The scaling-up of spray drying processes is an important and challenging step in commercializing specialty products with an ensured quality because it mandates a comprehensive understanding of several steps in the process such as atomization, efficient solvent removal, and particle segregation. The formation of needed particle sizes and shapes is impossible without appropriate atomization through spray dryer nozzles. Hence, research is discussed that investigates the atomization mechanism for a pilot scale externally-mixed, two-fluid nozzle spray dryer by using time resolved particle-image velocimetry to study the behavior of droplets in the near-field of the nozzle tip. Important near-field dynamics of droplets emanating from the nozzle are described, and particle formation characteristics are discussed for several formulations which are widely used in the pharmaceutical industry. Spray angle, droplet breakup length, and droplet sizes and velocity distributions are characterized. Understanding these parameters assists the interpretation of particle formation and enables the modeling of the spray drying process.

扩大喷雾干燥工艺的规模是确保特种产品商业化并确保其质量的重要而富挑战性的一步，因为它要求全面理解工艺中的几个步骤，例如雾化，有效去除溶剂和颗粒分离。没有通过喷雾干燥器喷嘴的适当雾化，就不可能形成所需的粒径和形状。因此，讨论了研究，通过使用时间分辨粒子图像测速技术研究中试规模的外部混合双流体喷嘴喷雾干燥器的雾化机理，以研究喷嘴尖端近场中液滴的行为。描述了从喷嘴发出的液滴的重要近场动力学，讨论了在制药工业中广泛使用的几种配方的颗粒形成和颗粒形成特性。表征喷雾角度，液滴破裂长度以及液滴尺寸和速度分布。了解这些参数有助于解释颗粒的形成，并可以对喷雾干燥过程进行建模。