China Safety Science Journal

Duality of production-related energy objects and mechanism of abnormal release of energy

GUO Hanjun, SU Guofeng, LIN Wei, ZHOU Rui, SUN Zhichun, WANG Yong

2021, 31(4): 1-10. doi:10.16265/j.cnki.issn1003-3033.2021.04.001

Asbtract ( 275 )

PDF (1469KB) ( 283 )

References | Related Articles | Metrics

In order to deepen knowledge about activities of production-related energy and prevent its abnormal release, with typical energy as research example, practical induction and theoretical modelling were combined to reveal activity properties and abnormal release mechanism of such energy. Then, it was categorized by analyzing its characteristics and activity patterns, and constraint and control conditions for safe energy activities were established. Finally, based upon proposed duality of energy objects and related concepts, a theoretical model of production-related energy activities was constructed and applied to analyze abnormal release of various energy. The results show that production systems are composed of energy objects which have duality of energy and matter and are categorized according to factors including their states, activities and work of energy. To ensure safe activities, constraint and control conditions should be satisfied, and failure of such conditions can cause abnormal release of energy.

Safety risk prediction of construction elevator based on database and SVM

ZHAO Tingsheng, PANG Qizhi, JIANG Wenxi

2021, 31(4): 11-17. doi:10.16265/j.cnki.issn1003-3033.2021.04.002

Asbtract ( 231 )

PDF (1552KB) ( 223 )

References | Related Articles | Metrics

In order to prevent safety accidents of construction elevator, database and SVM algorithm were used to predict its safety risks. Firstly, based on relevant theory and characteristics of construction elevators, preliminary theoretical qualitative analysis on their risk factors was carried out. Then, safety accident cases were statistically analyzed by utilizing accident database management system, risk factors were defined and risk prediction indicators were determined. Finally, SVM algorithm was applied to construct a safety risk prediction model, and its parameters were optimized by grid search method, genetic algorithm and particle swarm optimization algorithm respectively to determine the best prediction model. The results show that safety accident database can be used to establish a risk prediction index system, and risk level can be divided by constructing an SVM prediction model, which is helpful for us to take corresponding prevention and control measures to reduce risk of construction elevators, ensure personnel safety, and reduce property losses.

SD model of social stability risk evolution for sensitive water conservancy projects

JIANG Xin, LI Xuelian, WU Jinghan, LI Wei, LUO Dongli, FEI Fan

2021, 31(4): 18-26. doi:10.16265/j.cnki.issn1003-3033.2021.04.003

Asbtract ( 129 )

PDF (2938KB) ( 161 )

References | Related Articles | Metrics

In order to reduce impact of various factors on social stability of local areas during construction of water conservancy projects, their social stability risks were analyzed comprehensively, and importance of risk indicators were determined by using network analytic hierarchy process (ANP). Meanwhile, a SD model of risk evolution for sensitive water conservancy projects was constructed, which included four subsystems, namely public risk perception, projects' inherent risk, government management risk and social environmental risk. Then, these risks were analyzed, and their mutual relations as well as propagation paths were clarified. Finally, an engineering example was adopted for simulation. The results show that public risk perception was confirmed by SD model to be a major factor affecting social stability during construction of sensitive water conservancy projects. Along with increase in safety investment, social stability risks' value will rise first and then fall sharply before they become controllable gradually.

Research on engineering supervision blockchain management pattern in Xiong'an new area and its application

ZHAI Wei, SHENG Zhiping, GUO Xiguang, TONG Ruipeng

2021, 31(4): 27-33. doi:10.16265/j.cnki.issn1003-3033.2021.04.004

Asbtract ( 212 )

PDF (3062KB) ( 192 )

References | Related Articles | Metrics

In order to build an informationized and intelligent project supervision mode in Xiong'an new area, considering current situation of engineering supervision and decentralization characteristics of blockchain technology, a project supervision process based on PDCA was put forward, and a supervision pattern based on blockchain technology was constructed. Furthermore, it was applied in construction projects of Xiong'an new area. The results show that this pattern can better solve long-term construction management problems of Xiong'an new area and contribute to the strategic goal of Xiong'an quality. It helps engineering supervision industry to develop in an accurate, informationalized, automatic and intelligent way, thus promoting innovation in the whole construction project management industry.

