Thermophysical characteristics of gas-power dual-fuel engines w12v50 df for liquefied gas shipping vessels

Maritime transport plays important role in the economic development of society – 90% of goods are transported by ships. At the same time, maritime transport requires a significant amount of fuel resources. Production of liquefied natural gas (LNG) is becoming the fastest growing industry in the modern global energy sector. Today, LNG accounts for 40% of the physical volume of world gas trade, and its share will increase up to 60% by 2040. Currently, natural gas is used on ships in the form of liquefied petroleum gas, compressed natural gas, and liquefied natural gas (LNG). The article deals with the urgent problem of operation of dual-fuel diesel-electric installations of ships. The need to study the heat-engineering parameters of two-fuel diesel generators of the Wartsila company has been substantiated. The authors present the dependencies of main heat-engineering parameters on the load of Wartsila W12V50DF dual-fuel engines used as a generator drive in the main electric propulsion engines on LNG tankers. A comparative assessment of the dependencies of exhaust gas temperature, turbocharger rotation speed, boost pressure and gas pressure on the load of diesel generators on two LNG tankers has been carried out. The article analyzes the presented dependencies. The authors substantiate the need for further improvement of their design and workflow.

EFFICIENCY OF THE NOZZLES OF CONTACT HEAT EXCHANGERS

At powerful thermal power plants or boiler houses, the efficiency depends to the greatest extent on the amount of heat lost with the cooling of turbine condensers, exhaust gases that have a high temperature. Each type of such losses is a large unused energy potential, that is, a secondary energy resource that can be used. At the same time, the use of secondary resources and industrial emissions will improve the ecological situation in the regions, and this has always been an urgent task. As a rule, large losses of thermal secondary energy resources in boilers are reduced by installing economizers and air heaters. Contact types of heat exchangers are distinguished by the best efficiency in operation. In contact economizers, to increase the surface of heat and mass transfer, it is advisable to use various types of nozzles. The aim of the study is to develop such an indicator, with which it is possible to determine the optimal type of nozzle of the contact economizer installed after the steam boiler. This indicator should show the highest heat engineering efficiency of the packing with a small hydraulic resistance of the heat exchanger. By using the coefficient of specific energy efficiency of the packing in the heat exchanger of waste gases of heating equipment, it is possible to analyze the work of the packing space from the standpoint of thermal and hydraulic efficiency and select the optimal type of packing for each individual unit or installation. Geometric parameters determine the required volume of the apparatus and the hydraulic resistance of the exhaust gases movement. The hydraulic resistance affects the consumption of electrical energy for the drive of smoke exhausters for sucking off exhaust gases from heat engineering installations through the free section of the heat exchanger. Taking into account the developed indicator of the specific energy efficiency in waste heat utilizers, it is possible to select such a type of packing, at which the optimal level of waste heat utilization will be achieved.

HEAT ENGINEERING FEATURES OF TRANSPARENT FENCING STRUCTURES OF BUILDINGS

The use of glass fencing structures - panoramic windows in the residential segment of modern city development is investigated. The peculiarities of the use of panoramic windows in the residential segment of the region are determined. An analysis of scientific publications in magazines with the impact - a factor and the approaches to increasing the energy efficiency of the thermal insulation shell of the building with glass elements of the facade are determined. The advantages and disadvantages of the use of panoramic windows in terms of heat engineering properties of a fencing structure are outlined. It is determined that according to the normative method of calculating the given thermal resistance, there may be a significant difference in calculating the entire facade and design for one room. To confirm the comparative calculation, which resulted in the resulting thermal resistance for a fragment of the facade (where there are two windows) is 3,3 m2 K / W (corresponding to the requirements of the normative value), and when calculating the fragment of this facade of a separate room with a panoramic window with a panoramic window. The result of the given thermal resistance is 2,6 m2 K / W (which is significantly lower than the normative value). The factors influencing the technical state of panoramic windows are outlined and lead to a decrease in the heat-insulating characteristics of the enclosing structures of the building; As well as measures and organizational and technical solutions, which allows the use of panoramic windows in modern housing construction. It is proposed for the heating of premises with panoramic windows of the scheme of placement of heating systems, namely: installation of vertical radiators on the side of the double-glazed windows; Planting a convector-type floor battery; arrangement of the system "Warm floor" and combined systems; internally floor convectors; infrared heaters; Installing slit or plinth convectors in the floor below the window, on the wall or ceiling. Recommended investors of new apartments to pay attention not only to the facade of the facade in the design decisions of external enclosures of buildings with the use of panoramic windows, as well as technical solutions of windows, ventilation and heating systems, which significantly affect the energy efficiency of the future apartment.

