Air Door Research Articles

An air door opening and closing time identification and stage division method based on the wind speed data of a single sensor

In mines, tunnel ventilation is monitored using wind speed sensors to measure the stability of the mine ventilation system. However, opening and closing the air door will cause violent fluctuations in the monitoring data of the wind speed sensors. When false alarms are triggered, the staff can diagnose only the mine ventilation system based on their experience. A numerical simulation method is adopted to explore the changes in the flow field during the opening and closing of the air door to address this issue. In addition, a method that is based on the wind speed data of a single sensor is proposed to identify the time and divide the stages of air door opening and closing. The experimental results showed that the proposed method can successfully identify the air door opening and closing time and apply stage division when needed.

Research on Location Selection of Personnel Door and Anemometer Based on FLUENT

The structural design of ventilation structures and the arrangement of anemometers in the main ventilation roadway of an underground mine play an important role in the accurate measurement of air speed. It is one of the important tasks of mine ventilation management and intelligent-ventilation-system construction to determine the position of anemometers. In this paper, the CFD numerical simulation method is used to determine the position of the personnel door in the automatic air door by FLUENT software simulating and analyzing the air-speed cloud diagram and air-pressure cloud diagram in the two-dimensional roadway model. Under the same air speed, comparing the air-speed distribution of different cross-sections in the three-dimensional roadway model when the wide door and the personnel door are opened, the anemometer is set at the 25 m cross-section behind the air door, and the air-speed distribution of the cross-section at different air speeds is simulated. The average air-speed line and the specific installation position of the anemometer on the line are obtained by Origin software. The result shows that the position of the personnel door is 400 mm from the middle line of the roadway, and the measurement error of the anemometer is small on the left side of the roadway (0.41, 2.45) and the right side of the roadway (4.59, 2.43) at 25 m behind the air door, which provides a theoretical basis for the measurement of air speed in a coal mine ventilation roadway.

Temperature Distribution and Equipment Layout in a Deep Chamber: A Case Study of a Coal Mine Substation

With the gradual depletion of shallow resources, the process of resource exploitation is being transferred to greater depths. The temperature of the surrounding rock increases gradually in the process of deep mining, and the temperature of the underground substation chambers often exceeds the normal working temperature in summer. In this paper, the equipment layout and ventilation conditions of the deep substation chamber of the Jiangxi Qujiang Mining Company were selected as the research subjects, and numerical simulation software was used to study the temperature distribution within the chamber under different conditions by changing the combinations of the wind velocity and air temperature of the inlet air of the chamber. The study showed that, under the conditions of the current equipment layout and air door size, the equipment temperature was prone to being too high in the summer. Therefore, the layout of the equipment was optimized based on the simulation results. The transformer equipment was changed from the original serial mode to the juxtaposed mode, and the size of the air door was increased, which effectively reduced the disturbance of the air flow and the length of the air flow path in the chamber. This meant that the high temperature area of the chamber was at the end of the chamber, which efficiently reduced the area of the high temperature zone and ensured that the equipment was in a lower temperature environment. This method can be used as a reference for temperature distribution, layout, and temperature control measures within buildings.

Improve Security in Smart Cities Based on IoT, Solve Cyber Electronic Attacks with Technology by using Packet Tracer

Smart cities are expected to significantly improve people's quality of life, promote sustainable development, and enhance the efficiency of operations. With the implementation of many smart devices, c problems have become a serious challenge that needs strong treatments, especially the cyber-attack, which most countries suffer from it. My study focuses on the security of smart city systems, which include equipment like air conditioning, alarm systems, lighting, and doors. Some of the difficulties that arise daily may be found in the garage. This research aims to come up with a simulation of smart devices that can be and reduce cyber attach. Use of Cisco Packet tracer Features Simulated smart home and c devices are monitored. Simulation results show that smart objects can be connected to the home portal and objects can be successfullymonitored which leads to the idea of real-life implementation and see. In my research make manysolutions for attachingissues,which was great, and apply some wirelessprotocol.

