenings, the angle of inclination and sagging of the cable stay, the change of temperature). The estimation of possible errors in calculations is given. The degree of coincidence of the actual and design stress-strain state of the cable stays depends on the correctness of accounting the influence of the factors considered. The effect of the temperature change and the anchor fastening structure on the frequency of the natural oscillations of the cable stays has been experimentally tested. The recommendations on the determination of the forces in the cable stays by dynamic parameters are given. A method for controlling the tension forces of the cable stays and specialized software “Vant” (“Cable”) for automation of the measurement process are developed. The method has been tested on several bridge structures that have cable-stayed elements. Practical significance: the ability to use the developed method for controlling the tension forces of cable-stayed elements during the operation of artificial structures.
Tangential forces in the contact area of upper road layer with the base
Authors: Gavrilov Timmo , Kolesnikov Gennady , Khoroshilov Konstantin
Published: November 2018

Low-temperature cracking is one of the main reasons for the deterioration of the upper layer of roads in regions with cold winters. A large number of works focused on deterioration prevention are known, however the interdisciplinary problem of low-temperature cracking remains relevant. The important, but insufficiently studied factor is the distribution of normal and tangential (shear) forces acting on the upper layer of the road. The objective of the current study was to clarify insight about the distribution of tangential forces in the contact area of the upper layer of the road with the base. There are works in which it is assumed that these forces are distributed by a piecewise linear law. We propose a mechanical and mathematical model and an analytical solution to the problem of the distribution of shear forces in the contact area of the upper layer with the base. The main result of the study: it is found that the distribution of shear forces in the segment of the asphalt concrete layer is described by a second-order polynomial. However, the shear stresses are distributed linearly over the entire length of the segment and reach the highest modulo values in the area of the end sections of the segment. The results of the presented study clarify the understanding of functioning of the upper road layer at low temperatures. By that, the contribution to the solution of the problem of increasing the crack resistance of roads in regions with cold winters is made.
Behavior of foundation soil improved by stone column under cyclic load
Authors: Fahmi Kwa Sally , Fattah Mohammed , Shestakova Alena
Published: November 2018

This paper deals with using the stone column as a technique for the enhancement of the soft ground. The key goal of utilizing stone column is to decrease settlement and to increment the soil bearing ability, as well as decreasing the consolidation period. Nowadays, the current method concerns with various kinds of soil granular and cohesive. It is clear that the delicate soils (cohesive) possess a good settlement because of the disability of the ground to control the sidelong development and protruding of the stone sections. Moreover, the ways of utilization of the geosynthetic materials for encasement of the stone sections are other perfect ways to enhance the implementation, the quality, and firmness of stone segments. The present work investigates the behavior of the soft soil reinforced with ordinary and encased stone columns with geogrid under cyclic load. Six model tests were carried out on a soil with shear strength of about 15 kPa for both ordinary stone columns (OSC) and geogrid encased stone columns (ESC). For validating the enhanced method of utilizing stone columns, finite element model using the software PLAXIS 3D and field load exams had been applied. It was concluded that the models subjected to cyclic loading under the rate of loading 10 mm/sec reached the failure level faster than models tested under the rate of loading 5 mm/sec. The results of the finite element analyses of settlement compared with the records of settlement after the laboratory load tests seem to yield reasonably comparable values up to 50% of the design load. Afterwards, the recorded settlements show up to 60% higher values in compare with the results of the finite element analyses. This observation can be attributed to the occurrence of plastic failures under increasing load after an initial elastic response.
Utilization of ash from power plants for high embankments on soft soil
Authors: Jocković Sanja , Pujević Veljko , Marjanović Miloš
Published: November 2018

The ash landfills are a major environmental issue. The use of ash for the highway and railway substructure achieves a double benefit: it significantly reduces the deposited quantities of ash as well as the consumption of natural materials such as crushed stone, gravel and sand. The investigation of engineering properties of fly ash from the power plant in Serbia was conducted at the Laboratory of Soil Mechanics at the Faculty of Civil Engineering in Belgrade. Relevant physical and mechanical properties of ash and mixtures with binders (cement/lime) were investigated. The ash was also tested from the aspect of the potential environmental impact, which primarily depends on the leaching behaviour of the present trace elements. The results of the study showed that fly ash meets technical and environmental requirements and that has the potential for use in highway substructure, such as construction of embankments and stabilization of soft soils. Benefits of utilization of ash and slag was shown in the case of the construction of a high embankment on soft soil on the highway section Obrenovac-Ub in Serbia.
Ways of application of the provisions of mechanics of bodies with cracks to the calculation of asphalt concrete on strength and plasticity
Authors: Aleksandrov Anatoly , Aleksandrova Natalya , Chusov Vasiliy , Riabov Aleksandr
Published: November 2018