Statistics and influencing factors analysis of tunnel gas accidents in China

WANG Haiyang, ZHAO Shulei, CHEN Xiang, WANG Jie, ZHOU Yanmin

2021, 31(4): 34-40. doi:10.16265/j.cnki.issn1003-3033.2021.04.005

Asbtract ( 460 )

PDF (2975KB) ( 539 )

References | Related Articles | Metrics

In order to explore distribution law, development trend and influencing factors of tunnel gas accidents in China, all data of gas tunnels and related accidents in China from 1949 to 2019 were gathered. Then, chart analysis method was used to summarize the accidents, and distribution and development trend characteristics of accident type, accident consequence, occurrence area and timing were summed up. Finally, influencing factors of 8 typical tunnels which witnessed accidents at various levels were analyzed by grey correlation method. The results show that tunnel gas accidents majorly distribute in southeastern China while other regions have less. And the main accident type is gas explosion which leads to the severest consequences. It is also found that key influence indexes of tunnel gas accidents include gas content in surrounding rock, stratum lithology, geological structure, groundwater exposure degree and buried depth of tunnels in turn.

Vulnerability assessment of runway intrusion risk control network based on SD model

WU Wei, LUO Xinran, WEI Ming

2021, 31(4): 41-48. doi:10.16265/j.cnki.issn1003-3033.2021.04.006

Asbtract ( 161 )

PDF (2099KB) ( 165 )

References | Related Articles | Metrics

In order to quantify risks of runway intrusion, and to evaluate vulnerability characteristics of core factors in risk control network, a SD model was constructed to systematically study runway intrusion by using vulnerability theory. Firstly, according to incursion cases and expert experience, causal factors were identified, their relevancy degree was analyzed by adopting grey correlation theory, and core control elements were determined. Secondly, interaction mechanism between elements was analyzed, a SD model was established, and dynamic equations were designed by utilizing Bayes theory and comprehensive weight determination method. Finally, vulnerability of runway intrusion risk control network was defined through simulation and analysis, and its resilience was improved through combination strategy analysis. The results show that Bayesian theory and comprehensive weight determination method, combined with historical data, can effectively improve objectivity and accuracy of SD model. Controller's un-timely instructions, increasing rate of communication breaking, fast growth of traffic and reduced regulatory investment are vulnerable points of the network. And risk control strategies, such as intensified training and experience and increasing personnel allocation and equipment update, have obvious substitution on improving network resilience, yet effect of strengthening supervision strategy will be suppressed under large traffic condition.

Influence of job insecurity on miners' safety performance: based on perspective of intergenerational difference

YI Tao, LI Jizu

2021, 31(4): 49-56. doi:10.16265/j.cnki.issn1003-3033.2021.04.007

Asbtract ( 224 )

PDF (1400KB) ( 273 )

References | Related Articles | Metrics

In order to improve level of coal mine safety management and improve miners' safety performance, a hypothetical model of relationship between job insecurity, organizational commitment, safety performance and generational differences was established based on theoretical analysis and perspective of intergenerational difference. Valid data of 476 front-line miners were collected through questionnaire survey, direct effect was analyzed using structural equation model, and mediating effect of organizational commitment and moderating effect of intergenerational difference were detected. The results show that job loss insecurity, execution insecurity, and interpersonal insecurity negatively affect safety performance and organizational commitment. Organizational commitment has a significant positive effect on safety performance and plays an utterly mediating role between job insecurity and safety performance. Intergenerational difference effect is substantial, compared with the older generation of miners, the new generation of miners' organizational commitment is more significantly negatively affected by job execution insecurity. However, negative impact of job loss insecurity and interpersonal insecurity on safety performance is weaker.

