Abstract Aircraft gas turbine engines produce ultrafine PM which has been linked to local-air-quality and environmental concerns. Regulatory sampling and measurement standards were recently introduced by ICAO to mitigate these emission of nonvolatile PM (nvPM). Currently, reported nvPM emissions can significantly under-represent engine exit concentrations due to particle loss. A System-Loss-Tool (SLT) has been proposed to correct for particle loss in the standard sampling and measurement system permitting an estimation of engine exit concentrations for airport environment inventories. Thermophoretic and bend particle loss mechanisms are predicted in the SLT using expressions derived from the literature, which are not in all cases empirically validated to conditions representative of aircraft nvPM exhaust sampling methodologies. In this study, thermophoretic (Tgas≤910 °C) and coiling-induced (≤3960°) particle loss were measured using sampling variables relevant to aerospace certification. Experiments were performed using laboratory generated solid particles (fractal graphite, cubical salt and spherical silica) bounding the upper and lower limits of aircraft soot morphology (i.e., particle effective density, mass-mobility exponent, primary-particle-size). These were aerodynamically classified using a Cambustion Aerodynamic-Aerosol-Classifier (AAC) at electrical-mobility diameters ranging from 30 to 140 nm. The AAC was shown to efficiently classify salt and silica particles, producing monomodal distributions ≥25 nm electrical-mobility GMD, whilst classifying fractal graphite >40 nm electrical-mobility GMD (calculated as da≥20 nm) albeit generally displaying larger GSD’s. Thermophoretic loss at ΔTgas of 0–880 K correlated well with the SLT for non-fractal particles with losses ≤39.2% measured, with higher depositions observed for graphite (4.1%) considered insignificant compared to overall measurement uncertainty. Coiling a 25 m sample line in compliance with ICAO standards induced negligible additional particle loss at flowrates relevant of aircraft exhaust sampling, in agreement with SLT-predicted bend losses. However, additional losses were witnessed at lower flowrates (≤13% at 30 nm), attributed to secondary flow diffusion loss induced by the coiling. Copyright © 2020 American Association for Aerosol Research

中文翻译：

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管制规定的飞机 nvPM 采样系统的热泳和弯曲纳米粒子损失的实验验证

摘要 飞机燃气涡轮发动机会产生超细颗粒物，这与当地空气质量和环境问题有关。国际民航组织最近引入了监管采样和测量标准，以减少这些非挥发性 PM (nvPM) 的排放。目前，由于颗粒损失，报告的 nvPM 排放量可能显着低于发动机出口浓度。已提议使用系统损失工具 (SLT) 来校正标准采样和测量系统中的粒子损失，从而可以估计机场环境清单的发动机出口浓度。热泳和弯曲粒子损失机制在 SLT 中使用源自文献的表达式进行预测，并非在所有情况下都对代表飞机 nvPM 排气采样方法的条件进行了实证验证。在这项研究中，使用与航空航天认证相关的采样变量测量热泳 (Tgas≤910 °C) 和卷曲诱导 (≤3960°) 粒子损失。实验是使用实验室产生的固体颗粒（分形石墨、立方盐和球形二氧化硅）进行的，这些固体颗粒限制了飞机烟尘形态的上限和下限（即颗粒有效密度、质量迁移率指数、初级颗粒尺寸）。这些是使用燃烧空气动力学气溶胶分类器 (AAC) 在 30 到 140 nm 范围内的电动移动直径下进行空气动力学分类的。AAC 被证明可以有效地对盐和二氧化硅颗粒进行分类，产生 ≥25 nm 电迁移率 GMD 的单峰分布，同时对 >40 nm 电迁移率 GMD（计算为 da≥20 nm）的分形石墨进行分类，尽管通常显示更大的 GSD。ΔTgas 为 0-880 K 时的热泳损失与非分形颗粒的 SLT 相关性良好，测量损失≤39.2%，与整体测量不确定性相比，观察到的石墨沉积物 (4.1%) 被认为无关紧要。根据国际民航组织标准盘绕 25 m 采样线在与飞机尾气采样相关的流速下引起的额外颗粒损失可以忽略不计，这与 SLT 预测的弯曲损失一致。然而，由于卷曲引起的二次流动扩散损失，在较低流速下（30 nm 时≤13%）会出现额外的损失。版权所有 © 2020 美国气溶胶研究协会 1%) 被认为与整体测量不确定度相比微不足道。根据国际民航组织标准盘绕 25 m 采样线在与飞机尾气采样相关的流速下引起的额外颗粒损失可以忽略不计，这与 SLT 预测的弯曲损失一致。然而，由于卷曲引起的二次流动扩散损失，在较低流速下（30 nm 时≤13%）会出现额外的损失。版权所有 © 2020 美国气溶胶研究协会 1%) 被认为与整体测量不确定度相比微不足道。根据国际民航组织标准盘绕 25 m 采样线在与飞机尾气采样相关的流速下引起的额外颗粒损失可以忽略不计，这与 SLT 预测的弯曲损失一致。然而，由于卷曲引起的二次流动扩散损失，在较低流速下（30 nm 时≤13%）会出现额外的损失。版权所有 © 2020 美国气溶胶研究协会