温度场内可吸入颗粒物运动特性的实验研究

对温度场内可吸入颗粒物的运动特性进行了实验研究,使用PDA测量了场内可吸入颗粒物的速度和浓度分布等参数,研究了实验段入口速度和温度等操作参数对温度场内颗粒相运动特性的影响.结果表明,在近冷壁区边界层内,PM2.5的轴向速度和脉动速度变化很大,颗粒因热泳力及扩散作用会向冷壁面运动并产生沉积.在实验研究的基础上,提出了计算温度场内PM2.5沉积效率的经验公式.

INVESTIGATION ON DYNAMIC CHARACTERISTICS OF INHALED PARTICLES IN TEMPERATURE FIELD

Experiments have been carried out to study the dynamic characteristics of inhaled particles in a rectangle channel with temperature gradient.PDA was used to measure the distributions of velocity and concentration of the fine particles in the temperature field.During the experiments,the influence of the inlet temperature and inlet flow rate on the motion of the particles in the channel was investigated.The experimental results show that in the boundary layer near the cooled wall,the axial average velocity,the fluctuation velocity,the turbulence intensity and the concentration of the fine particles change greatly.PM2.5 can move to the cooled wall under the action of thermophoresis and then deposit to the cooled wall.Based on the experimental results,an empirical correlation for the calculation of deposition efficiency of PM2.5 caused by thermophoresis has been presented.