Tbe experimental simulation has been performed to investigate the smoke flowing properties within the 1/5 reduced-scale model of a sleeping carriage. The velocity field of the running train on fire is simulated in a w...Tbe experimental simulation has been performed to investigate the smoke flowing properties within the 1/5 reduced-scale model of a sleeping carriage. The velocity field of the running train on fire is simulated in a wind tunnel of the State Key Lab of Fire Science, USTC (University of Science & Technology of China). In this paper, the fire-smoking properties and the variation of the temperature field in the sleeping carriage are analyzed. This paper introduces the simulation method of reducedscale experiment about the running train and the analysis or the experimental data. It provides the basis of experiment for the running train’s fire-safety and full-scale experiment in the future study.展开更多
Understanding the characteristics of smoke flow in tunnel fire is very important for tunnel safety. The characteristics of tunnel fire were analyzed. The smoke development in different situations of an engineering exa...Understanding the characteristics of smoke flow in tunnel fire is very important for tunnel safety. The characteristics of tunnel fire were analyzed. The smoke development in different situations of an engineering example was simulated using commercial CFD software PHOENICS 3.5 by field modeling method. The spreading rules and characteristics of concentration field and temperature field of smoke flow with different longitudinal ventilation speeds were studied, which may provide the theoretical background for evacuation design in tunnel fire. The effective measures of fire rescue and crowd evacuation were also described.展开更多
This study applied the numerical simulator tool FDS （fire dynamics simulator）, Version 5.53, and focused on the simulation of the natural smoke flow ventilation design system, an innovative ventilation design using ...This study applied the numerical simulator tool FDS （fire dynamics simulator）, Version 5.53, and focused on the simulation of the natural smoke flow ventilation design system, an innovative ventilation design using the parallel processing technology MPI （message passing interface）. The design was then compared with the exhaust efficiency of a typical natural smoke vent. The natural smoke flow ventilation design system was located at the top of the factory, where smoke streams effectively converged. Therefore, the source of fire was designed to be 2 MW, which has a better exhaust efficiency than typical natural smoke vent with same area. The simulation discovered that the exhaust efficiency of the natural smoke ventilation design systems is higher than that of typical natural smoke vent with 2 times the opening area and that was not affected by external wind speed, Instead, external wind speed can help to enhance the exhaust efficiency. Smoke exhaust of typical natural smoke vents was affected by external wind speed, even leading them to become air inlets which would disturb the flow of air indoors, leading to smoke accumulation within the factory.展开更多
Real-time wild smoke detection utilizing machine based identification method is not produced proper accuracy,and it is not suitable for accurate prediction.However,various video smoke detection approaches involve mini...Real-time wild smoke detection utilizing machine based identification method is not produced proper accuracy,and it is not suitable for accurate prediction.However,various video smoke detection approaches involve minimum lighting,and it is required for the cameras to identify the existence of smoke particles in a scene.To overcome such challenges,our proposed work introduces a novel concept like deep VGG-Net Convolutional Neural Network(CNN)for the classification of smoke particles.This Deep Feature Synthesis algorithm automatically generated the characteristics for relational datasets.Also hybrid ABC optimization rectifies the problem related to the slow convergence since complexity is reduced.The proposed real-time algorithm uses some pre-processing for the image enhancement and next to the image enhancement processing;foreground and background regions are separated with Otsu thresholding.Here,to regulate the linear combination of foreground and background components alpha channel is applied to the image components.Here,Farneback optical flow evaluation technique diminishes the false finding rate and finally smoke particles are classified with the VGG-Net CNN classifier.In the end,the investigational outcome shows better statistical stability and performance regarding classification accuracy.The algorithm has better smoke detection performance among various video scenes.展开更多
文摘Tbe experimental simulation has been performed to investigate the smoke flowing properties within the 1/5 reduced-scale model of a sleeping carriage. The velocity field of the running train on fire is simulated in a wind tunnel of the State Key Lab of Fire Science, USTC (University of Science & Technology of China). In this paper, the fire-smoking properties and the variation of the temperature field in the sleeping carriage are analyzed. This paper introduces the simulation method of reducedscale experiment about the running train and the analysis or the experimental data. It provides the basis of experiment for the running train’s fire-safety and full-scale experiment in the future study.
基金Project(20033179802) supported by the Science and Technology Program of China Western Transportation Development
文摘Understanding the characteristics of smoke flow in tunnel fire is very important for tunnel safety. The characteristics of tunnel fire were analyzed. The smoke development in different situations of an engineering example was simulated using commercial CFD software PHOENICS 3.5 by field modeling method. The spreading rules and characteristics of concentration field and temperature field of smoke flow with different longitudinal ventilation speeds were studied, which may provide the theoretical background for evacuation design in tunnel fire. The effective measures of fire rescue and crowd evacuation were also described.
文摘This study applied the numerical simulator tool FDS （fire dynamics simulator）, Version 5.53, and focused on the simulation of the natural smoke flow ventilation design system, an innovative ventilation design using the parallel processing technology MPI （message passing interface）. The design was then compared with the exhaust efficiency of a typical natural smoke vent. The natural smoke flow ventilation design system was located at the top of the factory, where smoke streams effectively converged. Therefore, the source of fire was designed to be 2 MW, which has a better exhaust efficiency than typical natural smoke vent with same area. The simulation discovered that the exhaust efficiency of the natural smoke ventilation design systems is higher than that of typical natural smoke vent with 2 times the opening area and that was not affected by external wind speed, Instead, external wind speed can help to enhance the exhaust efficiency. Smoke exhaust of typical natural smoke vents was affected by external wind speed, even leading them to become air inlets which would disturb the flow of air indoors, leading to smoke accumulation within the factory.
文摘Real-time wild smoke detection utilizing machine based identification method is not produced proper accuracy,and it is not suitable for accurate prediction.However,various video smoke detection approaches involve minimum lighting,and it is required for the cameras to identify the existence of smoke particles in a scene.To overcome such challenges,our proposed work introduces a novel concept like deep VGG-Net Convolutional Neural Network(CNN)for the classification of smoke particles.This Deep Feature Synthesis algorithm automatically generated the characteristics for relational datasets.Also hybrid ABC optimization rectifies the problem related to the slow convergence since complexity is reduced.The proposed real-time algorithm uses some pre-processing for the image enhancement and next to the image enhancement processing;foreground and background regions are separated with Otsu thresholding.Here,to regulate the linear combination of foreground and background components alpha channel is applied to the image components.Here,Farneback optical flow evaluation technique diminishes the false finding rate and finally smoke particles are classified with the VGG-Net CNN classifier.In the end,the investigational outcome shows better statistical stability and performance regarding classification accuracy.The algorithm has better smoke detection performance among various video scenes.
