Технические науки. Рубрика в журнале - Бюллетень науки и практики
Project of building: solar hot water
Статья научная
The rapid development of urbanization in China has led to an increase in high-rise residential buildings, leading to a surge in the construction industry. However, this prosperity has brought about a significant increase in energy consumption, prompting people's demand for alternative energy. As a solution to this problem, solar hot water systems are becoming increasingly popular in China. The following contents need to be considered in the design of solar hot water systems. The general solar hot water system consists of solar collectors, solar water distribution pipes and water storage tanks. The arrangement of the water storage tank and the water distribution pipe is matched with the design of the building, which has great influence on the operation of the solar energy in the building. With the rapid increase in building height and the increase in residents, the roof area has not changed. The architectural layout will have an impact on the absorption performance of solar radiation. Therefore, in order to optimize the use of solar energy, regional planning should be considered. Different solar radiant intensity and different locations of solar collectors will lead to different collection efficiency and hot water supply conditions of solar water heating systems. Throughout the entire process of architectural design, the application of solar energy technology in buildings also requires consideration of the operating area conditions and architectural style, in harmony with the architectural style.
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Статья научная
Among the alternative energy sources, of particular importance is hydrogen energy, which is likely to address the acute environmental problem of large cities in the near future, in terms of pollution of the environment, first of all, of air pollution from vehicles. Among hydrogen-containing raw materials, which can be used in a fuel component, hydrogen sulphide is of particular importance. It is well-known that the Black Sea the largest basin on the planet by the amounts of hydrogen sulphide dissolved in water. In that regard, the Black Sea is the object of the attention of scientists, since its deep waters contain hydrogen sulphide, hydrosuphide and suphide ions in large quantities. The sources of their origin are gases erupted from the volcanic and geological splits existing at the bottom of the sea, as well as organic substances and products of decomposition of microorganisms brought down by the rivers. In this regard, the Black sea may become a potential source of hydrogen energy, and simultaneously that may improve environmental situation in the Black Sea. The paper analyzes the challenges existing in the use of hydrogen obtained from hydrogen sulphide of the Black Sea, as an alternative fuel in the internal combustion engines of vehicles, as well as the prospects for addressing these challenges.
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Prospects of soft fresh cheese production in Kazakhstan
Статья научная
In this article, the relevance of increasing the production of cheeses on the domestic market of the Republic of Kazakhstan is shown. In accordance with changes in the structure of the population’s nutrition and protein deficit, increasing attention is being paid to increasing the use of protein resources for food purposes, including the creation of new products. According to the Food and Agriculture Organization of the United Nations, the volume of world cheese production is constantly increasing. When polling the population in recent years it became clear that the cheese-curd market is waiting for the local producer. Therefore, the concept of development of low-cost cheeses remains to be topical - with high yield and accelerated maturation periods, which will be analogues of import-brand brands. The advantages of organizing the production of soft fresh cream cheese and cheese products of this type for domestic cheesemakers lie on the surface: this is a relatively new product for our market, soft cheeses have an extremely high yield, which makes their products very cost-effective, and this kind of cheese now has steady and constantly growing demand. The difference between fresh soft cheeses is that they are not pressed in production, the dairy raw material is gentle heat treatment, thanks to which useful substances remain intact in cheese. Proceeding from this, it can be concluded that the innovations and increase in the production of soft fresh cheese are real and possible and necessary.
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Pulsating enhanced heat transfer
Статья научная
The paper mainly introduces the mechanism of turbulent fluid heat transfer enhancement and the factors affecting heat transfer. The physical parameters of pulsating fluid mainly include pulsation frequency and amplitude. The factors affecting heat transfer are the physical properties of the pulsating fluid and the installation of a pulsation generator. The position, the type of pulsation occurrence, the natural frequency of the heat exchange system, etc.; the methods for strengthening the pulsating heat transfer characteristics mainly include disturbing flow elements, changing the size of the flow channel structure, compound heat transfer enhancement, and setting the induction vibration device in the flow channel.
