2D Phase Doppler Particle Analyzer (PDPA) Laser Upgrade

多相流，特别是喷雾，已被认为是许多技术和自然系统不可或缺的重要现象。其中包括农用喷雾剂、吸入给药系统、热喷涂涂层等。在这种系统中，表征液滴大小和速度分布最有效的仪器之一是双组分相位多普勒粒子分析仪（PDPA）。相位多普勒法是基于光散射干涉测量的原理。测量是在一个小的，非侵入式的光学探头体积定义的两个激光束的交集。两束光束的相交在探针体积内产生条纹图案。当液滴（或粒子）通过探针体积时，它会散射光束中的光并投射出条纹图案。

Multiphase flows and specifically sprays have been acknowledged as an important phenomenon integral to many technological and natural systems. Among them are agricultural sprays, inhaled drug delivery systems, thermal spray coating, etc. One of the most effective instruments available for characterizing the droplet size and velocity distribution in such systems is a two-component Phase Doppler Particle Analyzer (PDPA). The Phase Doppler Method is based upon the principles of light scattering interferometry. Measurements are made at a small, non-intrusive optical probe volume defined by the intersection of two laser beams. The intersection of the two beams creates a fringe pattern within the probe volume. As a droplet (or particle) passes through the probe volume, it scatters light from the beams and projects the fringe pattern. The application of the proposed equipment is for the research on i) the development of functional and environmental protective coatings produced by the emerging suspension thermal spray processes, ii) advancement of the liquid accelerated cold spray (LACS) deposition system, iii) design the next-generation spray nozzles for more efficient injection and transportation of suspensions and complex fluids of nanoparticles in high speed flows, and iv) study of the COVID-19 transmission via respiratory droplets. By measuring the particle velocity and size distributions, we will develop correlations relating these parameters to the spray nozzle design, the inlet flow conditions as well as risk of transmission of the COVID-19 virus through respiratory droplets. Such correlations will not only be used by industry and health sectors, but will allow us to validate our numerical results and better understand the relationship between various governing parameters and the spray characteristics. The results of this study will facilitate manufacturing of key aerospace, automotive, and biomedical components, all of which are important to the Canadian economy.