The report discusses the principles of two major theories of fracture mechanics of bodies with cracks, which include the theory of accumulation of damage Kachanov–Rabotnov and theory of brittle fracture Griffith–Irwin, including the invariant integral Cherepanov–Rice, describing the criterion of growth the crack. To assess the application of these theories to the calculation of asphalt concrete, laboratory test data are given and based on their analysis the appropriate conclusions.
Determination of the region of the limiting states occurrence in RVS-20000 with the subsidence of the external bottom contour
Authors: Chepur P.V. , Tarasenko A.A. , Gruchenkova A.A.
Published: November 2018

The problem of the limiting states occurrence in the structures of a vertical steel tank is investigated in this work. To study the SSS of the metal structures of the object, the authors created a numerical model of the RVS-20000 tank in the ANSYS software complex. The model considers the maximum number of elements with their geometry and connections affecting the tank SSS under non-axisymmetric loading, including beyond the elasticity of steel. Dependences between the parameters of intrinsic stiffness of the VST are obtained. The results of the finite element analysis made it possible to develop a technique for assessing the technical condition of the structure with the development of irregular subsidence of the external bottom contour. The proposed technique can be used by both operating and design organizations in making managerial decisions regarding the repair of RVS-20000 subjected to the base subsidence.
Analysis of the stress-strain state of a tank in case of irregular subsidence along the periphery
Authors: Chepur Petr , Tarasenko Aleksandr , Gruchenkova Alesya , Guan Youhai
Published: November 2018

In the article, the authors proposed a calculation model for determining the SSS of a vertical steel tank in case of irregular subsidence of the external bottom contour in accordance with the geometric parameters of a real RVS-20000 m3 tank. An experiment is planned and presented including a scheme with two influencing factors: the geometric model of the tank and the value of the dimensionless coefficient m. The influencing factors have 3 and 5 combinations respectively, which is represented in the experiment matrix. The article shows diagrams of displacements, stresses of the tank structures, and graphically depicts the dependences of the displacements of shells on the values of subsidence zones. The presence of a stiffening ring and a stationary roof provides the least values for vertical and horizontal displacements. Conclusions about the influence of the factors considered on the SSS of a tank in case of irregular subsidence of the external bottom contour are presented.
Differentiated sources of funding road infrastructure
Authors: Shibaeva Marina , Okolelova Ella , Shalnev Oleg
Published: November 2018

Article reveals the growing need for increased investment in projects for the modernization and development of the motor road network and identifies the problem of high capital intensity of road construction facilities and the duration of the investment payback period that hinder the inflow of private investments. By analyzing the economic aspects of road infrastructure, the authors have developed the economic and mathematical model for optimizing the placement of asphalt-concrete plants and the cost of producing the asphalt mix, the algorithm for optimizing the cost of road facility construction, the algorithm for selecting effective investment options for commercial roadside projects.
Modeling assessment of investment risks in the regional socio-economic system
Authors: Butko Evgeniy , Selivanova Lyudmila , Vasileva Natalia
Published: November 2018

The paper defines methodological approaches to the assessment of investment risks in the social and economic system of the region. Based on the analysis of the conducted studies, a new model for assessing investment risk at the regional level in the conditions of certainty, uncertainty, and risk is proposed, which will allow assessing the probability of losing funds from investing financial resources. As a part of this model, a methodology for developing and making decisions under different conditions depending on the determinism or randomness based on the availability of information is presented. The calculations made allow choosing the optimal strategy of investment in the regional economy with different risk indicators, which are determined as the average annual rate of inflation.
Marketing analysis of the residential real estate sector as a tool to plan the development of transport infrastructure
Authors: Lavrinenko Yaroslav , Tinyakova Victoria , Shishkina Larisa
Published: November 2018

Current methods for analyzing the residential real estate market have certain disadvantages. First of all, they are related to the heterogeneity of the market due to geographical differences. Secondly, it is various approaches to analyze the real estate sector. The real estate market is often analyzed only from the point of statistics and macroeconomic phenomena, without taking into account marketing components. However, effective analytics of the real estate sector should include marketing analysis. This analysis helps to understand the preferences and trends of past and current customers, specifically favored price. A forecast of future trends in real estate is created on the basis of this analysis. The authors suggested methodological approaches to analyzing the residential real estate sector with the use of marketing analysis.
Cost accounting in transport companies
Authors: Gerasimova Larisa
Published: November 2018