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Removal of Damaged Pipes During Major Repairs of Oil and Gas Wells
Статья научная
The relevance is determined by the need to solve a number of scientific, practical, and engineering problems related to fishing operations during well workovers. The article provides information on some cases where it is necessary to repeat the operation after completing the fishing work, which should be performed with the lowest possible force parameters and process adjustments. As a result of non-compliance with these requirements, as well as defects formed in the lifting pipes (holes, cracks, wall thickness reduction) due to long-term well operation, the use of standard pipe catchers during emergency operations is further increased. Frequently encountered deformed emergency ends of complex configuration are classified. A classic method for correcting deformed ends is noted, consisting of milling with bottomhole and ring milling cutters and other auxiliary catchers, which can complicate the well situation. The aim of the work is to improve the quality of fishing operations, speed up the extraction of emergency lift pipes with deformed ends of complex configuration, and prevent complications during their extraction from the well. This goal is achieved by implementing an innovative, improved method and design of standard fishing tools adapted to well conditions. The use of the developed straightening and fishing tool-a combined bell consisting of a through bell located at the bottom, which does not function as intended but bends, crushes, and collects the deformed ends in the center, achieving a cylindrical shape and deepening the end of the pipe inward, and a bell located at the top-allows for the removal of the pipe in a single operation by cutting the thread and then screwing onto it. The use of this tool eliminates multi-step operations to correct deformed ends. Depending on the internal diameter of the column and the type and size of the pipes to be extracted, as well as the clamped and sequentially extracted emergency pipes of the first and second rows of lifts with normal emergency ends, by changing the component elements and installing the required number, it is possible to reliably grip and extract them from the well.
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Research of acoustically improved Helmholtz resonator
Статья научная
The three-dimensional acoustic finite element method is used to predict the transmission loss of the Helmholtz resonance muffler. The results are in good agreement with the experimental results, indicating the applicability and accuracy of the numerical method used in this paper. On the one hand, in order to reduce the resonance frequency without changing the shape of the resonator, the connecting tube is extended to the inside of the resonator, and the influence of the extension length and the cross section shape of the extension tube on the acoustic characteristics of the resonator is discussed in detail. On the other hand, in order to broaden the muffled frequency band of the traditional Helmholtz resonators, the resonators are combined in series and parallel, and the influence of the combined structure on the acoustic characteristics is discussed in detail.
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Статья научная
The ship’s central cooling water system is one of the most important systems serving the main engine. With the progress of society, the design and construction of ships increasingly need to develop in the direction of environmental protection and energy-saving. Taking the 59,990 t bulk carrier as the research object , this paper proposes that based on the frequency conversion control of the seawater pump and supplemented by the energy-saving scheme of pulsation enhanced heat exchange, the frequency conversion control of the seawater pump is realized by adjusting the speed according to different working conditions. At this time, adding pulsation enhanced heat transfer technology can generate forced convection, increase the turbulence of the fluid in the tube, and introduce convection into the boundary layer, and at the same time produce cavitation, which can improve the heat transfer efficiency of the equipment. After using the seawater pump frequency conversion control and pulsation enhanced heat exchange program, the energy consumption is about 36% of that before the system was installed. The data shows that the program achieves the purpose of environmental protection and energy-saving and has a certain reference value for engineering research.
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Research on modeling and simulation of doubly fed induction wind turbine based on MATLAB/Simulink
Статья научная
This paper first introduces the structure of doubly fed wind power generation system and the working principle of doubly fed induction generator in detail and establishes the corresponding mathematical model of doubly fed wind power generation unit. The control part of wind power generation system based on doubly fed induction generator includes rotor side control and stator side control. The rotor side control adopts the vector control strategy based on stator flux orientation of the double-fed induction generator connected to the grid, and the working principle is analyzed in detail, and the main part of the simulation modeling is given. Stator side control adopts vector control strategy of grid-connected inverter control, and its working principle is analyzed in detail, and the main part of simulation modeling is also given. In order to verify the correctness and feasibility of the system, the simulation experiment platform of doubly fed wind turbine under this control strategy is built by using Matlab/Simulink simulation platform, and its simulation analysis is carried out in detail.
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Research on ventilation and heat dissipation performance of trailer power station
Статья научная
The results show that the use of CFD software to simulate the ventilation and heat dissipation of the trailer power station cabin, Get the flow field and temperature field in the cabin, The position of the highest temperature in the vehicle cabin can be determined quantitatively, which provides a useful reference for the design of the cabin structure of the trailer power station and the arrangement of the equipment in the vehicle. Moreover, the simulation results are in good agreement with the experimental results. It shows that the selected Realizable k-ε Turbulence Model can more accurately simulate the air flow field in the cabin of the trailer power station. It also shows that the model simplification method used in the calculation and the setting of analytical conditions are reasonable.
