Behavior of hot airflow heated by a fire in a tunnel with ventilation duct.

本年度进行的实验结果如下：模拟风道隧道火灾中气流温度和运动的测量。通过在模型风道中增加测点数量，进行了一系列隧道火灾实验，以精确测量气流温度。用烟管观察正常温度区和高温区的气流。当风管倾斜度较小时，风管两侧都有空气流入和流出，即热空气从风管上部流出，冷空气从风管下部流入。当倾斜度较大时，只观察到下部有气流流入。火场下风处的温度存在不连续性，气流受到高度扰动。斜井实际尺寸火灾试验。在九州煤矿研究中心资源环境研究所的斜井中进行了实际尺寸的火灾实验。在逆风和顺风条件下，观察了火加热热气流的行为。即使在火灾过程中，当初始风速大于1.7m/s时，气流仍继续向下流动。这是预料不到的结果，但对今后利用不同的倾斜度进行隧道火灾试验具有重要的指导意义。开发模拟隧道火灾的计算机程序，开发该程序是为了能够模拟气体扩散和排气通风系统。但是，它需要解决计算时间长和内存需求大的问题。

The results of experiments executed in this year are as follows.1. Measurement of airflow temperature and movement during a tunnel fire in a model duct.A series of tunnel fire experiments are executed to measure precise airflow temperatures by increased number of measuring points in a model duct. Airflow in a normal and hot temperature zone was visualized by a smoke tube. There were air inflow to and outflow from the duct at the both sides of the duct when the inclination of the duct was small, that is, heated air came out at the upper part of the duct and cold air flew in at the lower part of the duct. There observed only inflow of air at the lower side of the duct when the inclination was large. There ware discontinuity in the air temperature at the downwind of the fire and highly disturbed air flow was also observed by the visualization.2. Actual size fire experiments in an inclined shaft.Actual size fire experiments were executed in an inclined shaft at the National Institute of Resources and Environment, Kyushu Coal Mining Research Center. Behavior of hot airflow heated by a fire was observed during upwind and downwind conditions. The airflow continued to flow downward even during the fire when initial air velocity was more than 1.7m/s. This result was not expected one, however, it will be very useful if another tunnel fire experiments will be done using different inclination.3. Development of a computer program to simulate a fire in a tunnelThe program was developed to be able to simulate gas diffusion and exhaust ventilation system. However, it requires to resolve the long computation time and large memory requirement.