Characteristics of Airflow Reversal of Excavation Roadway after a Coal and Gas Outburst Accident

Determining the influence scope of the airflow disorder is an important problem after coal and gas outburst accidents in ventilation systems. This paper puts forward the indexes of airflow disorder, including the length of the excavation roadway, the outburst pressure, the pressure difference of the air door, and the air quantity of the auxiliary fan. Using the orthogonal table of L9 (34) and numerical simulation method, the characteristics of airflow reversal are studied, and the outburst airflow reversal degree is calculated should the ventilation facility fail. Furthermore, on the basis of fuzzy comprehensive optimization theory, the comprehensive evaluation model of the airflow disorder is established. The results show that the length of the excavation roadway is the most important factor affecting the stability of the ventilation system, followed by the outburst pressure, pressure difference of the air door, and air quantity of the auxiliary fan. The influence of a gas outburst accident on the return air system is greater than that on the inlet air system, and a larger air velocity has a greater impact on the ventilation system, especially the air inlet part. Moreover, the airflow reversal degree of the ventilation system increases with the increase of the outburst pressure or decreases with the length of the excavation roadway. This paper provides a basis for the prevention of gas outburst accidents.

The Airflow Reversal Law in Ventilation System after Coal and Gas Outburst in Tunneling Roadway

Considering the coal and gas outburst phenomenon in the mining space, this paper analyzes the main characteristics of coal and gas outburst accidents, defines the outburst airflow reversal degree, and constructs a simplified topology graph of tunneling ventilation system, while the air door is not destroyed. Using the numerical simulation method, this paper elaborates on the relationship between the outburst pressure and airflow reversal degree. The results indicate that the inlet pressure increases to 264 hPa and the outlet pressure increases to 289 hPa when the outburst pressure increases from 1 hPa to 1 MPa, and the relative variation coefficient of pressure decreases from 1501.5 to 1.62 in the inlet of return airway and decreases from 2002 to 1.65 in the outlet of return airway. Furthermore, the air velocity decreases from −1.38 to −284.44 m/s in the inlet and increases from 3.10 to 297.38 m/s in the outlet. Moreover, the gas concentration of the inlet and outlet in return airway increases rapidly with the increase of outburst pressure. When the outburst pressure is greater than 0.15 MPa, the gas concentration will be over 98% in tunneling ventilation system. This paper also finds out a cubic polynomial relationship existing between the reversal degree and the outburst pressure. It provides the prediction of coal and gas outburst and serves as a guidance in case mine ventilation disturbances occur.

Research on the Force Characteristics and Structural Optimization of Mine Antioutburst Door under the Influence of Coal and Gas Outburst Impact Airflow

In order to deeply explore the destructive effect of the impulsive airflow on the mine antioutburst door when coal and gas outbursts occur in underground coal mines, a large-scale coal and gas outburst dynamic effect simulation experiment device is used to carry out the coal and gas outburst disaster simulation experiment. The impact load and deformation characteristics of the antioutburst door under the impact airflow during coal and gas outburst are analyzed, and the experimental results are discussed in depth through numerical simulation analysis and field example analysis. Based on this, the internal and external causes of the damage of the antioutburst door on the coal mine site are analyzed, the key technologies that need to be solved in the design of the antioutburst door’s disaster resistance are studied, and the overall design of the structure optimization design of the antioutburst door is proposed. The research results show that after coal and gas outburst, the pressure on the antioutburst door will rise and fall, and the fluctuation will be greater. Under the same installation position, the farther the antioutburst door is from the protruding point, the less pressure it bears. In the middle and late stages of the outburst, intermittent negative pressure of the gas at the antioutburst door appeared. The key technologies for the design of the antioutburst door and its disaster resistance mainly include that strengthen theoretical and experimental research on the formation mechanism of outburst shock waves in mines, the interaction mechanism between disaster shock loads and dampers, and the magnitude of disaster expected shock loads; optimize the structure of the antioutburst door size, the width of the contact surface between the air door and the door wall, the stress distribution of the air door under impact load, the design of the safety hole, and the locking device; and improve the disaster monitoring and alarm capabilities of the antioutburst door and collect changes in antioutburst door pressure in real time. The research results provide a theoretical basis and technical support for the optimization of the antishock performance of underground antioutburst doors in coal mines and have important practical significance for improving the disaster resistance of the ventilation system.

