隧道墙附近火源火灾热气流的计算流体动力学

运用CFD进行数字模拟，以了解纵向通风隧道内热烟气流的特性。通过模拟发现对火源进行模拟非常重要，热烟气流特性受火源位置的影响很大，并且对火源模拟方法很敏感。火源生成的火焰区是燃烧引起的化学反应区域。即使火源附近的木垛排列完好，也很难在考虑这些化学反应条件下模拟热生成区域。建议考虑纵向通风隧道内火焰形状并对它进行数字模拟。模拟结果与试验结果非常吻合。试验证明，在纵向通风隧道内，热烟气流从靠近墙体火源处顺风向隧道中心蔓延。数字模拟结果发现，火灾羽流造成的螺旋上升空气会在墙体和羽流之间形成一个涡流区。

Computational fluid dynamics of hot current from a fire source near a tunnel wall

Numerical simulation by CFD was carried out to understand the hot current behavior in a tunnel with longitudinal ventilation. It becomes clear that fire source modeling is very important because the hot current behavior is strongly affected by the fire source position and is sensitive to methods in the modeling of the fire source. The flame area which has developed from the fire source is an area of chemical reaction caused by combustion. Even if grids in the vicinity of the fire source are made fine, it was difficult to simulate the heat generation area with consideration to this chemical reaction through using a method for setting the heat release rate simply on the fire source surface. Therefore, we proposed a method adopting the knowledge on flame shape under the longitudinal ventilation and incorporating it into numerical simulation and it showed a good agreement with the experimental results. It was shown through experiments in a tunnel with longitudinal ventilation that the hot current developed toward the tunnel center downwind from the fire source near a wall. The cause was investigated by numerical simulation and it became clear from the results that the spiral air by the fire plume created a vortex in the crevice between the wall and the plume.