Технические науки. Рубрика в журнале - Бюллетень науки и практики
Design and analysis of heat pipe heat exchanger efficiency
Статья научная
The heat pipe has a high thermal conductivity, and its basic working principle is to transfer heat through evaporation and condensation through the working medium inside the pipe. Heat pipe has good thermal conductivity, isotherm and other characteristics, and the heat transfer area at both ends can be changed at will, control the temperature and other advantages. Therefore, the heat pipe heat exchanger has the advantages of high heat transfer efficiency, compact structure, small fluid resistance loss, and beneficial to control dew point corrosion. At present, it has been widely used in metallurgy, chemical industry, oil refining, boiler, ceramics, transportation, light textile, machinery and other industries, as energy saving equipment for waste heat recovery and heat energy utilization in the process and has achieved remarkable economic benefits. The design of the heat pipe heat exchanger on the development of the current situation, development trend, application, design principle and design process of a simple description, while focusing on the discussion of the heat pipe heat exchanger design process. The main content of the heat exchanger thermodynamic calculation, structural design and material selection. The model of heat pipe heat exchanger is established according to the actual situation and the calculated data.
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Design of PFC converter based on interleave boost
Статья научная
Based on the principle of stagger boost PFC, this paper expounds the application value of stagger PFC theory by developing a scientific and feasible scheme and using Matlab simulation. According to the subject requirements, the use of UCC28070 to achieve PFC control function. And learn IC functions. Based on the theory of interlaced PFC, the most suitable electronic device is selected to adjust each part of the circuit. Finally, Solidworks and Protel software were used to draw the radiator and PCB boards, then the prototype was made and debugged, and the final result was obtained.
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Статья научная
The subject of the research is designing a regenerative heat exchanger to heat hot water. Qualitative and quantitative analysis of relevant physical parameters to optimize heat exchanger models. The purpose of this study is to simulate realizing the goal of heating hot water with 25 kW and optimize the model to optimize the heat exchange efficiency in practical work. As a result of the research, Amplitude-frequency response of the circuit increases linearly as speed of rotation. When the speed is constant, the less of water mass is, the value of Amplitude great. The phase frequency response of the circuit increases overall as the speed increases. The greater the mass, the greater, and the rate of increase gradually decreases. we know that increasing the water volume can improve the heat transfer efficiency, but when the water volume (G) increases to 1.6, the rate of increasing the heat transfer efficiency begins to decline, so this should be taken into account in the design process. With the heating time increases, the heat transfer efficiency will also improve. It should be noted that when the heating time increases, the rate of increase of heat transfer efficiency decreases and specific heat capacity (KF) decreases.
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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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Development of an Experimental Heat Pump Installation with a Pulse Capacitor
Статья научная
Based on the prototype experiment of a dual-loop heat pipe with enhanced cooling technology, this study develops a numerical simulation model in SolidWorks and Aspen to analyze the thermal performance of a novel heat pump system integrated with a pulse capacitor. The simulation replicates the experimental conditions, including two operational modes (steady-state and pulsed flow), while investigating the effects of key parameters such as heating power and coolant flow rate on heat transfer efficiency.The SolidWorks flow simulation module is employed to visualize the temperature distribution, flow characteristics, and pressure drops within the system. Results demonstrate that the pulsed flow mode enhances the heat transfer coefficient by 18-22% compared to steady-state operation, while the pulse capacitor effectively regulates flow pulsation frequency at 1 Hz. The simulated data shows good agreement with experimental measurements, with deviations within ±6%.This work provides a validated digital twin model for optimizing pulse-capacitor heat pump systems, offering insights into thermal performance enhancement through flow pulsation control. The findings contribute to the development of compact, high-efficiency thermal systems for district heating and domestic hot water applications.
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Development of an Experimental Thermosiphon Installation for Ethanol Production
Статья научная
This study conducted simulation and experimental analyses on an ethanol thermosiphon device integrated with a novel pulsed capacitor heat pump system, investigating its heat transfer and phase-change characteristics. The device heats ethanol liquid in a container, causing it to vaporize. The resulting vapor is then cooled and re-liquefied in a condenser by flowing cold water, enabling continuous heat transfer. The study employed SolidWorks Flow Simulation to visualize temperature distribution, flow characteristics, and pressure drop variations within the system. Aspen numerical simulations were used to calculate thermosiphon efficiency and heat transfer coefficients. Experimental results demonstrated that the system achieves stable ethanol phase-change cycling, with the condenser effectively removing vapor heat. Simulation and experimental data showed good agreement, validating the model's reliability. Compared to steady-state operation, pulsed flow mode increased the heat transfer coefficient by 18-22%, while the pulsed capacitor effectively regulated flow pulsation frequency within the 5-15 Hz range. This research provides valuable insights for optimizing thermosiphon device design and two-phase heat transfer control.
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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 article examines the impact of digitalization on adjustment and maintenance processes in the oil and gas sector aimed at optimizing energy consumption. Modern technologies such as big data analysis, the Internet of Things (IoT), and Machine Learning (ML) algorithms are discussed, highlighting how they assist companies in reducing energy consumption and enhancing operational efficiency. Examples of the implementation of these solutions in major companies are provided, demonstrating significant reductions in energy costs and equipment downtime. The advantages of contemporary approaches over traditional adjustment and maintenance methods are emphasized.
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