基于图像识别的微细粒子静电捕集效率评价方法

Evaluation Method of Fine Particle Electrostatic Collection Efficiency Based on Image Identification

通过采集并分析电除尘器内部流场和粒子分布动态和静态图像的方法,对微细粒子捕集效率进行评价。实验电除尘器箱体采用有机玻璃材质,放电极为芒刺型,测试粒子源为人工烟气,烟气入口流速为0.4 m/s。实验中对放电极分别施加直流和脉冲高电压,采集相应流场变化的图像和电除尘器入风口与出风口粒子分布的图像进行处理和分析。实验结果表明:提出的动静态图像处理方法能够实时、有效地实现微细粒子观测和荷电状态评价。直流供电下,流场在电压升至–8 kV开始呈现漩涡变化;而施加脉冲高压时,峰值电压达到–30 kV时产生漩涡。电压在–22 kV以下时,直流供电粒子捕集效率较高;电压超过–22 kV后,脉冲供电粒子捕集效率高于直流,最终捕集效率可达91.23%。

Fine particle collection efficiency is evaluated by obtaining and analyzing dynamic flow field inside electrostatic precipitator（ESP） and dynamic/static images of particles distribution. The side-wall of electrostatic precipitator consists of acrylic material, and the discharge electrodes are spike-type. The man-made smoke is considered to be the particle source for testing, and the flow velocity of the inlet is 0.4 m/s. In the experiment, the discharge electrode is energized with DC and short pulsed high voltage, respectively. Then, the images which contain the flow field changing and smoke particles distribution of inlet and outlet of ESP are processed and analyzed. The experimental results indicate that the method of processing dynamic and static images can be used to observe fine particles and evaluate particles charging status timely and effectively. Energized with negative DC high voltage, the vortexes of the flow field begin to appear when the voltage value rises to –8 kV. While energized with negative short impulses high voltage, the vortexes appear when the peak voltage value rises to –30 kV. The particles collection efficiency with DC energization is higher when the voltage value is lower than –22 kV. While the voltage value exceeds –22 kV, the particles collection efficiency energized by impulses high voltage is higher than that by DC energization, and the final collection efficiency can be up to 91.23%.