Study on smoke stratification stability in inclined tunnel fire
The smoke stratification characteristics in the tunnel play an important role in analyzing the difficulty of evacuation and rescue and formulating effective emergency strategies.The smoke flow in inclined tunnels is affected by both buoyancy and stack ef-fect,resulting in significant differences in the distribution and movement of smoke between inclined tunnels and horizontal tun-nels.In inclined tunnels,the stability of smoke stratification is af-fected by many factors,and there are few related studies.In this paper,the numerical simulation method is used to study the smoke distribution characteristics and its influencing factors of in-clined tunnel fires with openings at both ends with an inclination angle of 1%～15%.The research shows that the critical dimen-sionless temperature difference proposed by Newman to deter-mine the stratification state of smoke is still applicable in inclined tunnel fires(the slope is within the range of 1%～15%).After the fire in the inclined tunnel,the smoke layer between the fire source and the low-end entrance can always maintain a stable smoke stratification.The smoke layer between the fire source and the high-end outlet increases with the chimney effect,and the area where the stable stratification is destroyed continues to expand and gradually expands to the entire downstream area.The fire source power and the height difference between the fire source and the high-end outlet can directly affect the stack effect in the tunnel and the smoke buoyancy,thus affecting the smoke stratifi-cation state.On this basis,a calculation model for predicting the smoke stratification characteristics of inclined tunnel fires is pro-posed,and the critical Froude number between zone 1 and zone 2 is determined to be 0.9.The research conclusions can provide use-ful reference for tunnel fire smoke exhaust and evacuation design.
inclined tunnelsmoke stratificationstack effectFroude number
万方数据
维普
