Vol 20, No 1 (2019)
- Year: 2019
- Articles: 11
- URL: https://journals.rudn.ru/engineering-researches/issue/view/1202
- DOI: https://doi.org/10.22363/2312-8143-2019-20-1
Full Issue
Aviation and rocket and space technology
Experimental studies of the performance of the heat-shielding layer of composite pipelines during cooling with liquid hydrogen
Abstract
The development of technology for aircraft and rocket engines more efficient and environmentally friendly cryogenic fuels in the form of liquefied gases: hydrogen (vinyl), oxygen (oxide), natural gas (methane), required the creation of pipelines from modern composite materials, as well as new thermal insulation coatings (TIC), providing reliable protection of these highways from external heat leakage. Fuel out-of-flight manifolds of reusable aircraft require a particularly reliable TIC, since during the operation of the product, their multi-cycle cooling down occurs when pouring cryogenic fuel into the pipelines and heating at the discharge. Thermally insulating coatings in the form of polyurethane foam (PUF), applied to the surface of the protected product, by spraying or pouring a mixture of the constituent components, which are widely used at the present time, are not fully suitable for cryogenic pipelines due to the deterioration of their heat insulating properties in the process of cyclic cooling. The aim of the work is to create a new design and technological solution that ensures the performance of the TIC in the conditions of high-cycle thermal loading. In connection with the prospect of using cryogenic fuels in an aviation (reusable) technology, ensuring the performance of a TIC in such conditions is relevant. For the developed technology, experimental determination of the main parameters of the TIC was carried out. Composite pipelines of curvilinear and rectilinear shape were used as objects of research. The pipeline design included a sealing film sheath, a power sheath made of a polymer composite material, a foam heat insulating coating and metal connecting flanges. On model composite samples of cryogenic pipelines, cyclic tests for cooling with liquid hydrogen (filling of fuel lines) and heating to ambient temperature (draining components) were carried out. During the tests, the pipeline was first cooled with hydrogen gas for one hour. Then, for one hour, liquid hydrogen was poured into the internal cavity, after which natural warming up to a normal temperature was carried out for an hour. The obtained results allowed to determine the dependence of temperature and heat flow of the shell with TIC on the number of cooling cycles, to propose a design and technological solution for a significant reduction of the cryopump at large temperature differences in the TIC, to show the effectiveness of cyclic cooling of foam porosity with closed porosity of the “Vikort-3M”
7-13
Mechanical engineering and machine science
Influence of temperatures of a low-potential source and heat consumer on the efficiency of a heat pump
Abstract
The article describes the experimental setup for testing a heat pump and the results of its operation at various temperatures at its inlet and outlet. An actually task is to study the operation of a heat pump under various boundary conditions, which are determined from the phase transition temperature in the evaporator and condenser. These temperatures depend on the temperature in the evaporator of a low-potential source of heat (the lower source is water, air, etc.) and the temperature in the condenser of a high-potential source of heat (the upper source is a consumer). The main indicator of the efficiency of the heat pump is the coefficient of performance. To determine the reliable value of the coefficient of performance, tests of compression heat pump were carried out. Refrigerant R-142b was used as a working fluid. Based on the experimental data, the dependences of the coefficient of performance on the temperature of the hot and cold heat source are constructed. Also, the coefficient of performance heat pump decreases when the lower heat source decreases.
14-19
Application of the universal ultrasonic reactor in the processing of rare earth metal ores concentrates
Abstract
In recent years, heavy industry has rapidly increased interest in rare earth metals (REE). At the same time, new tasks on completeness of extraction and quality (purity) of REE are set. Providing new requirements for the quality of rare-earth metals can be achieved by two modern methods of ore processing. The first method is traditional leaching, but with the use of modern ultrasonic reactors of a through passage type of domestic production. The second method is leaching with the use of expensive imported impregnated sorbents that require special disposal after the deposition process of the desired fraction of material. The disadvantage of ultrasonic devices for processing of rare-earth metals is that the assigned parameters of the working chamber (length and diameter) are calculated for a specific type of ore being processed. Therefore, ultrasonic reactors operating in the metallurgical industry cannot be used to process all types of REE ores. The aim of the work is to study the efficiency of processing concentrates of ores containing rare earth elements by leaching using a universal ultrasonic reactor suitable for processing various concentrates containing rare earth elements. In this work, alkaline ore processing is carried out in an ultrasonic reactor of a special design, which allows regulation of the dimensions of the reactor working space this makes it possible to configure the reactor for highly efficient ore processing at different initial concentrations of valuable components. As shown by the results of the experiments, the extraction of rareearth metals and other valuable components of the ore in the ultrasonic reactor of this design is not less than 98.3%.
