Технические науки. Рубрика в журнале - Бюллетень науки и практики
Design of a liquid cooler for a 100 kW semiconductor power converter
Статья научная
He focus of this research in this paper is to design a 100 kW power liquid cooler, semiconductor converter liquid cooler, thus using pulsed thermal medium circulation to increase the capacity of the cooling system on the surface of the power semiconductor device. Based on comparing the parameters of conventional and pulsed coolant circulation mode, the liquid cooling system of power semiconductor converter is studied by physical method. In laboratory testing, experiments are planned according to the order and frequency of changing device operating modes. Finally, the experimental research results are processed, and the relationship between the discharge heat power and the temperature drop and the coolant flow is established by using the mathematical statistics method. Result: Depending on the exhaust heat power and the coolant flow in the range of 3-1.5 L/min, the pulsating heat transfer enhancement in the liquid cooling system of the power semiconductor converter can increase the thermal capacity and the current load of the power semiconductor converter by a factor of almost 2.5 times, respectively. At the same time, the circulation of the coolant in the inner circuit is carried out by a hydraulic powered film pump.
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Design of dangerous driving behavior detection system based on STM32
Статья научная
With the rapid development of China’s economy and the continuous improvement of the living standards of the people, cars have gradually become an indispensable tool for travel. At the same time as the number of cars increases rapidly, the accident rate of road traffic is also increasing. Traffic accidents caused by dangerous driving behavior account for a large part of the accident rate. In order to reduce the road traffic accident rate, a vehicle dangerous driving behavior detection system using STM32 single-chip microcomputer is designed from the vehicle itself, which mainly detects the speed and weight of the vehicle. When the vehicle is in the starting state, the detection system detects the weight and speed of the vehicle in real time through the sensor and the motor speed. In this system, the STM32 is used as a core MCU. When the speed or weight of the vehicle exceeds the threshold, the MCU performs an alarm and subsequent operations. This design introduces the overall design of the system in detail, from the test of each module to the use of the overall connection test, the interface module and STM32 interface circuit as well as the system hardware circuit and related peripheral circuits are given, and finally the measurement data is displayed through the OLED. The design is simple in structure and can be applied to various vehicles.
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Design of fishing vessel lighting system based on force-controlled wind-solar complementarity
Статья научная
This paper focuses on the lighting system of fishing vessels, and the emergence of histograms has brought a new vitality to the development of the lighting of fishing vessels. In this paper, after summarizing the knowledge of wind and solar complementary technology, combined with the design needs to use the configuration control of each part of the control function to put forward a series of control schemes. Explains the background of the project development and its importance and introduces the key technical situation of the wind and light photoelectric complementary and the use of solar wind energy in the ship. Master the wind and solar complementary technology overview and summarized the independent wind power generation system and independent photovoltaic power generation system technology as well as the characteristics and working principle of wind and solar complementary power generation. Obtain the specific parameters of each component, including marine lighting parameters, wind turbine parameters, photovoltaic solar panel power generation parameters, in order to prepare for the simulation afterwards. Software base before simulation, simulation according to the requirements of the design, including the design of wind turbine, photovoltaic solar panels, the design of the fishing boat lighting load, and finally the results of the simulation are analyzed as well as the conclusion.
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Design of heat pipe air preheater for 10 t/h gas-steam boiler
Статья научная
This design is aimed at energy -saving and designed a heat pipe air preheat to recover 10 t/h steam gas boiler flue heat waste heat, thereby increasing the efficiency of the boiler and reducing gas consumption. This article first introduces the thermal pipe, heat pipe heat exchange, and boiler thermal system, and then focus on the design and optimization of the heat pipe air heater. This design optimizes the thermal pipe specifications of the heat pipe air heater and the parameters of the fins. At the same time, the sealing structure, the fixed structure, and the airport structure are optimized. Subsequently, the UG software created a three-dimensional physical model model and rendering model, and finally proposed corresponding countermeasures on equipment corrosion, thermal pipe life and tube vibration problems. This design uses Excel software to make design calculation tables. Through input parameters, the results of the results of the number of thermal pipes can be obtained.
