2D Phase Doppler Particle Analyzer (PDPA) Laser Upgrade

多相流和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。可用于表征此类系统中液滴大小和速度分布的最有效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原理的。测量是在由两束激光相交定义的小的、非侵入性的光学探头体积上进行的。两束光束的交点在探头体积内产生条纹图案。当液滴(或粒子)穿过探头体积时，它会散射光束中的光，并投射条纹图案。 拟议设备的应用将用于以下研究：i)开发新兴悬浮热喷涂工艺生产的功能性和环保型涂层；ii)液体加速冷喷涂沉积系统的进步；iii)设计新一代喷嘴，以便在高速流动中更高效地喷射和输送悬浮液和复杂的纳米流体；以及iv)研究新冠肺炎通过呼吸道液滴的传输。通过测量颗粒速度和粒度分布，我们将建立这些参数与喷嘴设计、入口流动条件以及通过呼吸道飞沫传播新冠肺炎病毒的风险之间的关联。这种关联性不仅将被工业和卫生部门使用，还将使我们能够验证我们的数值结果，并更好地理解各种控制参数与喷雾特性之间的关系。这项研究的结果将促进关键航空航天、汽车和生物医学部件的制造，所有这些对加拿大经济都很重要。

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.