Correlations of fire-induced temperature have been reviewed and revisited.The impact of XY factors,i.e.,the relative locations of the fire source and vent,on temperature models of ceiling-vented compartments could be ...Correlations of fire-induced temperature have been reviewed and revisited.The impact of XY factors,i.e.,the relative locations of the fire source and vent,on temperature models of ceiling-vented compartments could be reflected by the exponents of the two dimensionless terms which represent the ratio of the total energy to energy released through the ceiling vent,and the ratio of the energy lost through the walls to the energy released through the ceiling vent.For fires not located directly below the ceiling vent,the temperature rise was proportional to two thirds of the power of the heat release rate,while for fires immediately beneath this vent,the temperature rise was proportional to four thirds the power of the heat release rate,and was inversely proportional to one sixth the power of the ceiling vent size.展开更多
Hermetic pressurized buildings are a new type of building in high-altitude areas that efficiently addresses issues such as high-altitude reactions.The indoor pressure is higher than the external pressure under working...Hermetic pressurized buildings are a new type of building in high-altitude areas that efficiently addresses issues such as high-altitude reactions.The indoor pressure is higher than the external pressure under working conditions,and pressure relief must be carried out first during emergencies.The emergency pressure relief process during a fire may lead to complex fire behavior different from that in regular buildings.In this study,we focus on the impact of ventilation conditions and the status of doors in such buildings on fire evolution and smoke plume characteristics through experiments.The temperature variation in the fire room and corridor is measured under different ventilation power,ventilation time,and door opening width conditions.This shows that the width of the door has the greatest impact on fire development.A smaller gap in the door opening restricts air circulation between the interior and exterior of the room,resulting in a rapid decrease in the oxygen concentration within the fire room and a decrease in the combustion reaction rate of wood fires.The ventilation power exerts the most significant influence on the temperature variation in the corridor.These findings provide empirical data and a basis for fire science studies in high-altitude hermetic pressurized buildings and can guide existing fire protection design and management for improved safety.展开更多
The development of traffic networks in mountainous areas has led to an increasing number of tunnels being constructed in regions of high geothermal activity.This study examined the effects of geothermal temperature,he...The development of traffic networks in mountainous areas has led to an increasing number of tunnels being constructed in regions of high geothermal activity.This study examined the effects of geothermal temperature,heat release rate,and fire source location on temperature distribution and smoke movement in construction tunnel fires through a series of scaled-down experiments.Results showed that geothermal conditions heat the air,creating layered flow within construction tunnels.The temperature and velocity of the induced airflow along the tunnel length were characterized.The upper airflow caused by geothermal conditions hinders the spread of smoke toward the tunnel face,resulting in a complex thermal stratification phenomenon.A model for predicting the smoke diffusion length upstream of the fire source was developed,considering geothermal temperature,heat release rate,and fire source location.Additionally,the ceiling temperature distribution was analyzed,showing that downstream temperature decay is insensitive to fire location,while upstream temperature decay can be divided into geothermal-affected and non-affected zones based on the fire source position.Prediction models for the ceiling temperature distribution upstream and downstream were established,respectively.These findings enhance the understanding of smoke dynamics in construction tunnel fires under high geothermal conditions.展开更多
基金supported by the Anhui Provincial Natural Science Foundation(1408085MKL94)
文摘Correlations of fire-induced temperature have been reviewed and revisited.The impact of XY factors,i.e.,the relative locations of the fire source and vent,on temperature models of ceiling-vented compartments could be reflected by the exponents of the two dimensionless terms which represent the ratio of the total energy to energy released through the ceiling vent,and the ratio of the energy lost through the walls to the energy released through the ceiling vent.For fires not located directly below the ceiling vent,the temperature rise was proportional to two thirds of the power of the heat release rate,while for fires immediately beneath this vent,the temperature rise was proportional to four thirds the power of the heat release rate,and was inversely proportional to one sixth the power of the ceiling vent size.
基金foundation support from the National Natural Science Foundation of China(grant no.72174189,72001095,72304123).
文摘Hermetic pressurized buildings are a new type of building in high-altitude areas that efficiently addresses issues such as high-altitude reactions.The indoor pressure is higher than the external pressure under working conditions,and pressure relief must be carried out first during emergencies.The emergency pressure relief process during a fire may lead to complex fire behavior different from that in regular buildings.In this study,we focus on the impact of ventilation conditions and the status of doors in such buildings on fire evolution and smoke plume characteristics through experiments.The temperature variation in the fire room and corridor is measured under different ventilation power,ventilation time,and door opening width conditions.This shows that the width of the door has the greatest impact on fire development.A smaller gap in the door opening restricts air circulation between the interior and exterior of the room,resulting in a rapid decrease in the oxygen concentration within the fire room and a decrease in the combustion reaction rate of wood fires.The ventilation power exerts the most significant influence on the temperature variation in the corridor.These findings provide empirical data and a basis for fire science studies in high-altitude hermetic pressurized buildings and can guide existing fire protection design and management for improved safety.
基金supported by the National Natural Science Foundation of China(Grant No.52278545)Natural Science Foundation of Hunan Province of China(Grant No.2024JJ2075)+1 种基金the Hunan Traffic Science and Technology Project(Grant No.202510)the Fundamental Research Funds for the Central South University(Grant No.2023ZZTS0416).
文摘The development of traffic networks in mountainous areas has led to an increasing number of tunnels being constructed in regions of high geothermal activity.This study examined the effects of geothermal temperature,heat release rate,and fire source location on temperature distribution and smoke movement in construction tunnel fires through a series of scaled-down experiments.Results showed that geothermal conditions heat the air,creating layered flow within construction tunnels.The temperature and velocity of the induced airflow along the tunnel length were characterized.The upper airflow caused by geothermal conditions hinders the spread of smoke toward the tunnel face,resulting in a complex thermal stratification phenomenon.A model for predicting the smoke diffusion length upstream of the fire source was developed,considering geothermal temperature,heat release rate,and fire source location.Additionally,the ceiling temperature distribution was analyzed,showing that downstream temperature decay is insensitive to fire location,while upstream temperature decay can be divided into geothermal-affected and non-affected zones based on the fire source position.Prediction models for the ceiling temperature distribution upstream and downstream were established,respectively.These findings enhance the understanding of smoke dynamics in construction tunnel fires under high geothermal conditions.