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Design of metal sulfide electrode for hydrogen production by electrolysis
Статья научная
Hydrogen evolution reaction (HER) is the cathodic hydrogen evolution reaction in electrolytic cell, but the hydrogen evolution catalytic properties of electrode materials best remains is the precious metal catalyst, therefore, in order to study the catalytic performance is good, and cheap hydrogen evolution electrode materials has become the research hot spot, metal sulfide can be mixed and with good electrical conductivity is it can be used as a necessary condition for hydrogen evolution electrode, The core theory of this paper is the first principle. By taking metal sulfide as the matrix and doping it with 10 metal group elements, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn, we obtained the configuration of 20 metal sulfide by doping it at two different sites of S atom, and inlaid H atom into metal atom. Then, through the use of software to study its catalytic performance, through the free energy analysis, rate analysis, bond length analysis, density of states analysis, charge analysis method, compared and found the most suitable doping metal element V, thus also determined that metal sulfide can be used as hydrogen evolution electrode through metal doping.
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Статья научная
As a new type of heat exchanger with compact structure and efficient performance, microchannel heat exchangers have good application prospects in industries with strict requirements such as energy and power, petrochemical, aerospace, and other industries. Therefore, exploring the performance and heat transfer characteristics of microchannel heat exchangers is of great significance. This article designs a performance testing system that can simultaneously explore the enhanced heat transfer inside the pipeline of water water and carbon dioxide compressed air microchannel heat exchangers. The variable working fluid circuit design is used to analyze the factors that affect the enhanced heat transfer. The Control variates is used to control the heat transfer conditions, explore the difference of heat transfer performance between different working fluids under different flow rates, inlet temperatures and other conditions, and analyze the heat transfer performance of different channel types by comparison method. The results indicate that when the hot water flow rate range is 2.063×10-5~2.556×10-5m3/s, Re-5~2.556 ×10-5m3/s, the Reynolds number and Nusselt number in the pipeline increase with the increase of inlet flow. In the carbon dioxide compressed air heat transfer experiment, when the flow rate range is 2.810×10-4~3.182×10-4m3/s, the Nusselt number and convective heat transfer coefficient of the 3.6mm inner diameter microchannel are always greater than the Nusselt number and convective heat transfer coefficient of 6.6mm. When the pipe diameter is the same, the water water microchannel heat exchanger has better heat transfer performance and smaller pressure drop compared to the carbon dioxide compressed air microchannel heat exchanger.
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Designing a cooler with natural cold for a 100 kW semiconductor power converter
Статья научная
The subject of the study is the design of a cooler with natural cooling capacity for a 100 kW semiconductor power converter. The purpose of this thesis is to design a cooler with natural cooling capability for a 100 kW semiconductor power converter and to evaluate its practical effects. We summarize the demand for power semiconductor devices for new applications in power electronics in recent years. During the study and testing of the cooler for the 100 kW semiconductor power converter, the parameters that became the basis for mathematical modeling were determined. In this paper, we summarize the key issues and the current state of research on power semiconductor modules, including module thermal design and thermal modeling issues. The degree of realization is complete. In the process of developing the experimental device, reduction of energy consumption losses and reduction of explosion and fire hazards in industrial production facilities was achieved, which in turn will increase the efficiency of the invention and reduce its production costs. Development of efficiency - reduction of power consumption losses, reduction of explosion and fire hazards in industrial production facilities due to overheating of power semiconductors.