The article shows that the main task of business development related to transport is obtaining of the required financial result while observing cost optimization for efficient management of these expenses. It is noted that among the existing means of optimizing expenditures, the main ones are methods of constant expenditure management, such as control and accounting, planning, as well as a number of measures aimed at reduction of expenses. The utility of detailing expenditures and allocating rationalized costs from them has been substantiated. The problems that hinder the construction of a productive cost management system are noted.
Specifics of applying mechanisms of public-private partnership when selecting investment projects
Authors: Moiseenko Natalya
Published: November 2018

The article highlights the issues of selection of public-private partnership (PPP) projects, project ranking and recommended form and implementation scheme. Despite the fact that PPP approach is widely used all over the world, there is no unified classification of its forms, tools, models, types and methodology of adoption. The article lists the key points of selection of PPP projects and constraints, which arise during selection process. Specifics of implementation of different forms of PPP are described under condition of various factors. Prerequisites for the use of one of the form are presented. Several recommendations on project financing are given.
Influence of forced convection on the evaporation and internal dynamics inside of an array of salt solution droplets
Authors: Al-Rawi Omar , Wilson Mark
Published: November 2018

The effects of a gentle forced air convection on the internal dynamics of an array of multiple pinned sessile salt solution droplets are investigated via fully-coupled transient ALE finite element analysis. Results highlight the competition between the shear-induced circulation within the droplets and the gravity-driven flow in the droplets arising from increasing liquid density in regions of high water evaporation. At low air speeds, gravity effects dominate, resulting in a non-uniform concentration distribution. However, at higher speeds the shear-induced circulation within the droplets becomes sufficient to mix the liquid within the droplets via a 3D flow pattern, resulting in greater concentration uniformity. In addition, the shielding effect of leading droplets on downstream droplets is explored for various air speeds, with results showing differences in average concentration levels.
Heat transfer and flow field in a circular twisted channel
Authors: Bhattacharyya Suvanjan , Chattopadhyay Himadri , Banerjee Arnab , Benim Ali Cemal
Published: November 2018

In the present paper, along with experimental study, computational fluid dynamics analysis is performed, using the transition SST model which can predict the change of flow regime from laminar through transition to turbulent. The differential governing equations are discretized by the finite volume method. The investigations are conducted for Reynolds numbers ranging from 100 to 50,000 covering laminar, transitional and turbulent regimes, and for three length and three pitch ratios. The predictions are observed to show a good agreement with the measurements and published correlations of other authors. The analysis indicates that the large length ratio and small pitch ratio yields a higher heat transfer rate with relatively low performance penalty. The transition from laminar to turbulent regime is observed between Reynolds numbers of 2,500 to 3,500 for all cases. For almost all investigated cases the performance factors are greater than unity.
Natural convection melting of nano-enhanced phase change material in a cavity with finned copper profile
Authors: Bondareva Nadezhda , Sheremet Mikhail
Published: November 2018

Present study is devoted to numerical simulation of heat and mass transfer inside a cooper profile filled with paraffin enhanced with Al2O3 nanoparticles. This profile is heated by the heat-generating element of constant volumetric heat flux. Two-dimensional approximation of melting process is described by the Navier-Stokes equations in non-dimensional variables such as stream function, vorticity and temperature. The enthalpy formulation has been used for description of the heat transfer. The influence of volume fraction of nanoparticles and intensity of heat generation on melting process and natural convection in liquid phase has been studied.
Determination of distribution of heat-conducting material concentration in protective layer of TPS panel
Authors: Brodzik Łukasz , Frąckowiak Andrzej
Published: November 2018

Paper presents the problem of heating the damaged insulation of an orbiter. Changes of the insulation’s thermal properties, made by adding conductive material of high value of specific heat in a form of a dope to the protective layer, were examined. The analysis was made using insulating material LI900 and beryllium dope. In the paper was investigated the effect of the dopant’s share on the temperature distribution on the aluminum surface. This influence was depended on the size of the damage, defined by parameter D, as well as a constant percentage volume fraction.
Experimental and numerical studies of heat and mass transfer in low-temperature heat accumulator with phase transformations of accumulating material
Authors: Gorobets Valery , Antypov Ievgen , Trokhaniak Viktor , Bohdan Yurii
Published: November 2018

