【摘要】 振打清灰是保证静电除尘器正常运行的一个重要环节。为确定振打加速度,基于Penney和Klingler理论,认为带电粉尘层对收尘极板的附着力主要是外电场力和附加电场力共同作用的结果。附加电场是由于电晕电流通过沉积在收尘极板上的粉尘层产生电荷积累而形成的。应用静电学理论导出粉尘层内电场分布与带电粉尘层厚度的平方成正比。通过建立荷电粉尘层对收尘极板附着力的微分方程,由牛顿第二定律得出振打加速度的理论计算式。研究结果表明,振打加速度是电晕电流面密度和粉尘比电阻乘积ρ×J的函数,且与粉尘粒径成反比。参考已发表的实验数据和理论结果发现,在外加电压保持不变的情况下,电晕电流面密度和粉尘比电阻的乘积ρ×J=常数,此时,振打加速度与ρ×J无关。从这一新观点出发,根据Oglesby提供的粉尘层击穿前的电晕电流和粉尘比电阻的相关曲线,得出临界振打加速度计算式。由此计算式给出了一种确定临界振打加速度的简易图解法。更多还原

【Abstract】 The present paper aims to report on the additional field distribution by the electrostatics developed by the author with the dust collector. Our research on the additional field distribution indicates that the electric field is proportional to the square of the dust layer thickness. As we know, it is very important to determine the rapping acceleration for maintaining the performance of electrostatic precipitator (ESP) at desirable operational condition. For this purpose, there are two main forces acting upon the charged dust layer deposited on the collection electrode based on Penney and Klingler’s theory. One of the forces is produced by the electric field between the corona electrode and grounded collection electrode. The other is generated by an additional field that is built up by the accumulated charges in the dust layer since the corona current flows through this layer. Thus the differential equation can be established to obtain the adhesive force on the collection electrode. Therefore, a theoretical formula used to calculate the rapping acceleration is derived in accordance with the Newton’s second law. This result shows that the rapping acceleration performs the function of the product of the dust resistivity ρ and the corona current density J, and is inversely proportional to the particle diameter. If the voltage keeps unchangeable, the product of the dust resistivity and the current density, ρ×J, would be a constant according to the published experimental data and the theoretical values. In this case, the rapping acceleration is independent of ρ×J. From this new point of view, a critical rapping acceleration equation can be given based on the correlation curve of ρ and J presented by Oglesby. And, finally, following this equation, a simple graphical method has also been proposed in this paper to determine the critical rapping acceleration.更多还原