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对流作用在火灾诱导的烟气运动中占主导地位。为了更好地研究火灾诱导的烟气运动,该文构造了一种新的4阶精度的有限差分格式,用以离散火灾烟气运动的控制方程——低M ach数可压缩N av ier-S tokes方程的对流项。将此格式加入到美国国家标准技术局开发的火灾模拟软件F ireD ynam ics S im u lator(FDS)中,对典型的油池火灾和单室火灾的问题进行了数值模拟。将速度和温度分布的计算结果与实验结果和二阶精度的FDS程序计算结果相比较,结果表明该文提出的格式在较少的网格下得到了比二阶精度格式更接近于实验值的结果。这说明在火灾模拟中,相对于二阶精度的格式来说,高精度格式是一种更好的选择。
Convection plays a dominant role in fire-induced smoke movement. In order to study the fire-induced flue gas movement better, a new fourth-order finite-difference finite difference scheme is constructed to control the flue gas movement in fire with a low Mach number compressible N av ier- Convection term of S tokes equation. This format was added to a fire simulation software developed by the U.S. National Institute of Standards and Technology (FDS) to simulate typical tank fire and single-chamber fire problems. Comparing the results of velocity and temperature distributions with those of experimental and second-order FDS programs, the results show that the proposed scheme achieves results that are closer to the experimental values than the second-order precision scheme with fewer meshes . This shows that in the fire simulation, high-precision format is a better choice than the second-order precision format.