Accumulation of thermal energy is produced with the aim of storing at certain times, when there is an overabundance of this energy and its further use in other periods of time when there is a deficit thermal energy. Thermal energy storage may be carried out under heating of any material (water, solid materials etc.) or by using the phase or chemical transformation of the material (melting and crystallization processes, direct and reverse chemical reaction). Thermal accumulators with phase or chemical transformations are allowed to concentrate a large amount of energy in a relatively small volume of accumulating material. In this paper an experimental study and numerical modeling of heat and mass transfer in the heat accumulator during phase transformations of the accumulating material are presented. The experimental plant consists of a chamber filled with paraffin. In experimental studies, the changes of the temperature distribution in heat accumulating material and tube bundles have investigated. Numerical simulation of melting and solidification of heat accumulating material during the heated and cooled of tube bundles were performed. As the results of research, the basic laws of melting and crystallization processes in heat accumulator during phase transformations of heat accumulating material were determined.
On modeling of the initial stage of nonstationary nucleate boiling for the high heat fluxes
Authors: Levin Anatoliy , Khan Polina
Published: November 2018

During recent years, there have been made significant achievements in the numerical description of the bubble boiling, particularly, in the calculation of the bubble growth dynamics, the nucleation density, and the bubble boiling threshold [1, 2]. However, the numerical prediction is mostly based on the empirical correlations, the accuracy of which does not exceed 20%. Boiling is a complicated process, where each parameter affects not only the general outcome but other parameters, too. The non-stationary heat release is most difficult for modeling, because many of the existing researches are based on analytical expressions for the fluid temperature distribution. The basic stages of the explosive boiling are: (i) heating of the wall to the nucleation temperature; (ii) nucleation of the isolated bubbles; (iii) merging of bubbles and coverage of the entire surface by the steam phase; (iv) heating of the surface to the Leidenfrost temperature and transition to the boiling crisis. This paper presents results of the experimental study for the initial stages of the explosive boiling (i) and (ii), as well as an attempt to simulate them in order to clarify whether the existing approaches can be extended to the case of the nonstationary heat release.
Preliminary mathematical and numerical transient models of convective heating and drying of a brick
Authors: Łapka Piotr , Wasik Michał , Furmański Piotr , Seredyński Mirosław , Cieślikiewicz Łukasz , Pietrak Karol , Kubiś Michał , Wiśniewski Tomasz S. , Jaworski Maciej
Published: November 2018

The paper presents the initial approach to mathematical and numerical modelling and optimization of heat and mass transfer in elements of the masonry wall. The considered single moist brick is placed in the channel through which the dry air is flowing. Only one wall of the brick is in contact with the flowing air and through this boundary heat and moisture are exchanged. The non-equilibrium mathematical model is formulated for general case with three phases of moisture present in the porous building material, i.e., water vapour in the moist air filling the pores, liquid water (bound water) adsorbed at the surface of the solid component of the material and free liquid water either in a discontinuous form (funicular) or continuous one (pendular). However, at this stage of development of the numerical model the moisture in the form of motionless liquid water and water vapour which reside in the ceramic material are considered. Moreover, the moisture and heat diffusion in the porous hydroscopic material of the brick as well as moisture and heat convection in the flowing air are assumed. The numerical model is developed with the aid of the commercial software ANSYS Fluent and its advanced customisation functionalities like the User-Defined Function, User-Defined Scalar and User-Defined Memory. Subsequently, investigation of the influence of the mass transfer coefficient between the free liquid water and moist air in the porous building material are carried out.
Heat transfer coefficient determination using the FEM with time-dependent Trefftz-type basis functions in subcooled flow boiling in a minichannel
Authors: Maciejewska Beata , Piasecka Magdalena
Published: November 2018

Results concerning flow boiling heat transfer in a vertical minichannel of 1.7 mm depth were shown. The channel was asymmetrically heated by a thin foil. Its surface temperature was recorded continuously in points by thermocouples. Measurements were carried out in 0.01 s intervals. The objective of the numerical calculations was to determine the heat transfer coefficient on the heated foil–fluid contact surface in the minichannel from the Robin boundary condition. Both the foil and fluid temperatures were the result of solving the nonstationary two-dimensional problem in the foil and flowing fluid. The problem was solved by using the FEM combined with Trefftz-type basis functions. The values of the time-dependent local heat transfer coefficient were presented and discussed.
Natural convection in a rotating cavity partially filled with a porous medium under the effect of a local heater
Authors: Mikhailenko Stepan , Sheremet Mikhail
Published: November 2018