Rancang Bangun Buka Tutup Pintu Air Otomatis Pada Irigasi Sawah Berbasis Arduino Dan Monitoring Menggunakan Android

Irrigation sluice gate is used to stabilize the water stream in agricultural channel. In the traditional agricultural type, the sluice control method is applied with fully human assistance. In this study, the system made to open and close the irrigation gate is controlled automatically based on Arduino Uno and monitor using an android system to ease the human work. This system is made using atmega 328 microcontroller as a central control, flow meter sensor as air flow calculation, water level sensor as air level calculation, Bluetooth HC-05 module which is used as a liaison between tools and android, Android is used as an interface between users and devices, android is also used as the monitoring tool, and dc motors are applied to raise and lower the air door. This system works by connecting the device and Android via Blutooth HC-05 then activated the button of door 1 in the android system, then the motor will work to open door 1 with a speed of 99rpm in 2.24 seconds, the water that comes out will be read by a flow sensor and generate the value of 2. If the setpoint on the flow meter has been reached level 0, the motor will close the gate 1 automatically. Furthermore, when it rains and the water level rise then touch down the water level sensor, it will produce the value of 1 then the motor at door 2 which is a disposal door will open at 99rpm in 2.24 seconds.

Experimental study on the characteristics of overpressure wave to ventilation facilities during gas explosion and automatic shock relief devices

Ventilation facilities could easily be destroyed by gas explosion in a coal mine and usually lead to the cascade collapse of the entire ventilation system. Altering the ventilation facilities could increase the value of the overpressure peak and the propagation speed of the shock waves. The attenuation law for blast waves in restricted roadway networks was analysed, and calculation models for the blast wave overpressure and attenuation of the smoke flow velocity in tunnelling roadways were derived. An overpressure relief air door with a magnetic lock was then designed. This air door is opened by the action of the blast overpressure to relieve the pressure in a large section. The air door is automatically reset after the shock wave passes and closes under its load force and body weight. The system has the function of continuous automatic pressure relief and reset, providing support for efficient emergency rescue operations.

Study of the conservation and exhibition of burned wall paintings in the main hall of the treasure house at Horyu-ji Temple

Horyu-ji Temple is the main temple and Buddhist monument in the Horyu-ji area designated a UNESCO world heritage site since 1993. In 1949, the main hall in the Horyu-ji Temple, Nara prefecture, Japan, suffered a fire. Paintings on the burned walls are now stored with other cultural property in the treasure house which has no air conditioning, and doors and windows that are always closed. There is a fear of mold and pest generation due to high relative humidity in the room, so the environment must be controlled to protect the wall paintings from biological damage. Furthermore, Horyu-ji is considering an exhibition of the burned wall paintings in the treasure house, and we therefore need to consider the impact of visitors’ heat and moisture on the generation of mold and pests on the wall. I investigated environmental control methods using a blower in the attic space by numerical analysis. The analysis was performed in two case scenarios. One case involved preserving the walls in a closed treasure house and the other supposed an exhibition. As a result of this analysis, the effect of the reduction of relative humidity using a blower was clarified quantitatively.

