基于气流均匀分配的大型袋式除尘器布风风道的几何特性

Geometric Characteristic for Duct of Airflow Distribution of Large-scale Bag Filter Based on Airflow Uniform Distribution

以大型袋式除尘器为对象,研究其布风风道的气流分配不均匀性,以解决由此导致的除尘效率低、压降偏高及运行成本上升等问题;分析了表征布风风道内流体流动特性的不可压缩恒定流能量方程的相关参数,重点研究了布风风道流动摩擦阻力系数λ、局部阻力系数ζ的影响因素及量化方法,确定了风道的几何结构;采用数值模拟方法分析了布风风道内气流分配均匀性.结果表明,该风道内气体流动处于紊流第IV区,可用阿里特苏里公式确定风道摩擦阻力系数λ;当布风风道结构参数ψ一定时,局部阻力系数ζ与风速比C相关,C<2.155时ζ的变化呈指数规律增大,C>2.155时ζ的变化区间为1.51～1.57,逐渐趋于稳定;改进前后布风风道内流体流动分配的不均匀系数U分别为0.70和0.93,表明改进后布风风道内流体流动分配均匀性显著提高.

Aiming at large-scale bag filter, this paper studied the airflow distribution non-uniformity of its airflow distribution duct, in order to solve the problems such as low collection efficiency, high pressure drop and high operation cost and so on caused by that. Incompressible steady flow energy equation, used to characterize fluid flow properties of duct of airflow distribution, of which the relative parameters were analyzed. Especially, influencing factors of frictional resistance coefficient λ, local resistance coefficient ζ and their quantitative method were mainly studied, and ultimately determine the geometry of the duct, then, the duct airflow distribution uniformity was analyzed by numerical simulation method. The results showed that the duct airflow patterns located in turbulent IV area, so frictional resistance coefficient λ was determined by Альтщуль formula. When the structure parameters ψ of the duct was determined, local resistance coefficient ζ was only related to speed ratio C, When C〈2.155, the change ζ exponentially increased, when C〉2.155, the ζ value change interval is 1.51～1.57, gradually stabilized. By comparing the flow distribution non-uniformity coefficient U of the duct（0.70 before improvement and 0.93 after improvement）, the flow distribution uniformity was proved to get improved significantly.