Технические науки. Рубрика в журнале - Бюллетень науки и практики
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 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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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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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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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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Electric vehicle charging scheduling and pricing based on Stackelberg game
Статья научная
The disorderly charging and discharging of a large number of electric vehicles will have a serious negative impact on the safety and economic operation of the power system. In order to avoid safety problems and obtain maximum economic benefits, a master-slave game is proposed to model the maximization of profits for agents and car owners. In the upper model of the model, the optimization objective of the main body is to minimize the operating cost and minimize the load mean square error; in the lower model, the goal is to minimize the cost of electric vehicles; the particle swarm algorithm is used, and the model decoupling characteristics are used from the inside to the outside. Solve the Nash equilibrium point of the optimization model, obtain the set of optimal time-of-use electricity price and electric vehicle charging and discharging scheme, and finally obtain the global optimal pricing strategy. Various typical scenarios before and after optimization are compared and analyzed in detail through calculation examples, and the effect of the proposed model and the overall scheduling benefit are verified.
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Presents the results of studies (research) on the use of silica raw materials from the production waste of refinement tailings of antimony ores (or antimony ores refinement tailings) and basalt fiber waste, their influence on the quality characteristics of non-autoclave aerated concrete.
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Enhanced heat transfer of heat-exchange equipment by pulsating air flow
Статья научная
This paper designs a pulsating generator to provide pulsating air flow for experiments the relationship between the average flow velocity, pulse and pulsation amplitude and the pulsating flow enhancement heat transfer ratio was discussed respectively. The characteristics of the pulsating flow enhanced heat transfer were analyzed, and the academic research and engineering application of pulsating heat transfer was proposed. This inevitably has an optimal pulsating frequency value at which the maximum vortex generation can be obtained within one pulsation cycle to obtain maximum heat transfer effect, for example, in this experiment; the optimal frequency is 1-1.25 Hz. The effect of Reynolds number Re on the low-frequency pulsation convection heat transfer process is that the low-frequency pulsation can only enhance the convective heat transfer within a certain range of Reynolds numbers. If it exceeds this range, the convective heat transfer is weakened.
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Статья научная
Study of urban public transport management on the basis of logistical approach today is of high relevance. For a long time, logistical concepts in transport have only been applied in the freight transport field of activities. However, logistical principles might be meaningful for systemic organization and management of civil passenger traffic. The given paper describes the use of logistical approach and technique in passenger transport, as a logistical chain of operators and infrastructure interacting through logistical links allowing for optimizing the production of transport services, meeting the needs of different population categories through the proper management of available economic resources. The paper proposes the use of logistical approaches in the systems of urban public transport. They should help to formulate the new principles of management, planning and control over material and their attendant flows, and to become the main competitive advantage in the market of transport services.
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Статья научная
In this research, the thermal-hydraulic performance of plate heat exchanger (Ridan HHN no. 04) used in domestic water system is investigated experimentally. The hot lubrication/water inlet keep temperature and flow rate constant at 72 °C and 0.8-0.1 L/s, the cold-water inlet remained 12 °C with different velocity. Then the convective heat transfer coefficient increases with enhancement of Reynolds number. Moreover, it is observed that Fanning friction factor decreases with an increase of the Reynolds number and it is showed by the figure. Therefore, it is possible to find that the increase of the Peclet number results in an increase of the Nusselt number as well when Peclet number in water - water smalls than 2500. Finally, we get heat exchanging performances of cold side in lubrication/water - water using plate heat exchanger.
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Experimental research on heat dissipation at the hot end of semiconductor refrigeration chips
Статья научная
TEC1-12705 and TEC1-12706 two types of semiconductor refrigeration chips were designed with different hot-end heat dissipation conditions. At the same time, a test device for heat dissipation of heat pipes for heat sinks with separate current input and two-stage refrigeration was designed, and the influence of hot-end heat dissipation conditions on cold-end temperature was analyzed. The test results show that the cold terminal temperature of the semiconductor refrigeration sheet is related to the heat dissipation capacity of the hot terminal. Under the condition of limited heat dissipation capacity, the cold terminal temperature decreases first and then increases with the increase of the input current; and under the condition of ensuring the heat dissipation capacity, the cold terminal temperature decreases with the increase of the input current and decreases with the decrease of the hot terminal temperature. The two-piece TEC1-12706 semiconductor refrigeration sheet adopts two-stage refrigeration with separate current input, and the minimum temperature of the cold terminal can reach -36,8°С. The test results show that improving the heat dissipation conditions of the hot end can improve the performance of a single semiconductor refrigeration sheet. At the same time, under the best heat dissipation conditions, the use of separate current input two-stage refrigeration can greatly reduce the temperature of the cold end, which is of great significance to improve the working temperature difference of the semiconductor refrigeration sheet.
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Experimental study of cavitation heat generator for heating water
Статья научная
The energy released by cavitation is a new method to make full use of energy. Based on this, a new type of cavitation heat generator for heating water is designed. A conical core is used instead of the traditional throttling element to build a set. Closed circulation system device, the performance of the cavitation heat generator when the cone core with different cone angles was tested in the test. The temperature difference and pressure difference before and after the three groups of liquid medium flow through the cavitation heat generator were measured experimentally. The results show that the cavitation heat generator with a 30-degree tapered core has the best performance and improves the heating efficiency of the feed water, which has a great reference value for the further study of cavitation heat transfer.
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