断面宽度对纵向通风隧道火风压影响研究

针对不同断面宽度隧道中发生火灾时的火风压变化问题，利用Fluent软件模拟隧道内发生火灾的情况，分析隧道宽度对临界风速的影响以及隧道宽度、火源功率和通风速度对火风压的影响。研究表明，火源功率较小时，宽度越小的隧道，临界风速越大；随着火源功率的增大，临界风速之间的差距减小。火风压中火区绕流阻力和热烟摩阻增量会随着风速的增大而相互作用。导致火风压会先随风速的增大而增大，到达一个峰值后会随着风速增大而减小，最后当通风速度增大到临界风速后趋于稳定的数值。随着隧道宽度的增大，通风速率对火风压的影响逐渐减弱。建立不同宽度隧道在不同通风速率和火源功率下的隧道火风压计算公式，为隧道火灾通风设计提供参考。

Research on effect of section width on fire wind pressure in longitudinal ventilation tunnel

Aiming at the change of fire and wind pressure when a fire occurs in tunnels with different cross-section widths, Fluent software is used to simulate the occurrence of fire in the tunnel, and the influence of the tunnel width on the critical wind speed is analyzed, as well as the influence of the tunnel width, fire source power and ventilation speed on fire wind pressure. Research shows that when the power of the fire source is small, the tunnel with a smaller width has a larger critical wind speed; as the power of the fire source increases, the differences between the critical wind speeds decreases. About the fire wind pressure, the two factors, namely, the flow resistance around the fire zone and the increase in hot smoke friction resistance, interact with each other as the wind speed increases. As a result, the fire wind pressure will first increase as the wind speed increases, then decrease as the wind speed increases after reaching a peak value, and finally stabilize when the ventilation speed increases to the critical wind speed. With the increase of tunnel width, the influence of ventilation rate on fire wind pressure decreases gradually. The calculation formulas of tunnel fire wind pressure for different width tunnels under different ventilation rates and fire source power were established, which provided a reference for tunnel fire ventilation design.