20-27
Earth science
Improving the efficiency of urban underground structures as objects of civil defense
Abstract
The rapid development of cities, as well as the growing number of natural and man-made disasters, makes it important to place part of various urban buildings underground, as well as design the operation of these facilities in emergency situations. The article is devoted to the study of the possibility of using urban underground structures as protective objects in the mountainous regions of Russia (using the example of Primorsky Krai). It was proved that for successful development of underground space and implementation of existing projects, an appropriate urban planning program should be developed, which would link socio-economic issues with architectural planning and engineering and technical measures, and such a program is necessary at the stage of engineering development of new territories or during reconstruction plots of old buildings. The technological parameters of the efficiency of dual-purpose underground structures are revealed. Capacity, volume of the structure and the required volume of air were taken as decisive parameters in the design of such a structure. The obtained mathematical dependences of the volume of the underground structure on the number of people being sheltered and the necessary ventilation on the capacity allow to interpolate and extrapolate, obtaining the necessary parameters of the technological efficiency of using urban underground structures as dual-use objects.
28-36
Upper Cretaceous rhyolitic ashes in the Utes Derevyannykh Gor area (Novaya Sibir Island, the New Siberian Islands)
Abstract
The article is concerned with the first finds of rhyolite ashes in Upper Cretaceous sediments of Novaya Sibir Island. In the course of the field work in the area of cape Utes Derevyannykh Gor in 2016, four layers of unlithified fine-grained ashes were found in the Turonian-Coniacian coal-bearing Derevyannye Gory Formation. The article presents the results of petrographic, X-ray diffractometric and microprobe analysis of pyroclastics from ash layers. A typification of volcanogenic-terrigenous deposits is proposed. Thin section of the samples were investigated on a polarizing microscope. X-ray phase analysis of the clay fraction was carried out using a DRON-3 diffractometer. X-ray microanalysis of vitroclasts were carried out on a scanning electron microscope “Jeol JSM-6480LV” with the microprobe analyzer “Oxford Instruments INCA-Energy 350”. It was established that Derevyannye Gory Formation is composed of rhyolitic tuffites, among which fine-grained crystal-vitroclastic and vitroclastic ashes of low and normal alkaline high-potassium rhyolites with thickness up to 2.5 m. Low pyroclastics sediments are not widespread. New data on the structure and composition of the Derevyannye Gory Formation confirm the hypothesis of previous researchers, that sedimentation in the Late Cretaceous in the area of Novaya Sibir Island was accompanied by explosive acidic volcanism. The main purpose of the article is to discuss the sources of pyroclastic material for the territory of the New Siberian Islands in the Turonian-Coniacian age. The conclusion is made about the territorial proximity of the paleovolcanic eruption center to the area of sedimentation. It is assumed that the paleovolcanic centers were located within the present territory of Kotelny, Zemlya Bunge, Faddeevsky islands and, probably, were inherited from the Early Albian stage.
37-47
Current state of knowledge on the problem of water objects’ frozen watersides destruction
Abstract
Due to the fact that the vast territory of Russia is located in the zone of permafrost, there is an urgent need to study coastal erosion, taking place not only during the construction cycle, but also during the subsequent operation of commissioned facilities, in particular hydrotechnical ones. The analysis of recent papers of foreign and domestic researchers who work in the field of knowledge of water objects’ frozen coasts destruction was made. The influence of the energy of a moving water flow on the reformation of the coastal slope and on the stability of river channels as a whole was considered. Analysis of the results of mathematical and laboratory modeling showed that the channel deformations of the rivers flowing in the cryolithozone differ significantly from the deformations of the channels laid in soils which are not affected by the water-ice phase transition. The causes of the erosion of the frozen shores in the under permafrost conditions are not only mechanical, but also thermic components during the movement of water, which indicates the instability of the permafrost as a solid. All this should be considered when designing hydraulic engineering objects.
48-56
Lithological features of stratigraphy and tectonic zoning of seismically active Zagros regional trough within the waters of the Persian Gulf
Abstract
The article discusses some features of the stratigraphy and the main points of the tectonic characteristics of the Zagros (Mesopotamian) regional deflection due to its seismic activity and oil and gas potential. The stratigraphy within the whole Pre-Zagrosky regional trough, despite its length, is similar in different parts, the main differences are related to the tectonic structure. The formation of the folds was mainly influenced by tectonic movements during the formation of alpine folding. A significant amount of work was carried out on the basis of the comprehensive analysis of the NEIC earthquake catalogs (The National Earthquake Information Center), formed by the United States Geological Survey. Ideas about the structure of the region under consideration were carried out on the basis of a study of literary sources, as well as the integration of data from previous author studies. Comparison of data on earthquakes that occurred in the period 2005-2017 and the reconstruction of the tectonic development of the region under consideration helped to establish links between earthquakes and tectonically active zones, and ultimately, determine the seismic hazard of different parts of the Persian Gulf. The article shows the main tectonic causes of earthquakes. The article has practical importance in predicting future natural phenomena and the position of their foci, as well as in determining the causes of events that have already occurred.