Optimization design method of PRHRS air heat exchanger based on natural circulation characteristics

Passive residual heat removal system (PRHRS) was the key equipment to ensure the inherent safety of the fourth generation of nuclear reactors, which can effectively reduce the probability of core meltdown in the event of an accident. A multi-physics coupling model of sodium cooled fast reactor PRHRS was established in this paper, which based on the natural circulation characteristics of PRHRS. The model was analytically calculated according to the flow balance and energy balance, and finally the model was dynamically balanced. The influence of the tube spacing of the serpentine finned tube and the opening area of the air door on the thermal behavior of the system was analyzed through PRHRS model, and the optimal design method of the air heat exchanger (AHX) of PRHRS was mastered. The research results provide a theoretical basis for the rational design of the air heat exchanger and the safe operation of the sodium cooled fast reactor PRHRS.

Oxygen control mechanism in non-ventilation excavation based on the simultaneous mining of coal and gas

A new type of non-ventilation excavation system model, which is based on the theory of simultaneously exploiting coal resources and gas from high-gas coal seams in a closed space, is established, consisting of a central ventilation tunnel and a non-ventilated excavating roadway. The respiration and comfort of the mining personnel, as well as gas control, are investigated. The nitrogen curtain is activated prior to opening the air door to replace the gas in the air perturbation space with nitrogen. The nitrogen curtain is simultaneously activated in the barotropic zone to prevent the flow of oxygen into the excavating roadway. The gas pressure relationship between different zones is studied when the air door is closed. The gas pressure only allows nitrogen to flow from the barotropic zone to the central tunnel zone, which ensures that the oxygen is effectively controlled under the closed air door condition. The proposed mechanism for blocking oxygen in the bypass tunnel is validated via the building analogy simulation and numerical simulation model. The presented non-ventilation excavation design efficiently blocks oxygen via simultaneous control of the air door and nitrogen curtain. This study provides a theoretical foundation for the application of non-ventilation excavation processing.

Modeling and control of mine main fan switchover system

Mine main fan switchover system (MMFSS) is crucial for the mine safe production. MMFSS consists of two main fans (one working and one on standby), and each main fan is equipped with a vertical air door and a horizontal air door. The main purpose of MMFSS is to ensure the stability of the underground airflow quantity and achieve the satisfactory ventilation during the switchover. Moreover, the safe and economic operation of mine production should be ensured. In this paper, the modeling and control problem of MMFSS is considered. First, based on the theory of fluid flow network, the minimal model of MMFSS is built by combining the branch fluid dynamics with the concept of graph theory. Then, a decentralized controller that fully considers the pressure head regulation of two main fans is developed by the Lyapunov stability theory. The controller can ensure that the four air doors can meet with the technological requirements. Finally, the proposed results are conformed using simulations on a semi-physical simulation platform for MMFSS.

Multiple models and neural networks based adaptive PID decoupling control of mine main fan switchover system

Mine main fan switchover system (MMFSS) consists of two main fans, which are equipped with a horizontal air door and a vertical air door, respectively. The purpose of operating MMFSS is to ensure small fluctuation of the underground airflow quantity and to guarantee safe operations of both fans simultaneously by controlling the four air doors during switchover from working to standby fan. MMFSS has time-varying dynamics under different operating conditions, strong coupling, high non-linearities and uncertainty in character, applying conventional control methods can not lead to satisfactory performances. In this study, an adaptive intelligent decoupling proportional–integral–derivative (PID) control method is proposed, where the unmodelled dynamics are estimated and compensated by neural networks, the coupling effect is eliminated by the designed decoupling compensator, and a switching mechanism among multiple models is employed to deal with the effect of time-varying dynamics. By inspiring from the generalised minimum variance control law concept, the parameters of the developed controller are determined. The stability of the close-loop system and the convergence of tracking error are examined. Finally, simulations of MMFSS show the feasibility and effectiveness of the obtained results.

