Monitoring the dust cloud dispersion process inside testing equipment like the MIKE3 minimum ignition energy device is useful for assessing the ignitability characteristics of different dust materials. However, it is difficult to comprehensively capture the relevant micro-scale particle properties and macro-scale flow behavior of a dust cloud dispersion using a single measurement method. Thus, the objective of this work is to combine two complementary laser diagnostic techniques to obtain quantitative particle and flow properties from dust clouds in the MIKE3 glass tube. For this experiment, thirty repeated runs for each method were conducted using small (15-mg) aluminum powder samples. No ignition electrodes are included in the test geometry to establish a baseline flow configuration for the glass tube, although measurements are still made at the characteristic time delay and location of ignition tests. The first technique, digital in-line holography (DIH) is used for three-dimensional micro-scale particle diagnostics, yielding particle number ($n$ = 78 ± 20), size ($\bar{D}$ = 18.9 ± 0.6 µm), and three-component velocity (${\bar{v}}_x$ = 0.05 ± 0.05 m/s, ${\bar{v}}_y$ = 0.60 ± 0.09 m/s, ${\bar{v}}_z$ = − 0.07 ± 0.16 m/s) measurements. The second laser diagnostic technique, particle image velocimetry (PIV), is used for macro-scale flow diagnostics, yielding two-dimensional flow velocity and vorticity vector field measurements. Particle sizes are observed to follow a lognormal distribution (μ = 2.89, σ = 0.31), and a discrepancy between in-situ and ex-situ sizing results is identified for particle sizes larger than ~55 µm. Two-dimensional particle velocities follow a Weibull distribution (θ = 0.86, β = 2.12), and reasonable agreement is found between the DIH and PIV velocity measurements.

监测 MIKE3 最小点火能量装置等测试设备内部的粉尘云扩散过程，有助于评估不同粉尘材料的可燃性特性。然而，使用单一的测量方法难以全面捕捉尘埃云分散体的相关微观尺度颗粒特性和宏观尺度流动行为。因此，这项工作的目的是结合两种互补的激光诊断技术，从 MIKE3 玻璃管中的尘埃云中获得定量的粒子和流动特性。在本实验中，每种方法使用小 (15-mg) 铝粉样品重复运行 30 次。测试几何中不包括点火电极来建立基线玻璃管的流动配置，尽管仍然在特征时间延迟和点火测试的位置进行测量。第一种技术，数字在线全息（DIH）用于三维微尺度粒子诊断，产生粒子数（$n$= 78 ± 20), 尺寸 ($\bar{D}$= 18.9 ± 0.6 µm）和三分量速度（${\bar{v}}_X$= 0.05 ± 0.05 米/秒，${\bar{v}}_{\mathrm{是的}}$= 0.60 ± 0.09 米/秒，${\bar{v}}_z$= − 0.07 ± 0.16 m/s) 测量值。第二种激光诊断技术，粒子图像测速 (PIV)，用于宏观尺度流动诊断，产生二维流速和涡量矢量场测量。观察到粒度遵循对数正态分布(μ = 2.89, σ = 0.31)，并且对于大于 ~55 µm 的粒度，确定了原位和非原位上浆结果之间的差异。二维粒子速度遵循 Weibull 分布 (θ = 0.86, β = 2.12)，并且在 DIH 和 PIV 速度测量值之间发现了合理的一致性。