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Designing of a cavitation heat generator for heating water with a capacity of 10 kW
Статья научная
This article establishes a three-dimensional model of the design circuit of a water heating cavitation device and simulates it in Hysys software. The relationship between temperature, pressure and flow rate of cavitation generator in pulsed heating water circulation unit is studied by using control variables. The dependence of pressure and temperature difference on flow rate was studied. The dependence of pressure and temperature difference on the thermal power of the cavitation device was studied. The dependence of pressure and temperature differences on pipeline diameter was investigated. Explored the differences in pressure and temperature through water flow methods in pulse and stationary modes. The following conclusions can be drawn: 1) When the flow rate and output thermal power remain constant, the pipe diameter is inversely proportional to the pressure; 2) When the pipe diameter and output thermal power remain constant, the flow rate is proportional to the pressure; 3) When the total output power is 10 kW, the outlet temperature of the system gradually rises to a relatively stable state after 1000 seconds for different power cavitator schemes; 4) When the total output power is basically equal, the more times the parallel connection is made, the smaller the voltage drop, and the higher the system efficiency; 5) When the pipe diameter and output heat power are constant, the larger the flow rate, the smaller the temperature after the cavitator and the temperature difference between the front and back become smaller. When the pipe diameter and flow rate are constant, the smaller the output thermal power, the smaller the temperature after the cavitator and the temperature difference between the front and back become smaller.
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Designing of a liquid cooler with a phase transition with a power of 5 kW
Статья научная
A diagram and installation of a prototype of a two-flow heat pipe with the ability to regulate the parameters of the working environment have been developed. The installation allows the heat pipe to operate in both normal and pulsed cooling modes. Data were obtained that made it possible to obtain the dependence of the heat transfer coefficient on the heater power, and the heat transfer coefficients in stationary and pulsed modes were determined. In this article, the Aspen Hysys software package is selected as the software and circuit simulation. As a result of theoretical studies, it was established that the heat transfer coefficient of a heat pipe in pulsed mode is 12% higher than in stationary mode with the same initial coolant parameters. Based on the results of the work, it is proposed to use the method of pulsed supply of liquid coolant as one of the ways to increase the heat transfer of a heat pipe.
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Development of a hydraulic damping device to protect a centrifugal pump
Статья научная
This study focuses on the utilization of hydraulic accumulators to mitigate hydraulic shock. The pressure energy within the system is converted into compressed gas energy in the accumulator. This continuous conversion between the two forms of energy allows for the absorption of hydraulic shock force, thereby ensuring system stability. The study involved the creation of experimental circuits, which were tested both with and without the inclusion of a hydraulic accumulator. The results confirmed that the accumulator has a substantial impact on reducing hydraulic shock phenomena. The study's findings demonstrate that the shocks in the hydraulic system can be efficiently managed by selecting an appropriate inflation pressure for the accumulator and utilizing various connection line data.
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Development of a prototype hydraulic damping device for hot water heating circuit in pulse mode
Статья научная
This paper provides a comprehensive exploration into the design and implementation of the hydraulic damping device within a pulse mode hot water heating loop. It outlines a systematic approach aimed at optimizing system performance, detailing the operational principles of the pulse mode heating circuit and presenting a structured construction scheme for the hydraulic damping apparatus. Accompanying this analysis is a simplified diagram illustrating the hydraulic damping system, offering a clear visual representation of its integration within the heating circuit. Through mathematical transformations, essential parameters such as complex impedance, frequency function, and vibration frequency characteristics are derived, providing valuable insights into the dynamic behavior of the system. Culminating this investigation, the paper constructs the frequency response of the circuit, offering a comprehensive understanding of its dynamic behavior across varying frequencies. This synthesis of theoretical frameworks and practical applications advances our understanding of pulse mode hot water heating technology, paving the way for enhanced efficiency and performance in heating systems.
