标准火灾测试房间温度场和速度场的大涡模拟

Large eddy simulation of temperature field and velocity field in standard fire test room

为探索单个房间内的火灾发展和烟气流动,采用大涡模拟(LES)方法,对大尺度涡进行直接数值模拟,对小尺度涡采用亚格子应力模型处理湍流,计算了标准火灾测试房间内的气流流动,得到了其温度场和速度场.模拟结果与采用二维多普勒激光测速仪和精细热电偶的试验数据相比较,除房间顶部外,模拟结果与试验数据吻合.模拟结果表明,房间内存在较大的温度梯度,温度场分层明显,密度差造成的浮力是气流运动的主要驱动力;重整化群(RNG)的亚格子应力模型适用于火灾的大涡模拟.

In order to probe into the fire development and smoke movement in a single room, the temperature field and velocity field in standard fire test room were simulated by the means of large eddy simulation （LES）. Large eddies were simulated directly, while small scale eddies were modeled by subgrid-scale turbulent model. The numerical results agreed well with the experimental data obtained two-dimensional laser Doppler velocity measurement and fine heat-couples with the exception of the region near the ceiling. Numerical results show that there are obviously stratified phenomena in both temperature and velocity field, and that the buoyancy caused by the density variation is the main driving force for the gas movement. Renormalization Group （RNG） Subgrid-Scale turbulent model gives good performance in fire simulation using LES technique.