Study on influencing factors of cracking radius range caused by liquid CO₂ phase transition in coal seams

JIA Jinzhang, LI Bin, WANG Dongming

2021, 31(4): 57-63. doi:10.16265/j.cnki.issn1003-3033.2021.04.008

Asbtract ( 153 )

PDF (2970KB) ( 262 )

References | Related Articles | Metrics

In order to improve efficiency of gas drainage of coal seam and reduce accident of mine gas disasters, grasping characteristics of influence of different factors on cracking radius of liquid CO₂ phase change. Based on equivalent conversion of TNT released by liquid CO₂ gas explosion energy, evolution model of coal blasting damage was established. LS-DYNA software was used to simulate physical properties of coal seams(coal in-situ stress σ, coal tensile strength S_t, gas pressure P_g)and influence of pore size d on fracturing radius L of liquid CO₂ phase change. Primary and secondary order of blasting influencing factors was analyzed by using grey-relational-analysis theory. The results show that liquid CO₂ phase change fracturing radius has a positive relationship with gas pressure and borehole diameter, and has a negative relationship with coal seam in-situ stress. In-situ stress has the greatest influence on fracturing radius and borehole diameter has a strong influence on fracturing radius and gas pressure has a slight influence, change of coal tensile strength has little effect on fracturing radius range.

Self-protection pressure relief mechanism and prevention and control of rock burst in near-vertical coal seams

OUYANG Zhenhua, ZHOU Xinxin, SUN Bingcheng, YI Haiyang, LIU Xudong, ZHOU Ranran

2021, 31(4): 64-71. doi:10.16265/j.cnki.issn1003-3033.2021.04.009

Asbtract ( 147 )

PDF (3920KB) ( 131 )

References | Related Articles | Metrics

In order to effectively prevent and control pressure bumping during mining of near-vertical extra-thick coal seam group, take south mining area of Wudong coal mine in Urumqi mining area as research object, impact reason of 87° near-vertical super thick coal seam group was analysed , key and difficult points of rock burst prevention and control of this kind of coal seam was explored,self-protection pressure relief prevention and control method were put forward , and pressure relief and impact prevention effect of this method was analysed. The research shows that rock burst of near-vertical coal seam group mainly occurs in the first coal seam. Main reason is that roadway is located in the high stress area caused by superposition of abutment pressure and horizontal tectonic stress, which enhanced rock burst risk. Taking self protective pressure relief measures for the first coal seam can not only change stress environment of coal and rock mass, transfer the high stress area generated by superposition of abutment pressure and horizontal tectonic stress to deep coal and rock mass, place roadway of mining face in the low stress area, but also change properties of coal and rock, and make it lose possibility of gathering a lot of elastic properties, so as to prevent occurrence of pressure bumping.

Joint optimization of key parameters of transverse seismic isolation system for cable-stayed bridge with unequal height pylons

ZHAO Guohui, PAN Youdong

2021, 31(4): 72-80. doi:10.16265/j.cnki.issn1003-3033.2021.04.010

Asbtract ( 126 )

PDF (3006KB) ( 191 )

References | Related Articles | Metrics

In order to explore influence of key parameters of transverse seismic isolation system, which consisted of steel dampers and anti-wind supports, on transverse seismic response of cable-stayed bridges, taking a cable-stayed bridge with unequal height pylons as an example, orthogonal test design method was used to set analysis conditions for joint optimization of parameters based on balance principle between structural internal force and displacement response. Then, internal force and displacement response, and energy dissipation of steel dampers were set as optimized indexes, and influence of steel dampers' yield force and anti-wind supports' initial clearance on these indexes was studied. The results show that significant parameter coupling effect is observed from internal force of auxiliary pier and displacement response of side-span beam end at higher pylon side, so joint optimization should be considered. Moreover, internal force and displacement response can be significantly decreased by setting steel dampers on abutments and piers, but not the internal force response of pylons.

Research on distance influenced by a jet engine based on improved DES method and SA model

HE Xin, HU Dengfeng, LIU Cheng, MA Yilong

2021, 31(4): 81-87. doi:10.16265/j.cnki.issn1003-3033.2021.04.011

Asbtract ( 106 )

PDF (3243KB) ( 132 )

References | Related Articles | Metrics

In order to evaluate influence range and degree of take-off aircraft engine jet and analyze feasibility of rear traverse scheme, influence distance of take-off aircraft engine jet under rear traverse mode was numerically simulated based on SA turbulence model combined with DES method. A high subsonic nozzle model was selected for numerical simulation, and simulation results were compared with reference values in literature to verify correctness and effectiveness of method. On this basis, combined with actual boundary conditions of B737-800 engine, numerical simulation of jet effect of engine was carried out, and influence distance of jet of B737-800 engine was obtained, and accuracy was verified by comparing with aircraft characteristic manual. The results show that influence distance of jet flow at 44, 22 and 16 m/s can be obtained by numerical simulation of B737-800 engine with improved DES method combined with SA model.