Causes Of Low Efficiency Of Combined Ventilation System In Coal Mines In Resolving The Problem Of Air Leaks (Inflows) Between Levels And Surface

The paper discusses the problem of the underground mining safety control. The long-term air intake to coal accumulations is reviewed as one of the reasons of endogenous fires during mining. The methods of combating air leaks (inflows) in order to prevent endogenous fires are analyzed. The calculations showing the discrepancy between the design calculations for the mine ventilation, disregarding a number of mining-andgeological and mining-engineering factors, and the actual conditions of mining are given. It is proved that the conversion of operating mines to combined (pressure and exhaust) ventilation system in order to reduce the endogenous fire hazard of underground mining is unreasonable due to impossibility of providing an optimal distribution of aerodynamic pressure in mines. The conversion does not exclude the entry of air into potentially hazardous zones of endogenous fires. The essence of the combined application of positive and negative control methods for the distribution of air pressure is revealed. It consists of air doors installation in easily ventilated airways and installation of pressure equalization chambers equipped with auxiliary fans near the stoppings, working sections and in parallel airways.The effectiveness of the combined application of negative and positive control methods for the air pressure distribution in order to reduce endogenous fire hazard of mining operations is proved.

Human evacuation affected by smoke movement in mine fires

The objective of this work is to investigate the influence of smoke movement during mine fires on miner evacuation behaviors. A three-dimensional computational fluid dynamics method was conducted to reconstruct the laneway conveyor belt fire scenes under two ventilating conditions. The parameters, including temperature–time histories, soot density, carbon monoxide and heat release rate, were simulated to characterize the mine fires at various ventilating speeds. A miner evacuation model affected by fire smoke movement was advanced to describe the miner evacuation behaviors, which can be divided into three stages. Based on the evacuation model coupled with the mine fire smoke movement, the available safety evacuation time for miners involved in coal mine fire located in different sites was estimated. Two evacuation patterns were advanced according to the ventilating speeds combined with the model of miner evacuation behaviors. The results show that the miners located between the inlet-air end and the air door in lane 1 should be evacuated to the inlet-air end and other miners involved in coal mine fire could choose the air door as the escaping destination, when the ventilation speed is greater than 3 m/s. Accordingly, the research can be used as references for the mine safety administration authorities to design the safety evacuation.

A investigation of thirdhand smoke pollution in 3 types of places of Nanjing, 2014

To investigate thirdhand smoke (THS) pollution in certain places of Nanjing, as well as to analyze its distribution characteristics. From March to May, 2014, we selected 3 types of places (residencies, public places and transportation vehicles) that were close to people's living in Jianye,Yuhua,Jiangning,Xuanwu,Gulou and Pukou districts of Nanjing city.For each of the above 3 types of places, 2-3 smoking and non-smoking (smoking ban) locations were investigated, totally 51 locations, 9-10 samples were collected each location, totally 477 samples. The surface wipe sampling method in conjunction with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was utilized to quantify the levels of nicotine that served as the tracer of THS pollution.One-way ANOVA and t-tests were employed to compare the levels of nicotine collected at different places and locations. Totally 477 samples were collected in this study, of which 27.0% was from residencies (129/477), 61.0% (291/477) from public places and 11.9% (57/477) from transportations. The levels of indoor surface nicotine in smoking residences, public places and transportations were (214 ± 55),(1 408 ± 177) and (1 511 ± 785) µg/m(2), respectively, which were all higher than those in the corresponding non-smoking places ((23 ± 9),(62 ± 11), and (46 ± 15) µg/m(2); t values were 13.79, 13.15, 3.45, respectively. P values were <0.001, <0.001 and 0.006, respectively).In the smoking places, the levels of surface nicotine on walls, desks, sofas, cabinets, door backsides and air conditioning openings were (171 ± 62),(232 ± 38),(373 ± 151),(903 ± 239), (978 ± 212), (1 721 ± 517) µg/m(2) (F = 7.06, P = 0.009).In the smoking condition, the levels of surface nicotine collected from public places were higher (F = 9.25, P = 0.024), while under non-smoking (smoking ban) conditions, the levels of surface nicotine collected from residences were lower (F = 7.88, P < 0.001). THS pollution was widespread in public places, residences and transportations in Nanjing city, which was more serious in the smoking environments than non-smoking (smoking ban) environments; the contamination was less serious in non-smoking (smoking ban) private residences; in the smoking condition, the levels of surface nicotine were relatively high at locations close to air conditioning openings, door backsides and cabinets.

