矩阵式静电传感器空间滤波法测量颗粒局部平均速度的准确度与其灵敏度分布特性密切相关。本文基于静电感应原理和点电荷思想,建立了矩阵式静电传感器三维静电场模型,应用有限元法分析了电极长度和张角以及电极轴向间隔对传感器灵敏度特性的影响,并建立了传感器灵敏度几何无量纲模型。仿真计算结果表明:灵敏度沿轴向分布的周期性均由传感器结构决定,并且在中心截面上呈局部分布特性。
The accuracy of local particle mean velocity measurement with spatial filtering method based on an electrostatic sensor matrix (ESM) is closely related to its sensitivity distribution char- acteristics. In this paper, the charge induced on the electrodes of the ESM with different geometric sizes from single particle having a unity charge is modelled mathematically, and the three-dimensional electrostatic field generated by the point charge in the sensing zone of the ESM is solved by using a finite element method. ~rther a dimensionless geometric calculation model for the sensitivity of the ESM is suggested. The results obtained demonstrate that the spatial sensitivity has a periodic distribution along the axial direction and that the sensitivity over the central cross-section is localized.