57-65
Application of remote sensing for monitoring of flood areas
Abstract
Traditional measurement techniques “in situ” sometimes fail to magnify the spatial distribution of floods. For these cases, the remote sensors provide methodologies of very low economic cost and high reliability when mapping flooded areas and quantifying the damages. Due to the dynamic nature of these phenomena, it is necessary to use satellite images of high temporal resolution, however this type of images usually have a low spatial resolution. In relation to this problem, traditional classification techniques are not reliable enough for flood delineation and monitoring since they use “hard methods” of classification, where the coarse pixel is assigned a single type of coverage. On the other hand, “smoothed methods” have the ability to assign different kinds of coverage to the interior of the thick pixel. The present investigation makes the application of a sub-pixel analysis methodology (sub-pixel analysis - SA) for the monitoring of flooded areas. The improvement of the delimitation is achieved with the use of topographic attributes provided by a digital terrain model (DTM). The methodology was applied to the monitoring in the Great Depression Momposina, specifically to delineate the swamp of Zapatosa.
66-78
Ways to assess of seismicity of the territory of Syria
Abstract
The article considers estimates of changes in the magnitudes of seismic events for two years (2005-2006) according to seismic catalogs. For this period, graphs of the law of repeatability of earthquakes were constructed and compared with each other. The analysis of the graphs of the frequency of occurrence of a number of zones built during seismic zoning was carried out, and the relationship between parameter A and the earthquake source mechanism was determined. Seismic zoning - the division of the territory into areas with varying degrees of intensity occurred and expected earthquakes. Seismic zoning data is used in the design and construction of earthquake-resistant structures and solving other practical problems in a seismically dangerous area. This is the applied aspect of seismic zoning. For the mapping of seismic zoning, historical data and instrumental observations of earthquakes, geological-tectonic and geophysical maps, as well as data on the movements of blocks of the earth’s crustare used. There are areas of possible occurrence of earthquake foci (OEF zones) with different depths. The greatest danger is represented by earthquakes with foci within the earth’s crust (at a depth of 3 to 30-50 km). The article provides a statistical analysis of the earthquakes of Syria for two years, taking into account historical earthquakes from the chronicles. The result of the work is the establishment of links between the identified earthquakes and the planetary events of the Earth, including solar activity. There is an increase in seismic activity in winter. Presented research should be used in forecasting future. It is worth noting that the basis for forecasting future natural events is the integration of analytical methods for analyzing data and theoretical ideas about the tectonics of the region in question.
79-84
Influence of speed distribution in a rounded flow on the character of slopes erosion
Abstract
One of the most important issues of river hydraulics is the movement of water and the formation of a channel in a stream that has a non-straight-line outline in the plan. Under natural conditions for rivers characteristic winding shape in the plan. The curvature of the jet occurs when the flow is divided into sleeves, at the inflow into the river, the confluence of flows, etc. Therefore, the study of channel processes in rivers is impossible without knowledge of the flow patterns at the curve of the channel. When designing hydraulic structures, including bridge crossings on the meandering sections of rivers, one should know the features of the dynamics of the channel in the sections of the flow turning. In winter, such areas may be narrowed due to the freezing of the channel, and during the period of ice thawing they are clogged with ice fragments. The narrowing of the canal causes an increase in the Reynolds number and a redistribution of velocity diagrams in the area under consideration, which causes a change in the erosion pattern. In laboratory conditions, the nature of the distribution of velocities and the formation of vortices on the installation, creating a rounded flow. It is shown that, at critical Reynolds numbers, a vortex countercurrent occurs in the rounded flow at the inner shore. The impact of this velocity distribution on the erosion pattern of the various slopes of the rounded flow was analyzed.
85-95
Standard models for exploration and development complex copper-porphyry deposits in the Far East of the Russian Federation
Abstract
The article deals with the prospects of development of copper-porphyry deposits discovered within the largest ore occurrences and prospecting areas of the Russian Far East. Revaluation of large reserves of copper with associated elements account (gold, silver, molybdenum) on geological data based increases the economic justification for the development of already discovered deposits, as well as the continuation of exploration work on the identified ore occurrences. Geological exploration in a certain sequence necessitates the preparation of complex prospecting, appraisal and multifactor models for the development of large copperporphyry deposits in the Far Eastern region of the Russian Federation. Complex models of geological objects for prospecting and searches of complex copper-porphyry deposits are formed in relation to each geological and industrial type. In the article, authors offer exploration typical models to develop of complex copper-porphyry deposits at different stages of geological survey. The models show the features of the deep structure of the geological objects of the simulated class and the main features of their ore-metasomatic and geochemical zoning, as well as trends in the composition and physical properties of ore-controlling geological bodies with depth. Authors present the theoretical basis of prospecting and appraisal features, reflecting the patterns of manifestation of the studied ore-bearing areas in the Far East, Russia, leads the analysis the complex of geological and geophysical studies of the deep structure of copper-porphyry deposits, formulates methodical approaches for develop modelling of copper-porphyry type fields to increase an efficiency of a geological and economic assessment of these geological objects. These approaches make it possible to comprehensively assess the parameters of exploration and development of deposits, taking into account the export-oriented orientation and investment attractiveness of the Far Eastern region of Russia.
96-104