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Development of a prototype non-volatile heating circuit with pulsating mode
Статья научная
The emergence of global energy crisis makes energy saving technology become the key technology of sustainable development. Enhanced heat transfer technology can improve the efficiency of various heat transfer equipment and reduce the weight and volume, which plays a vital role in energy saving and sustainable economic development. In recent years, based on theoretical and experimental research, Chinese researchers and technicians have developed many new technologies to strengthen heat transfer, such as cross-scaled elliptic tube, discontinuous double-inclined inner rib tube, spiral groove tube, spiral groove tube, inner fin tube, twisted elliptic tube and so on. Among them, the pulsating heat transfer technology is an efficient and energy-saving means that can significantly strengthen the convective transport operation and improve the heat transfer effect. Through fluid pulsation or the vibration of the heat transfer pipe, the technology can remove the dirt deposited on the heat exchange surface, reduce the thermal resistance of the dirt, and improve the performance and life of the heat exchanger. It is widely used in the cooling of electronic components, automobile turbines, and the utilization of atomic energy in Marine environment. Firstly, the construction scheme of the experimental device is proposed, and the working principle of the experimental device is described in detail. The complex impedance, frequency function, amplitude-frequency characteristic and phase-frequency characteristic are obtained by mathematical transformation of power supply circuit. Finally, the frequency response of the circuit is constructed.
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Статья научная
The hot water supply system is one of the important components of the water supply and drainage system of high-rise civil buildings. With the development of the national economy and the improvement of people’s living standards, people’s requirements for popularizing hot water supply and improving hot water supply technology are becoming more and more urgent. In the process of hot water supply, the flow pressure of the pipeline is increased, and the purpose of hot water supply in high-rise buildings is achieved. The experiment analyzes the effect of the pressure ratio on the pipeline in front of the accumulator and the impact valve on the flow of coolant through the check valve. First, through the periodic opening and closing of the shock valve, the pressure continues to rise and fall, and the spring hose exhibits periodic pulsation. The effects of different pressure ratios on pipeline pressure and flow rate are studied, and the data of simulation calculation and actual measurement are analyzed through experiments. The research results have practical significance for improving the water supply efficiency of the hot water supply system of high-rise buildings.
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Development of wide bandgap one-dimensional MOF/TiO2 photonic crystal and its gas-sensing properties
Статья научная
Metal-organic framework (MOFs) materials are a type of coordination polymer that have seen significant breakthroughs in material science over the past decade. Because of their high specific surface area and porosity, they are widely used for gas adsorption, storage, and separation. Additionally, their structural tunability allows for a wide variety of MOFs, with more remarkable properties yet to be discovered as research continues. When MOFs are applied in photonic crystals, adjustments to their structure enable them to act as specific gas-sensitive materials, causing shifts in the photonic crystal's forbidden band after gas adsorption. This generates distinguishable signals for effective sensing. In conventional single-metal MOFs, doping with another metal to prepare photonic crystals increases defect size while reducing symmetry and simplicity, leading to more pronounced forbidden bands and improved sensing. Therefore, in this thesis, we aim to partially replace the chromium in MIL-101 with magnesium and then self-assemble it with titanium dioxide to prepare photonic crystals. This approach aims to leverage the exceptional properties of MOFs, resulting in photonic crystals with improved gas-specific recognition and sensitivity, further enhancing their gas-sensing capabilities.
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Статья научная
This paper investigates the dynamic pricing and energy management of integrated electric and thermal energy systems through the Stackelberg game approach, for the upper tier leader problem, the revenue of the integrated energy system as a whole is used as the objective function, taking into account the electricity price and related constraints such as the heat price, for the lower follower problem, a leader-follower Stackelberg game model is constructed with the highest user satisfaction as the objective function, Constraints such as power balance conditions and thermal balance conditions of the system are also taken into account, The upper level of the model is solved using a differential evolutionary algorithm, Lower level solver using CPLEX solver. The simulation results show that the proposed model not only effectively weighs the interests of the integrated energy system and the customer aggregator, but also achieves a win-win situation for both the customer aggregator and the external grid, and the solution algorithm used protects the data privacy between the integrated energy system and the customer aggregator.
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Economic analysis of gas supply system for dual fuel engines with life cycle cost
Статья научная
The regulations of the international maritime organization (IMO) on ship emission are becoming increasingly strict. Liquefied natural gas (LNG) is an ideal alternative fuel for vessels, considering its environmental and economic advantages. This paper compares the life cycle cost (LCC) of LNG ships low pressure gas supply system (FGSS). Comparative analysis of the three main pressurization modes for supplying LNG in the low-pressure gas supply system, namely external gas source pressurization, self-pressurization and cryogenic pump boost. Through modeling in Aspen HYSYS software, system operation is simulated, life cycle costs are compared, and the implementation effects of the three system schemes are analyzed and evaluated. The application of life cycle economic analysis in ships mainly focuses on the overall energy saving and emission reduction of ships. Its application in low pressure gas supply systems for dual-fuel engines is rare. This study helps the gas supply system choose the most economical and applicable scheme in practical applications.
