Aerosol particle transport and deposition in vertical and horizontal turbulent duct flows
Aerosol particle transport and deposition in vertical and horizontal turbulent duct flows
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DOI：
10.1017/s0022112099007284
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发表时间：
2000-03
影响因子：
3.7
通讯作者：
Haifeng Zhang;G. Ahmadi
中科院分区：
文献类型：
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作者：
Haifeng Zhang;G. Ahmadi
研究了在不同重力方向作用下，气溶胶粒子在垂直和水平湍流管道中的输运和沉积。瞬时流体速度场是由Navier-Stokes方程通过伪谱方法直接数值模拟产生的。轨迹分析采用了包含Stokes阻力、布朗扩散、升力和重力的粒子运动方程。对8192个粒子路径的集合进行评估、编译和统计分析。结果表明，壁面共格结构在颗粒沉积过程中起着重要作用。在各种条件下的模拟沉积速度进行了比较与现有的实验数据和子层模型的预测。结果表明，剪切速度、密度比、剪切升力和流动方向影响颗粒沉积速率。垂直管道的计算结果表明，颗粒的沉积速度随重力方向的变化而变化，当剪切速度较小时，这种影响更为显著。对于水平管道，重力沉降增加了颗粒在下壁的沉积速率。
Aerosol particle transport and deposition in vertical and horizontal turbulent duct flows in the presence of different gravity directions are studied. The instantaneous fluid velocity field is generated by the direct numerical simulation of the Navier–Stokes equation via a pseudospectral method. A particle equation of motion including Stokes drag, Brownian diffusion, lift and gravitational forces is used for trajectory analysis. Ensembles of 8192 particle paths are evaluated, compiled, and statistically analysed. The results show that the wall coherent structure plays an important role in the particle deposition process. The simulated deposition velocities under various conditions are compared with the available experimental data and the sublayer model predictions. It is shown that the shear velocity, density ratio, the shear-induced lift force and the flow direction affect the particle deposition rate. The results for vertical ducts show that the particle deposition velocity varies with the direction of gravity, and the effect becomes more significant when the shear velocity is small. For horizontal ducts, the gravitational sedimentation increases the particle deposition rate on the lower wall.