一种改进的低密度薄壁中空微球预混料均匀性及密度表征方法

基于多级粉体堆积理论，建立了低密度薄壁中空微球预混料的堆积模型和理论密度计算方法；基于微球混合物的图像色彩亮度和混合均匀性存在一定映射关系，使用图像二值法进行图像采集处理，并引入综合分散度表征混合均匀度；设计了低密度薄壁中空微球预混料的密度及混合均匀性测量系统，通过PLC可实现压力和位移的可控精确测量。使用本测量系统对微球预混料进行了10组实验的密度值测定，结果表明：测得的预混料的平均密度为0.431 2 g/cm³，预混料的理论密度为0.428 2 g/cm³；密度测定的相对标准差为0.25%，与手工称量瓶法相比，本测量系统的密度重复测试精度提高了1.12倍，且平均密度更接近理论密度。测定了不同混合程度的3种预混料的混合均匀性，结果表明：随着预混料由粗混到精混，其对应的综合分散度逐渐增大并接近理想样品，采用本文算法得到的预混料的综合分散度量化数值能够反映预混料的混合均匀度。

Improved uniformity and density characterization of a low-density thin-walled hollow microsphere premix

By means of multi-stage powder accumulation theory, an accumulation model and a method for calculating the theoretical density of a low-density thin-walled hollow microsphere premix have been established. Based on the mapping relationship between the color brightness and the mixing uniformity of the microsphere mixture, image acquisition and processing were carried out using the image binary method, and a comprehensive dispersion was introduced to characterize the mixing uniformity. A system for measuring the density and mixing uniformity of a low-density thin-walled hollow microsphere premix was designed. The controllable and accurate measurement of pressure and displacement can be realized by PLC. The density values of 10 groups of tests were measured, and the results showed that the average density of the premix was 0.431 2 g/cm³, and the theoretical density of the premix was 0.428 2 g/cm³. The relative standard deviation of the density measurements was 0.25%. Compared with the manual weighing bottle method, the repetition accuracy of the measurement system was improved by a factor of 1.12, and the average density is closer to the theoretical density. The mixing uniformities of the three premixes with different mixing degrees were measured. The results showed that the comprehensive dispersion gradually increased and approached the ideal value as the premix was varied from coarse mixing to fine mixing. The quantitative value of the comprehensive dispersion of the premix obtained using this algorithm can reflect the mixing uniformity of the premix.