通风管道内温湿度对颗粒沉积的影响

于矩形断面0．3m×0．2m、长度3m的通风管道中，对完全发展湍流中的颗粒沉积进行了模拟计算。由于空调通风管道内空气温、湿度有所变化，因此综合考虑了热泳力及湿度对颗粒沉积的影响，采用拉格朗日法随机轨道模型进行了3000个颗粒沉积的模拟研究。在粒径范围0．01～50μm、管道风速5m／s的条件下，得到了无因次沉积速率随无因次松弛时间变化曲线并与前人的研究结果进行了比较，结果表明曲线呈现“V”形分布，模拟结果与前人研究结果基本一致。针对粒径19m的颗粒，调查了温度及湿度对颗粒沉积的影响，结果表明由气流与管壁的温差产生的热泳力加速了颗粒沉积，并随温差的增加而呈提高趋势；随着空气相对湿度的提高，颗粒沉积速率也相应增加，

Effects of Air Temperature and Humidity on Particle Deposition in a Ventilation Duct

Particle deposition in a fully developed turbulent flow of ventilation duct with a rectangular cross section of 0.3 m×0.2 m and 3 m in length was investigated. The effects of thermophoretic force and air humidity were also considered. Trajectories of 3 000 particles were tracked on the basis of the random walk model from Lagrangian approach. The profile of dimensionless deposition velocity with relaxation time was achieved and the comparison with the previous studies was made with particle size range of 0.01-50μm and air flow velocity of 5 m/s. It is found that the trend of dimensionless deposition velocity is in agreement with the previous studies and the profile of dimensionless deposition velocity showed a V-shaped curve. The effects of temperature and air humidity were also investigated with particle size of 1 μm. Thermophoretic force caused by temperature gradient between air flow and wall surface accelerated particle deposition. Meanwhile, it is also found that the deposition velocity increases with the increase of air relative humidity.