Three-Dimensional Numerical Simulation of Air Pollutant Dispersion in Street Canyons

The PHOENICS Computational Fluid Dynamics (CFD) software package has been used with a standard k- turbulence model to simulate the three-dimensional dispersion of air pollutants in an urban street canyon. In all cases, a vortex was formed within the street canyon, characterized by updrafts near the upwind buildings and down-drafts near the downwind buildings. Contours of pollutant concentrations over a transverse vertical plane at mid-canyon show pollutants circulating within the vortex, with higher concentrations at the leeward face than at the windward faces, and higher concentrations above downwind buildings than above upwind buildings. Longitudinal distributions of pollutant concentrations at leeward and windward faces are characterized by higher concentrations at mid-block and lower concentrations at the ends. These results agree qualitatively with previous wind tunnel findings such as those of Hoydysh and Dabberdt (1988) and Wedding et al. (1977). The results also suggest that the k- turbulence model is satisfactory for simulating the effect of turbulence on dispersion of pollutants in street canyons     

不同开口状况下多层建筑火灾烟气运动的数值模拟

建筑物发生火灾时,因火灾而伤亡者中大多数为烟害所致。高层建筑中由于存在“烟囱效应”的作用,烟气更容易向上迅速蔓延,而不同的开口状况将影响这种蔓延速度。本文阐述了多层建筑火灾烟气运动的数学模型及数值方法,应用PHOEN ICS3.5对多层建筑火灾产生的烟气运动进行了模拟,分析比较了不同开口状况下火灾烟气的运动状况;同时,初步论述了PHOEN ICS用在建筑火灾烟气运动的数值模拟上的优点和可行性,以及用它来模拟不同开口状况下多层建筑火灾烟气运动的实用性。     

罐区气体泄漏PHOENICS数值模拟研究

基于紊流模式理论,在考虑重力影响的基础上,建立储气罐区气体泄漏扩散数学模型,并采用计算流体力学软件PHOENICS(双曲性,抛物性或椭圆型数值求解综合编码)对该数学模型进行数值求解。在油气安全综合平台上,通过选用二氧化碳作为泄漏物,红外二氧化碳传感器采集来的实验数据与PHOENICS模拟数据进行比较,发现误差较小。同时表明,借用该软件模拟储气罐区气体泄漏的扩散问题是可行的。运用该法也能为气体泄漏、火灾方面的研究提供一条便利的捷径。研究结果还可以为液化气与毒气罐区气体泄漏事故应急处理提供参考依据,同时对罐区浓度探测点位置的安放也有重要指导意义。     

二段往复炉排焚烧炉炉拱的优化辅助设计

为实现二段往复炉排焚烧炉炉拱的优化设计 ,运用PHOENICS软件进行炉内流场的模拟 ,研究炉拱形状和尺寸对流场的影响。通过模拟发现 ,后拱后移可以避免压火现象 ,保证炉膛空间良好的火焰充满度 ,但存在最佳后移尺度 ,以同时保证喉口位置烟气湍流效果强烈 ,充分发挥炉膛后拱和前拱的辐射及对流传热的效果。根据炉内气流湍动情况以及风速的范围 ,确定在原设计基础上将后拱后移 0 5m为最佳炉膛尺寸