«CADRES DETERMINE EVERYTHING». TO THE QUESTION OF THE REASONS FOR THE FAILURE OF THE VOLGA SHALE PROJECT DURING THE PRE-WAR FIVE-YEAR PLANS

The author examines the activities of managers of shale ores and heads of party bodies of the Kuibyshev and Saratov regions who implemented the Volga shale project in the 1930s. The managers from mining departments committed a number of unprofessional actions in the organization of the production process of shale mining, which contributed to the departure of workers from the mines, mass absenteeism, downtime of teams of miners during work shifts. The party leaders of the Kuibyshev and Saratov regions did not provide the necessary assistance to engineers from the Volga Heat Engineering Institute in organizing tests of shale furnaces and paid little attention to the problems of shale mines.

Heat Engineering Heterogeneity Of The Outer Walls Of Earthquake-Resistant Buildings

When assessing the level of energy efficiency of civilian buildings, a special place is given to establishing the level of thermal protection of their external enclosing structures. Significant discrepancies in the results of theoretical and experimental studies of heat fluxes through the outer walls of buildings erected in seismic areas are associated with the design features of fences - the presence of reinforced concrete elements in them: anti-seismic belts at the level of floors, cores at intersections of walls and along the edges of large window openings ... In addition, in recent years, external walls have become widespread, which are filling of bricks or aerated concrete blocks between the main structural elements of the frame - monolithic reinforced concrete columns and crossbars. The introduction of reinforced concrete elements into the structure of the external wall fencing provides strength, rigidity and stability of buildings, guarantees its seismic resistance. At the same time, reinforced concrete inclusions are significant “cold bridges” in warmer brick or aerated concrete masonry. Such heat engineering heterogeneity of earthquake-resistant outer walls significantly complicates the process of determining their heat-shielding properties. This, in turn, leads to errors in the design of heating systems, which inevitably affects the thermal comfort of the premises, the formation of condensation and mold zones in the cold zones of the inner surface of the fences. The article presents the results of theoretical and experimental studies to determine the heat-shielding properties of external heat-engineering heterogeneous walls of earthquake-resistant buildings. The most reliable method for calculating the reduced resistance to heat transfer of an inhomogeneous external structure and the coefficient of its thermal inhomogeneity have been established.

Experimental detection of mechanical efficiency of marine diesel engines

The article summarizes the results of heat engineering tests of diesels used in the educational process of Volga State University of Water Transport and its branches. Although the test goals were different in each case, the indicator diagrams of the working process in each cylinder were recorded in the course of the tests. Analysis of indicator diagrams helped to determine the indicator power of the engine in each case. By comparing the indicator parameters with the corresponding effective ones there was performed the estimation of the mechanical efficiency of each engine at different speeds of rotation of the crankshaft. The studies were carried out on engines of brands 6NVD48AU, 6L275RrII/PN, 8NVD36U, 6L160PNS. It was found that in almost all cases, mechanical losses included fan losses in load devices and friction losses in their bearings. The concept of a screw characteristic is considered. A graph of the propeller characteristics in relative units for various types of engines is built. It is noted that it is very difficult to set a specific value of the crankshaft speed required for testing, the actual points will be close to the theoretical ones, shifting along the helical characteristic. An algorithm for testing and processing the results is presented. There have been analyzed the dependences covered in literature (analytical and statistical) for determining the mechanical efficiency.

