Abstract Particle and vapor measurements typically include sampling tubing causing sampling losses therein. Correcting measured concentrations from the sampling losses using the calculated penetration efficiencies of straight tubes is a satisfactory approximation if sub-micrometer particles are of interest. However, in addition to inertial impaction of larger particles, bends in the tubing can cause a significant increase in diffusional losses of particles smaller than 5 nm or of condensing vapor, such as sulfuric acid. Here, the effects of 90° bends with various curvatures (dimensionless curvatures of 1.3 − 67 ) on the diffusional losses in a wide range of Reynolds ( 25 − 10000 ) and Schmidt ( 0.48 − 1400 ) numbers were simulated using computational fluid dynamics. The results were parametrized to output the functions for the penetration efficiencies of a bend.

中文翻译：

---

CFD 模拟纳米团簇大小的粒子的扩散损失和圆管 90° 弯曲中的冷凝蒸汽

摘要 粒子和蒸汽测量通常包括采样管，在其中造成采样损失。如果对亚微米颗粒感兴趣，则使用计算出的直管穿透效率从采样损失中校正测量浓度是令人满意的近似值。然而，除了较大颗粒的惯性撞击之外，管道中的弯曲会导致小于 5 nm 的颗粒或冷凝蒸汽（例如硫酸）的扩散损失显着增加。在这里，使用计算流体动力学模拟了具有各种曲率（1.3 - 67 的无量纲曲率）的 90°弯曲对各种雷诺 (25 - 10000) 和施密特 (0.48 - 1400) 数的扩散损失的影响。