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Статья научная
In this paper, the heat transfer performance of porous microchannels sintered with spherical and dendritic copper particle is compared. The working fluid is deionized water. For uniform particle size sample, the dendritic-particle microchannel presents better boiling heat transfer performance than the spherical-particle one. It includes higher critical heat flux (CHF), which was related to the connected pore structure of the dendritic copper powder. For mixed particle size sample, the dendritic-particle microchannel also shows higher heat transfer coefficient and CHF. At high heat flux, the dendritic-particle microchannel can effectively suppress the pressure pulsation and maintain a relatively stable flow boiling state in the microchannel.
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Статья научная
The development of active and selective catalysts for the synthesis of vinyl acetate from ethylene and acetic acid, the effect of the amount and ratio of individual components of the catalyst to control the catalytic properties of the introduced components were studied. In vinyl acetate synthesis, the effects of each component were studied to describe the effect of catalyst constituents on its properties, and empirical one-factor mathematical dependencies were obtained. Their generalized mathematical relationships of the activities of the catalysts, defined as the rates of the reactions of the formation of vinyl acetate and CO2, have been proposed. As a result of the research, a mathematical model was proposed to select the most optimal composition of the catalyst. The activity of the catalyst containing 0.4%Pd+4%Cu+7%CH3COOK/HSZ averaged 700 g VA/(l×cat×h) at 93-97% selectivity of ethylene - vinyl acetate formation.
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Effective methods improving the load-bearing ability of clay bricks and walls
Статья научная
An analysis of major earthquakes over the last 60 years reveals the preponderance of structural damage, building collapse, and fatalities to have occurred in individual buildings of the residential sector. This highlights a serious problem in the rural districts of Central Asia, where more than 65 percent of residential construction uses clay-based materials. For these reasons we are currently developing new ways, based on the old time-honored techniques, to improve the strength and durability of clay as a building material so that locally constructed houses are better able to withstand seismic effects. In this paper presents the third methods of improving traditional building technologies and clay’s ability to withstand seismic forces. These methods are short fibers, thermoprocessing and of compacted soil cement block and brick which based to inexpensive materials.
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Efficient aspect ratio of the wing with at winglets
Статья научная
In the article, by the method of the system of equations of steady horizontal flight the effective aspect ratio of the wing with AT winglet wingtips is explored. The total aerodynamic force, created by all four parts of the wingtips is determined. The vector of the total aerodynamic force of the wingtips is represented in the form of components of a linked coordinate system. Equilibrium equations for the steady rectilinear motion of an aircraft with AT winglets type wing tips in a horizontal flight are recorded. From these equations it is obtained that, in the direction of motion, the longitudinal component of the vector of the total aerodynamic force of the tips reduces the force of the drag of the wing, the vertical component is added to the lifting force of the wing and increases it, and the lateral component, due to the symmetry of the wing, is zero. The coefficient of inductive drag of the wing with the tips is written in the form of the difference in the inductive drag of the wing without the tip and the coefficient of the longitudinal component of the total aerodynamic force of the tips. Writing the coefficient of inductive drag of the wing with the tips in the traditional form through the coefficient of lift and aspect ratio of the wing, the expression for the effective wing aspect ratio with the AT winglets, which is longer without aerodynamic termination. An important consequence is that at the constant weight of the aircraft, the product of the effective wing aspect ratio with aerodynamic wingtips to its coefficient of inductive resistance is a constant value, independent of the kind of the wingtips. It is shown that with increasing flight speed, and also by reducing the inductive speed, the aspect ratio of the wing decreases.
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