SIMULATION OF THE RADIANT HEAT TRANSFER PROCESS IN THE ELEMENTS OF ROASTING EQUIPMENT

The object of the research is the process of radiation heat transfer, taking into account a single reflection of rays in the IR device of food production. Investigated problem – the work is devoted to solving the problem of irregularity of radiation heat transfer during infrared roasting of food products. Main scientific results. The inverse problem of heat transfer by radiation has been solved and a technique has been developed for determining the profiles of the ray flux reflectors for uniform irradiation of receivers of a convex section. Analytical modeling of all-round uniform irradiation of an elliptical receiver has been carried out. An experimental device with low-inertia temperature sensors for infrared roasting of semi-finished meat products has been developed, which makes it possible to use a reflector shaped according to the developed analytical technique. The verification of the created technique for determining the profiles of reflectors by means of a computer experiment using the TracePro and Mathcad software systems has been carried out. The area of practical use of the research results: the use of an experimental device with a radiant flux reflector for roasting semi-finished meat products proves that the obtained technique for profiling reflectors of heat engineering systems is acceptable for the design of infrared equipment for food production and restaurant facilities. This technique allows simulating the profile of the radiant flux reflector depending on the shape of the receiver. Studies have shown that the use of a profiled reflector in the experimental device reduces the duration of roasting of natural portioned semi-finished beef products by 33 %. Innovative technological product: a technique for determining the profiles of ray flux reflectors for uniform irradiation of receivers with a convex section. Device for infrared roasting of semi-finished meat products. Scope of application of an innovative technological product. The study of an experimental device with a designed radiant flux reflector for roasting semi-finished meat products proves that the obtained technique for profiling reflectors of heat engineering systems is acceptable for the design of infrared equipment for food production and restaurant facilities. Using this approach allows to approach the solution of the problem of irregularity of irradiation of products during infrared roasting

Study of the Composite Materials Optimal Structure Containing a Hollow Aluminum and Silica Microsphere Dependence on Humidity

Aims:: The main goals of this research are exploration of energy-efficient building materials when replacing natural materials with industrial waste and development of the theory and practice of obtaining light and ultra-light gravel materials based on mineral binders and waste dump ash and slag mixtures of hydraulic removal. Background.: Experimental data on the conditions of formation of gravel materials containing hollow aluminum and silica microsphere with opportunity of receipt of optimum structure and properties depending on humidity with the using of various binders are presented in this article. This article dwells on the scientific study of opportunity physical-mechanical properties of composite materials optimization are considered. Objective.: Composite material contains hollow aluminum and silica microsphere. Method.: The study is based on the application of the method of separation of power and heat engineering functions. The method is based on the use of the factor structure optimality, which takes into account the primary and secondary stress fields of the structural gravel material. This indicates the possibility of obtaining gravel material with the most uniform distribution of nano - and microparticles in the gravel material and the formation of stable matrices with minimization of stress concentrations. Experiments show that the thickness of the cement shell, which performs power functions, is directly related to the size of the raw granules. At the same time, the thickness of the cement crust, regardless of the type of binder, with increasing moisture content has a higher rate of formation for granules of larger diameter. Results.: The conditions for the formation of gravel composite materials containing a hollow aluminosilicate microsphere are studied. The optimal structure and properties of the gravel composite material were obtained. The dependence of the strength function on humidity and the type of binder has been investigated. The optimal size and shape of binary form of gravel material containing a hollow aluminosilicate microsphere with a minimum thickness of a cement shell and a maximum strength function was obtained. Conclusion.: Received structure allows to separate power and heat engineering functions in material and to minimize the content of the excited environment centers.