Study on minimum ignition energy of H₂/CO syngas

LI Chang, YUAN Yixiao, YUAN Qi, HAO Jiantao, HE Wei, YUAN Chunmiao

2021, 31(4): 88-94. doi:10.16265/j.cnki.issn1003-3033.2021.04.012

Asbtract ( 164 )

PDF (2125KB) ( 307 )

References | Related Articles | Metrics

In order to explore minimum ignition energy variation characteristics of industrial syngas (mainly composed of H₂ and CO) under action of volume fraction and inerting effect. Firstly, methane gas was used to determine sensitive conditions of experimental system of minimum ignition energy. Then, minimum ignition energy of H₂/CO syngas with different ratios, as well as N₂ dilution conditions was measured by using a calibrated experimental device under its sensitive conditions. Finally, minimum ignition energy of gas mixture under N₂ dilution was determined. The result shows that in H₂ and CO syngas without inert gas, when volume fraction of H₂ is lower than 25%, it has a great influence on sensitive volume fraction value of system syngas. In H₂ and CO syngas containing N₂, inerting effect is significant when fuel volume fraction is greater than 40%. When fuel volume fraction of H₂ and CO syngas containing inert gas N₂ is less than 40%, contribution of system's minimum ignition energy value mainly depends on volume fraction of H₂.

Evaluation method for safety of subway tunnels adjacent to deep foundation pits

ZHANG Qi, WANG Yuefeng, LI Jianchun, ZHANG Bin, XU Jiang

2021, 31(4): 95-104. doi:10.16265/j.cnki.issn1003-3033.2021.04.013

Asbtract ( 201 )

PDF (1692KB) ( 193 )

References | Related Articles | Metrics

In order to assess safety status of subway tunnels adjacent to deep foundation pits during their excavation, an evaluation method based on rough sets and Mamdani fuzzy inference was proposed. Firstly, three first-level impact indicators, including conditions of subway tunnels, engineering geological conditions and support conditions of deep foundation pits, and eight secondary indexes, such as tunnel settlement, tunnel convergence, tunnel distance, rock and soil shear resistance index, groundwater level, supporting structure thickness and insertion ratio of enclosing structure were summarized, and their evaluation criteria were determined. Then, discretization, reduction, and equivalence class division based on rough set theory were conducted to obtain a relatively objective weight vector. Finally, the weight vector was put into Mamdani fuzzy inference, and an accurate evaluation score was obtained through mapping. The results show that accurate safety status score of subway tunnels adjacent to deep foundation pits under influence of multiple index factors can be obtained through safety evaluation method based on rough set theory and Mamdani fuzzy inference.

Study on characteristic parameters of oil pool fire of different diameters in low pressure environment

LIU Quanyi, ZHU Bo, DENG Li, LYU Zhihao, HU Lin, LIANG Guanghua

2021, 31(4): 105-110. doi:10.16265/j.cnki.issn1003-3033.2021.04.014

Asbtract ( 242 )

PDF (1786KB) ( 240 )

References | Related Articles | Metrics

In order to explore development characteristics, HRR and fire hazard of oil pool fire in low pressure environment, n-heptane and aviation kerosene combustion experiments for oil pool of different diameters were carried out based on full-scale low-pressure HRR test platform. Characteristic parameters of oil pool fire were measured, including heat flux density, HRR and gas concentration. Then, effects of pool diameter on these parameters were analyzed. The results show that when distance between heat flow meter and oil pool is constant, heat flux density increases with increasing diameter, but decreases with increase of distance when the diameter is constant. Combustion heat of n-heptane is greater than aviation kerosene as the diameter is 10-20 cm while that of the latter is greater when it is more than 30 cm. Moreover, combustion of n-heptane produces more CO₂ than the other and burns more fully at the same time.