The combined effect of uniform rotation and porous layer on natural convective heat transfer in a square cavity with a local heater has been studied numerically. The local thermal equilibrium model with the Brinkman-extended Darcy law has been used for description of the heat transfer and fluid flow within the porous layer. Governing equations with corresponding boundary conditions formulated using the non-dimensional stream function and vorticity variables have been solved by the finite difference method. The effects of Taylor number and porous layer thickness on fluid flow and heat transfer have been examined. It has been found a non-linear effect of the porous layer thickness on the heat transfer rate.
Comparison of predictive methods for flow boiling heat transfer in conventional channels and minichannels – the effect of reduced pressure
Authors: Mikielewicz Dariusz , Jakubowska Blanka
Published: November 2018

In the paper are presented the results of follow on studies from [1]–[3] using authors own model to predict heat transfer coefficient during flow boiling. The model has been tested against a large selection of experimental data collected from various researchers to investigate the sensitivity of the in-house developed model. The collected experimental data came from various studies from literature and were conducted for the full range of quality variation and a wide range of mass velocity and saturation temperatures. In the work are presented the results of calculations obtained using the in-house developed semi empirical model on selected experimental flow boiling data of the refrigerants: R134a, R1234yf, R600a, R290, NH3, CO2, R236fa, R245fa, R152a and HFE7000. In the present study the particular attention was focused on the influence of reduced pressure on the predictions of the theoretical model. The results of calculations were to test the sensitivity of the flow boiling model with respect to selection of the appropriate two-phase flow multiplier, which is one of the distinctive elements of the in-house model. The main purpose of this paper however is to show the effect of the reduced pressure on the predictions of heat transfer during flow boiling.
Leidenfrost evaporation of water droplet
Authors: Orzechowski Tadeusz
Published: November 2018

The present paper examines the behaviour of a single large droplet levitating over a hot surface, unsteady mass of the droplet, and heat transfer. It was assumed that the evaporation from the upper surface of the droplet is negligibly small compared with the amount discharged from its lower surface, and the heat transfer coefficient is the power function of droplet orthogonal projection onto the heating surface. Based on the photographic documentation, the dependence of the droplet projection on time was approximated. A heat balance was written in the form of a non-linear first order differential equation. The solution to the equation was included. The analytical function of droplet mass change in time was used to determine the exponent of the power dependence of the heat transfer coefficient on the orthogonal droplet projection onto the heating surface. The comparison showed the method proposed in the study could be applied to analyse the behaviour of a water drop levitating above a surface at the temperature higher than the Leidenfrost point.
Assessment of gas permeability through porous skeletal media with anisotropic internal structure
Authors: Wałowski Grzegorz , Filipczak Gabriel
Published: November 2018

The results of experimental studies in the field of gas permeability of porous materials referring to gas flow have been shown. Coal chars with anisotropic porous-slotted structure have been tested. The studies have been carried out on a special test bench that allows for the measurement of gas permeability in terms of three flow orientations related to symmetrical specimens in the cubic form. The results of the measurements indicate that there is a considerable effect of the flow directivity on the permeability of carbonizers, which results from their integral anisotropic structure. A permeability coefficient for such materials has been defined and the experimental assessment of the value of this coefficient against gas flow and the total pressure drop on a porous medium has been made. The usefulness of computation methods characterising the hydrodynamics of gas flow through porous materials has been made, and the possibility of a numerical mapping of the flow geometry of solid materials with tortuous structure has been indicated.
Air flow characteristics of a room with air vortex diffuser
Authors: Borowski Marek , Jaszczur Marek , Satoła Daniel , Karch Michał
Published: November 2018

The air diffuser is a very important component of any ventilation system, and the comfort level of ventilated space occupants depend among many other factors on properly designed and choice of diffusers. At present a large number of diffusers are produced to meet a different kind of requirements. One of the most efficient and very popular types of the diffuser is the vortex diffuser in which air flow has angular as well as translational velocity components. This paper investigates experimentally airflow characteristics of vortex ceiling diffuser and its effect on airflow in a ventilated space. Two thermal comfort criteria namely: mean age of the air and ventilation effectiveness have been used to predict the comfort zone inside the room. Effect of supply air velocity on the flow field is investigated and hence the on comfort and energy consumption. The results show that significant amount of energy can be saved by using vortex diffuser in reference to the other diffusers type. The values of the velocity decay coefficient were compared for different diameters of vortex diffuser.