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Research progress of type P copper (I) oxide in the field of light energy utilization
Статья обзорная
Copper (I) oxide Cu2O, as a representative intrinsic P-type inorganic semiconductor material, has been widely used in the field of optical energy utilization, such as photovoltaic, photocatalysis, photodegradation and other fields, and has an extremely important position. For a long time, the literature on Cu2O’s application technology in the field of light energy utilization is relatively scattered and independent, resulting in a certain degree of obstacles and difficulties to obtain relevant technical knowledge and have a deep understanding of its internal principles. According to the application of Cu2O in the field of light energy utilization in recent years, it is mainly divided into three modules (photovoltaic, photocatalysis, photodegradation, photodegradation), and mainly summarizes the classification, principle and characteristics of Cu2O application in the field of light energy and prospects the optimization method and development direction of the application in the field of Cu2O light energy. This review aims to provide reference and guidance for the optical energy applications of Cu2O and other related inorganic oxide semiconductors.
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Review on nearest level modulation methods based on MMC
Статья научная
In view of the relevant situation of offshore wind power research, development and construction at home and abroad, as well as the energy crisis facing the world, we have ushered in a new opportunity and outbreak period for the development of new energy. Therefore, higher requirements are placed on the power supply, and the key technology for the design of offshore wind power flexible DC transmission high-power converters is proposed. The Modular Multi-level Converter (MMC) topology can only use a lower switching frequency to obtain higher power Waveform quality. The output voltage waveform can effectively reduce the switching loss and filter capacity and improve the efficiency and economy of the converter. Among them, the method based on Level Modulation (NLM) is usually the preferred method. This paper introduces the topology and working principle of the modular multilevel converter (MMC) in detail and describes the improved modulation method for NLM in detail. The advantages, disadvantages and application occasions of different improved modulation techniques are summarized, which provides a reference for the engineering application of MMC.
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Simplification and verification of o-xylene fuel mechanism
Статья научная
The increasing demand for energy due to economic globalization has led to the exploration of different types of fuels, including aromatic hydrocarbon fuels. Xylene is an essential aromatic hydrocarbon fuel and an important component of kerosene. This study employs the error propagation directed relationship diagram (DRGEP) and sensitivity analysis (SA) to simplify the reaction mechanism of o-xylene. The ignition delay time and laminar flame velocity predicted by the fuel mechanism under different w375orking conditions are compared with pre-simplified experimental data. The study proposes a mechanism consisting of 298 reactions and 64 components to describe the combustion reaction of xylene. The simplified mechanism's ability to reproduce experimental results is assessed, and the results reveal that the simplified mechanism effectively reproduces the experimental results, indicating its potential usefulness in practical applications. This study has significant implications for the development of more efficient and sustainable energy sources. By providing insights into the combustion behavior of xylene, researchers can develop more accurate models for predicting the performance of this fuel under a range of conditions. This, in turn, can inform the development of new technologies that can help meet the growing demand for energy in a more sustainable and environmentally friendly way. Overall, this study contributes to our understanding of the combustion behavior of xylene, highlighting its potential as a sustainable energy source and offering a potential avenue for further research in this field.
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Simulation analysis of non-concentric squeeze film damper
Статья научная
Squeeze film dampers are components that provide additional damping for rotating motors. In general, in order to achieve the best results of the squeeze film damper, it is necessary to appropriately increase the damping value, reduce the stiffness and set a reasonable eccentricity. In the process of designing the squeeze film damper, we can apply the rotor dynamics module of COMSOL software to model and simulate it, so as to achieve better simulation results and lay a foundation for the subsequent development and design of the product. In COMSOL software, in order to simplify the modeling of rotor components, we usually model squeeze film dampers based on the damping coefficient. The model calculates the damping coefficient for a short squeeze film damper and compares the results with the analytically calculated values. In addition, the damping coefficient depends on the position of the journal in the damper, i.e., the magnitude of the eccentricity. In this paper, by analyzing the dimensionless damping coefficient, bearing stiffness, journal displacement, and fluid load at different eccentricity, and plotting the fluid pressure distribution and the average oil film flow rate of the squeeze film damper, we can find the most suitable range of eccentricity and the damage-prone part of the damper, which can provide an important reference for the actual design of the squeeze film damper.