Calculation methods and visualization for coverage area of communication and navigation facilities in plateau region

SONG Tao, XIA Zhenghong, WAN Jian, ZHU Xinping, LI Yang

2021, 31(4): 111-118. doi:10.16265/j.cnki.issn1003-3033.2021.04.015

Asbtract ( 117 )

PDF (2059KB) ( 209 )

References | Related Articles | Metrics

In order to improve calculation precision of effective coverage area and support capacity of communication and navigation facilities in complex terrain of plateau region, strict algorithm for operation range of space wave and iterative algorithm for determination of obstacle shelter points were proposed. With consideration to comprehensive influence of various factors, including elevation of transmitting and receiving terminals, the position and elevation of obstacles and the curvature of the earth, these algorithms, by designing computer programs, could precisely resolve maximum transmission distance of electromagnetic wave and achieve accurate calculation and visual analysis for coverage area of ground-based communication and navigation facilities in complex terrain of plateau region. The results show that the proposed strict algorithm can improve calculation precision of maximum range of electromagnetic wave while iterative algorithm can accurately define position of obstacle shelter points which have a direct impact on the maximum transmission distance, thus improving credibility of calculation results. Moreover, visualization calculation software developed according to algorithms above and combined with CAD technology can precisely calculate and automatically map actual guarantee range of related air lines around facilities in plateaus.

Analysis and safety monitoring of multi-span reticulated shell construction platform

WU Yilin, CHEN Xiaoming, ZHOU Feng, JIN Weifeng, YU Aiyan, WANG Zhengjia

2021, 31(4): 119-124. doi:10.16265/j.cnki.issn1003-3033.2021.04.016

Asbtract ( 109 )

PDF (5322KB) ( 144 )

References | Related Articles | Metrics

In order to ensure structure safety and stability during construction process, process analysis was used to simulate construction of a multi-span reticulated shell structure. Then, based on simulation results, representative components were selected as measuring points to monitor stress changes due to structural system, force transmission path, load conditions and boundary conditions during whole process. Finally, results of numerical simulation were compared with actual measurement to predict possible accidents. The results show that measured values can reflect stress changes of structures during system transformation, and verify correctness of stress monitoring system and methods. Therefore, stress monitoring based on construction process analysis can predict possible risks during construction.

Research on early warning of coal and gas outburst microseismic-gas interactive response

LONG Nengzeng,YUAN Mei,WANG Guanliang,WANG Qinghui,XU Shiqing,LI Xinling

2021, 31(4): 125-132. doi:10.16265/j.cnki.issn1003-3033.2021.04.017

Asbtract ( 215 )

PDF (2388KB) ( 179 )

References | Related Articles | Metrics

In order to solve problem of high false alarm rate of coal and gas outburst real-time early warning technology in the field, main controlling factors and precursor characteristics of coal and gas outburst in driving face of a mine in Guizhou Province were analyzed, and real-time early warning mechanism of microseismic-gas interactive response was studied. An intelligent prediction model for coal and gas outburst based on data mining was established, principles for dividing risk levels of coal and gas outbursts were defined, a real-time warning system for coal and gas outburst hazard was established. Coal and gas outburst risk grade was predicted by using measured data of heading face.The results show that prediction accuracy of intelligent prediction model is relatively high, and prediction results are in good agreement with drilling cutting-gas desorption index K₁ value and gas pressure value P. Warning level of established warning system is basically consistent with actual coal and gas outburst risk on working face.

Research progress on disaster effect of combustible gas explosion in long straight space

CAI Jiongwei, YANG Shigang, SUN Wensheng, YANG Ya, WANG Jian

2021, 31(4): 133-140. doi:10.16265/j.cnki.issn1003-3033.2021.04.018

Asbtract ( 172 )

PDF (1400KB) ( 210 )

References | Related Articles | Metrics

In order to systematically study research results on disaster effect of combustible gas explosion, general steps for disaster consequence assessment were summarized based on characteristics of such explosion in long straight space. Then, theoretical calculating model, experimental research and numerical simulation results of combustible gas explosion load were discussed, and research progress on structural dynamic response and consequence assessment of explosion was explored. The results show that most of existing empirical formulas of gas explosion load, with their own range of application, are not universal. Test data concerning dynamic response of explosion structure in long straight space are few, and research results on pressure vessels are of limited value to study it. Moreover, standards of building and personnel damage under explosion shock wave have not been unified.

