In-situ measurement of size distribution and concentration in dilute particle flow with digital holographic probe

Gas-solid two-phase flows are common in both industrial processes and natural phenomena, and accurately detecting particle properties within these flows is crucial for process optimization and control. However, existing particle detection techniques often struggle to provide in-situ, real-time, and multi-parameter measurements in complex flow environments. To address this challenge, a new digital holographic probe, designed for compactness and 3D measurement capability, is developed in this work. The delicate structure of the probe head makes it suitable for use in pneumatically conveyed particle flows within pipes, with a measurement volume of 435.6 mm 3 . The measurement performance of the holographic probe has been verified on a pipeline pneumatic transport test platform under various particle size and concentration conditions. Using 3D holographic imaging, the spatial distribution of particles within the measurement volume was analyzed. Experimental results show that the relative deviation of the mass median diameter is less than 3 %, while the relative deviation of the average mass concentration is below 12 %, compared to reference results.