열적지표를 적용한 국내 고심도 석탄광산의 열환경 평가 연구

본 연구에서는 현장실측을 통하여 강원도 태백에 위치한 대규모 석탄광산의 열환경을 평가하였다. 열환경 평가를 위하여 WBGT, HSI, ESI, KATA지수 및 유효온도 등 다양한 열적지표를 적용하였고, 상관분석을 실시하였다. 분석결과 대부분의 작업장에서 높은 열환경이 평가되었고, 특히 열적지표 중 인체의 생리학적 특성을 반영하는 HSI와 최대 땀증발열의 상관계수는 -0.834이고 이것은 HSI지표에 가장 큰 영향을 미치는 것으로 나타났다. 최대 땀증발열에 가장 큰 영향을 미치는 인자는 공기속도이다. 따라서 운영 중인 제 1수직갱의 연장 굴착 또는 공기 누기를 방지하기 위한 구조물을 설치함으로써 환기량 증대를 통해 작업장의 열환경을 개선시킬 수 있을 것으로 판단된다. In this study, the thermal environment in a large scale coal mine located in Taebaek, Gangwondo was assessed by a field survey. In order to estimate the thermal environment, various heat stress indices such as WBGT, HSI, ESI, KATA index and effective temperature were investigated. Correlation analysis was also conducted. It was found that the thermal environment in most workplace was high. In particular, the correlation coefficient between HSI reflected in physiological fatigue characteristic and the maximum sweat evaporation heat was -0.834. This shows that the correlation coefficient have the most influence on HSI index. The factor which has the most influence on the maximum sweat evaporation heat is velocity of air. The thermal environment of high-depth coal mines is likely to be improved by installing a structure that enables the maximum prevention of extended digging, air doors, or the leakage of the inflow of air in the first shaft.

Designing Home Security and Monitoring System Based on Field Programmable Gate Array*

ABSTRACTIn the conventional design of home security systems, only the property is typically monitored, without taking into consideration the physical control aspects of the house itself. Besides, the term security is not strictly well defined in view of the fact that there is usually a time delay between the alarm system going on and actual arrival of the security personnel. This paper presents the development of a home security and monitoring system that is suitable where the traditional security systems that are mostly concerned about curbing burglary, gathering evidence against trespassing and so on fail. The design and implementation details of this new home control and security system which is based on field programmable gate array has been discussed in the subject paper. The user here can interact directly with the system through a web-based interface over the Internet, while home appliances like air conditioners, lights, door locks, and gates are controlled remotely through a user-friendly web page. An additional feature that enhances the security aspect of the system is its capability to monitor entry points such as doors and windows so that in the event of any breach, an alerting email message could be sent to the home owner instantly.

Temperature adjustment mechanism of composite embankment with perforated ventilation pipe and blocky stone

Based on the advantages of perforated ventilation characteristic of perforated ventilation pipe embankment and large porosity of blocky stone embankment, composite embankment with ventilation pipe and blocky stone is more efficient to protect the underlying permafrost. The temperature fields and cooling effect of composite embankment with air doors are simulated by examining the effects of holes’ position drilled in the pipe, diameter in pipe and density of holes. It is shown that the underlying permafrost temperature obviously reduces by composite methods, the location of 0°C isotherm raises significantly, especially permafrost temperature under the center and shoulder of embankment reduces more quickly, the composite embankment with holes drilled in the lower side of pipe is the most efficient, the increase of diameter has a slight influence on the 0°C isotherm’s raising and the density of holes slightly influences the raising of 0°C isotherm