Design and application of a fire detection and early warning robot in construction site

LI Jichao, GUO Shengyu, KONG Liulin, YUAN Yican, SUN Yang

2021, 31(4): 141-146. doi:10.16265/j.cnki.issn1003-3033.2021.04.019

Asbtract ( 241 )

PDF (3988KB) ( 299 )

References | Related Articles | Metrics

In order to prevent fire accidents at construction sites and improve fire detection performance, a detection and early warning robot based on combination of SSD and MobileNet model was designed. Firstly, data set of collected fire video images was processed and divided into two categories, namely real fire images and non-fire images. Secondly, network parameter values in SSD_MobileNet model were fine-tuned based on idea of migration learning. Finally, the obtained model was integrated into robot video surveillance platform for fire detection and early warning, and its application effect was tested on a construction site. The results show that the robot can accurately detect fire in construction sites with a 50% confidence threshold of detection model. Accuracy of multi-frame video exceeds 90%, and real-time warning can be achieved.

Influence of dust source location in fully-mechanized excavation face on location of negative pressure suction opening

ZHANG Yanjiao, XU Xiangyu, JIANG Wan , YAO Longlong

2021, 31(4): 147-155. doi:10.16265/j.cnki.issn1003-3033.2021.04.020

Asbtract ( 158 )

PDF (7732KB) ( 126 )

References | Related Articles | Metrics

In order to study influence of suction opening location of integrated excavating machine on dust removal effect of roadway, a similar geometric model of roadway was established by using FLUENT software, and simulated researches on flow field and dust field of press-fit ventilation system and dust extraction system of integrated excavating machine were developed when dust was released from different dust sources.The results show that dust diffusion range of press-fit ventilation system of fully mechanized excavation face is 1-2 m away from head. Wind flow characteristics of suction location of integrated excavating machine at 1 m from head are most favorable for dust removal, and position of each dust source at this time dust in the roadway has been significantly improved. Dust extraction experiment of integrated excavating machine has also verified simulation results well. After adopting dust extraction technology of comprehensive excavator, overall dust concentration in the roadway is reduced when dust is released from various dust sources in the fully mechanized excavation face, and average dust removal efficiency is above 80%, up to 93%, which can well meet the dust reduction requirements of coal mines.

Study on fire-induced smoke temperature distribution characteristics in largely inclined roadway

LIU Yuqing, ZHANG Peihong

2021, 31(4): 156-162. doi:10.16265/j.cnki.issn1003-3033.2021.04.021

Asbtract ( 150 )

PDF (1981KB) ( 221 )

References | Related Articles | Metrics

In order to study fire smoke distribution features in inclined mine roadway with longitudinal ventilation, maximum temperature and longitudinal attenuation characteristics beneath ceiling in a roadway with slope ranging from 5° to 30° were analyzed through Pyrosim numerical simulation method. Then, slope correction coefficients were put forward, and a new prediction model of maximum smoke temperature beneath ceiling with slope greater than 10° was established. The results show that with increase of roadway slope, maximum smoke temperature decreases, but temperature rising gradient in vertical direction decreases, and roadway near fire source is filled with hot smoke. Temperature attenuation characteristics along downwind ceiling of fire source can be correlated well by sum of two exponential functions. Longitudinal smoke temperature distribution downstream fire source with large roadway slopes can be divided into two regions. When dimensionless longitudinal distance x/H is smaller than 5, smoke temperature decreases along with increase of distance as slope increases. In case of x/H greater than 5, the greater roadway slope is, the higher smoke temperature is when slope is larger than 10°, however as it is within 10°, the greater it is, the lower temperature will be.