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Статья научная
The quality of the control system depends on various factors such as the characteristics of the controlled object, the control scheme, the form and size of interference, etc. In a control system where the characteristics of the object and the hardware and software have been basically determined, the control quality of the system depends on the control algorithm. The control algorithm will make the motion process control have better speed, accuracy and stability. The study of control law is an important part of the control system design of the entire six-degree-of-freedom test bench. The characteristics of the controlled object and the existence of interference in this control system require the designed control law to have the characteristics of strong robustness, certain intelligence, and easy implementation, so as to achieve stable and precise control of the system and achieve the control indicators required by the system. The control strategy of this six-degree-of-freedom test bench adopts Fuzzy PID control, which combines fuzzy theory with the mature traditional PID control theory and uses fuzzy theory to tune the three control parameters of PID to form a parameter self-tuning Fuzzy PID control Device. The Fuzzy PID control strategy is simulated by MATLAB simulation software.
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Simulation of ship trajectory in waves based on STAR-CCM+
Статья научная
The reliable ship motion trajectory signal provides a basis for six-degree-of-freedom test bench to simulate ship motion in waves. The characteristics of ship motion in waves were analyzed. Aiming at the problem of complex hull shape and large displacement at sea, the dynamic overlapping grid technique was used. Based on STAR-CCM+, the free surface was solved by CFD (Computational Fluid Dynamics) numerical simulation method. The numerical model of ship motion in waves was established, and the DFBI (Dynamic Fluid Body Interaction) method was used to simulate the ship motion in the waves. The ship’s motion trajectory was obtained in the regular and irregular heading waves, which provides important support for the six-degree-of-freedom test bench wave simulation system.
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Simulation of waste heat recovery from ship boiler exhaust gas
Статья научная
The heat pipe type waste heat recovery system can effectively reduce energy consumption when the ship is sailing in a polar region, so it has great engineering application value. In order to improve the design of the heat pipe waste heat recovery system and ensure that the design parameters meet the design requirements, this project has carried out a three-dimensional simulation analysis of the internal flow field of the heat pipe waste heat recovery system. Through reasonable model processing, application of boundary conditions, and the assignment of physical attributes the flow field characteristics of the key positions of the heat pipe type waste heat recovery system were obtained scientifically and effectively. The model was simulated and calculated, and the flue gas temperature distribution in the evaporator heat exchange tube, the overall temperature distribution of the waste heat recovery system, and the temperature change curve from the cold water entering the condenser to the steady state were obtained. The change curve of the thermal efficiency of the system during the temperature of the flue gas from the evaporator to the steady state.
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Статья научная
Recently, more and more scholars have devoted themselves to researching new methods of vibration reduction and noise reduction by manipulating the elastic waves in the structure to achieve the purpose of vibration reduction and noise reduction. To this end, a new type of ‘acoustic black hole’ structure is proposed, which reduces structural vibration while avoiding problems such as mass increase. In this paper, the vibration damping performance of the structure is mainly calculated by finite element software, and the energy concentration effect of the thin plate containing the acoustic black hole is verified by finite element analysis. A thin plate structure with four acoustic black holes is proposed. The calculation shows that the structure has obvious vibration reduction effect, and the vibration reduction effect can reach more than 20dB at high frequency.
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Smart counters for implementation in integrated smart grid
Статья научная
This article discusses the concept of Smart Grid and its elements, in particular, smart counters are considered that are an integral part of the intelligent power system, since these counters not only read the consumed electricity but also collect data, transmit and monitor information.
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Some specifications of diesel engine running on gaseous fuel
Статья научная
The paper dwells on the effectiveness the transition of diesel transport-energy equipment to the alternative gaseous fuel, as well as its specific design features. There is justified the possibility of the ignition of a gaseous fuel mixture through the assessment of dosing of the explosive charge, and its influence on the functioning of the process of a gas-air mixture combustion. There are also described the possible positive phenomena, which have sprung during the operation on gaseous fuel.
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South Caucasus transport corridor and potential for its development
Статья научная
The South Caucasus, as an energy-intensive region and transport corridor linking the markets of Asia and Europe, has long played an important strategic role in the trade, economic and political context of East-West relations. Within the framework of economic cooperation between the states of the Caucasus, the creation of a single automated information system for the customs control of transit is necessary for the exchange of information on goods and vehicles in real time. The implementation of these approaches will facilitate the effective utilization of transit potential of the South Caucasus Transport Corridor.
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