Simulation of fire in subsurface space

本年度进行的实验结果如下。聚甲基丙烯酸甲酯棒在管道中的燃烧特性。聚甲基丙烯酸甲酯棒在管道中燃烧，作为电缆火灾的替代品。模拟地下空间电缆火灾，测量了PMMA棒的燃烧特性、火焰传播速度和燃烧烟气。结果表明：1）在无气流条件下，直径为10 mm的棒不能维持燃烧; 2）当气流速度大于0.5 m/s时，燃烧变得强烈; 3）当棒支撑在管道顶部附近时，火焰传播速度加快，但在另一种条件下，速度没有明显增加.利用激光片流显示技术制作了一种新型的拱形支护巷道模型，并对其内部流动进行了测量。在支护附近有大量的涡流，但有无支护巷道的主流没有本质的区别。并对掘进工作面附近存在障碍物的模型进行了实测.地下空间火灾计算机模拟程序的开发除程序本身的开发外，还发现了几个重要的条件，即计算边界到通风管道的距离应较大，网格尺寸应较小，否则精度无法保证。

The results of experiments executed in this year are as follows.1. Characteristics of combustion of a PMMA rod in a duct.Rods of PMMA were burned in a duct as a substitute for a cable fire. The burning characteristics, the spreading speed of the flame and the fume of the combustion, of the PMMA rods were measured for the simulation of a cable fire in subsurface space. Then, 1) a combustion of 10 mm diameter rod could not be maintained under the condition of no airflow, 2) the combustion became intense when the air speed was more than 0.5 m/s, 3) the spreading speed of the flame became faster when the rod was supported near the roof of the duct although there were no apparent increase of the speed in another condition.2. Visualization of flow using laser light sheetA new roadway model with arch supports was made and the flow inside was measured. There were a lots of eddy near the supports, however, there was no essential difference in the main flow in the roadway between the models with and without supports. A model with some obstruct near the heading face was also measured.3. Development of a computer program to simulate a fire in subsurface spaceThere found several important conditions in addition to the development of the program itself, that is, the distance between boundary of the calculation and the ventilation duct should be large and the size of grid should be small or the accuracy can not be assured.