Experimental study on thermal instability of imidazolium ionic liquids

WANG Gan, ZHENG Zhongyu, DUAN Weijia, PAN Yong

2021, 31(4): 163-170. doi:10.16265/j.cnki.issn1003-3033.2021.04.022

Asbtract ( 286 )

PDF (2382KB) ( 422 )

References | Related Articles | Metrics

In order to further clarify thermal behavior of ionic liquids, experimental study was performed on their thermal instability, such as thermal decomposition and flashover, under heated conditions. Synchronous thermal analyzer and closed flash point tester were used to measure thermal decomposition temperature of 16 kinds of imidazolium ionic liquids and flash temperature of 50 kinds of them. The results show that flash temperature of imidazolium ionic liquids is related to structures and types of anions and cations with the former exerting a greater impact, and it is also affected by interaction between them, which stands for geometrical structure, size and charge distribution of ions. Moreover, there is no obvious sequence between flashover and thermal decomposition of imidazolium ionic liquids after heating, and flashover happens when combustible products generated from decomposition meet ignition sources.

Experimental study on flame merging behavior of spilled flame generated by flame impinging on obstruction

XING Chaoliang, HUANG Xianjia, HE Le, ZHU He, ZHENG Zeming

2021, 31(4): 171-176. doi:10.16265/j.cnki.issn1003-3033.2021.04.023

Asbtract ( 213 )

PDF (5205KB) ( 197 )

References | Related Articles | Metrics

In order to further study cable fire of multi-layer horizontal cable tray in nuclear power plants, a series of tests for spilled flame merging caused by flame impinging on obstruction were carried out. Experiments were conducted for HRR at 10, 14, 28, 42, 56 and 84 kW and distance between plate and burner at 0.1, 0.2, 0.3, 0.4 and 0.5 m. Then, figure of flame intermittence probability under different conditions were compared and analyzed, and flame merging probability was introduced to describe merging phenomenon. It was found that such behavior can be quantitatively divided according to ratio of HRR to distance between plate and burner. When the ratio is less than 200, it is a non-merging zone as spilled flame does not merge. As the ratio is larger than 600, it will merge constantly, thus a constant-merging zone while between 200 and 600, it merges intermittently, therefore an intermittent-merging zone.

Fault risk assessment of sliding plug door of EMU based on fuzzy interval TOPSIS

MA Run, QIU Weibin, QIN Yun, OU Hongxiang

2021, 31(4): 177-183. doi:10.16265/j.cnki.issn1003-3033.2021.04.024

Asbtract ( 212 )

PDF (1788KB) ( 245 )

References | Related Articles | Metrics

In order to improve operation reliability of sliding plug door of EMU, fuzzy analytic hierarchy process (AHP) was used to calculate seven main fault modes and weight of fault causes.Fuzzy theory was introduced to evaluate cause of failure from three risk indexes, failure incidence, maintenance cost and failure operation delay. Multi-attribute risk indexes of each fault cause were evaluated and weighted risk evaluation matrix was obtained. TOPSIS was used to calculate relative nearness of fault mode, and result of risk assessment was obtained. The results show that calculated results are consistent with field maintenance records of plug door in recent 2 years. Failure of lock device, limit switch and sensitive edge fault have great harm to operation reliability of plug door of EMUS, need key overhaul and maintenance.

Risk and cost based emergency control decision-making for offshore oil spills

LI Xinhong, ZHANG Yi, HAN Ziyue, JIA Ruichao, WANG Jingwen, ZHU Yujiao

2021, 31(4): 184-190. doi:10.16265/j.cnki.issn1003-3033.2021.04.025

Asbtract ( 171 )

PDF (1582KB) ( 286 )

References | Related Articles | Metrics

In order to make more scientific emergency decision for offshore oil spills and effectively reduce offshore ecological environment risk caused by such accidents, a risk and cost based emergency decision-making methodology was proposed, and main variables and time sequence nodes in escalation of offshore oil spills were identified. Then, an evolution model of accidents was established based on Bayesian network to assess ecological environment risk they caused. On such basis, by introducing emergency measures and considering execution cost and effect of different disposal measures, a Bayesian influence diagram model for emergency control of offshore oil spills was developed, which could determine an effect-and-cost-optimal emergency control strategy. The results show that a combination of sea surface burning and natural recovery is the best solution for oil spill disposal in real cases, which could effectively reduce risk and control cost.

Table of Content