基于散射结构的脉冲流场与清灰压力动态特性分析

针对传统脉冲清灰中存在清灰不均匀的问题，应用上部开口散射器改善滤筒内部流场特性，从而改善清灰效果。通过数值模拟方法研究不同工况下滤筒内部脉冲流场及清灰压力的动态变化规律，探究清灰压力峰值形成机理。结果表明:脉冲喷吹气流以压力波的方式进入滤筒并向侧壁传递，而侧壁处气流径向速度与相同测点的清灰压力随时间等比例同步变化，两者存在直接关联。由于散射器对脉冲喷吹气流的分流和导流作用，相对无散射器而言，滤筒上部径向速度提高，清灰压力相应增大，其峰值由484 Pa增至744 Pa，增加了53.7%；滤筒中、下部，散射器的存在使脉冲喷吹流量和轴向速度减小，降低了脉冲气流对滤筒内部气流的压缩作用，滤筒中下部压力降低，滤筒下部清灰压力峰值由2175 Pa减小至1468 Pa，减小了32.5%。因此增设散射器可以在满足清灰要求的同时明显提高脉冲清灰的均匀性。

DYNAMIC CHARACTERISTICS OF FLOW FIELD AND CLEANING PRESSURE BASED ON SCATTERING STRUCTURE

In order to solve the problem of non-uniformity in the traditional pulse cleaning, the upper open scatter had been proposed to improve the internal flow field characteristics of the filter cartridge, so as to improve the cleaning efficiency. By numerical simulation method, the dynamic changes of pulse flow field and the dust cleaning pressure in the filter cartridge under different conditions were investigated, and the formation mechanism of the peak pressure of ash cleaning was explored. The results showed that the pulse-jet flow entered the filter cartridge in the form of pressure wave and transferred to the sidewall, and the pressure and radial velocity of the sidewall changed synchronously with time, and there was a direct connection between them. As a result of the diverting and guiding effect of the scatter on the jet flow, compared with no scatter case, the radial velocity of the upper part of the filter cartridge increased, thus dust cleaning pressure increased correspondingly, which the dust cleaning pressure increased from 484 Pa to 744 Pa, by 53.7%. On the contrary, the flow rate and axial velocity of the impulse injection in the middle and lower part of the filter cartridge would be reduced, the compression effect of the impulse airflow on the gas inside the filter cartridge would be reduced as well. The pressure in the middle and lower parts would be reduced respectively, and the pressure peak in the lower part decreased from 2175 Pa to 1468 Pa, by 32.5%. Therefore, adding a scatterer could obviously improve the uniformity of pulse ash cleaning and meet the requirements of ash cleaning.