Characterisation and airborne deployment of a new counterflow virtual impactor inlet
Characterisation and airborne deployment of a new counterflow virtual impactor inlet
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DOI：
10.5194/amt-5-1259-2012
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发表时间：
2012-06
影响因子：
3.8
通讯作者：
Taylor J. Shingler;S. Dey;A. Sorooshian;F. Brechtel;Zhen Wang;A. Metcalf;M. Coggon;J. Mülmenstädt-J.-Mülmen
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文献类型：
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作者：
Taylor J. Shingler;S. Dey;A. Sorooshian;F. Brechtel;Zhen Wang;A. Metcalf;M. Coggon;J. Mülmenstädt-J.-Mülmen
抽象的。在 2011 年东太平洋排放气溶胶云实验 (E-PEACE) 期间，介绍了一种新型逆流虚拟冲击器 (CVI) 入口，详细介绍了其设计、实验室表征测试以及在飞机上的部署。 CVI 入口解决了先前设计中的三个关键问题；特别是，进样口在以下情况下运行： (i) 有机污染可忽略不计； (ii) 流向下游仪器的显着样品流速（~15 l min−1），减少了稀释的需要； (iii) 探头内部易于清洁。风洞实验表征了采样液滴的切割尺寸以及探针各个部分中与颗粒尺寸相关的传输效率。对于一系列逆流速率和空气速度，测量的切割尺寸在 8.7–13.1 μm 之间。切割尺寸测量值与空气动力阻力理论预测之间的平均百分比误差为 1.7%。 2011 年 7 月和 8 月，CVI 在 E-PEACE 期间部署在跨学科远程驾驶飞机研究中心 (CIRPAS) Twin Otter 上，进行了 30 次飞行，以研究加利福尼亚州中部海岸附近的气溶胶-云-辐射相互作用。报告的结果用于评估入口的性能，包括比较 CVI 下游的颗粒数浓度和由两个独立飞机探测器测量的云滴数浓度。 CVI 下游的测量结果也通过一次具有代表性的飞行案例进行了检查，该飞行与船上发射的烟雾相协调，该烟雾被双水獭在云中拦截。
Abstract. A new counterflow virtual impactor (CVI) inlet is introduced with details of its design, laboratory characterisation tests and deployment on an aircraft during the 2011 Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE). The CVI inlet addresses three key issues in previous designs; in particular, the inlet operates with: (i) negligible organic contamination; (ii) a significant sample flow rate to downstream instruments (∼15 l min−1) that reduces the need for dilution; and (iii) a high level of accessibility to the probe interior for cleaning. Wind tunnel experiments characterised the cut size of sampled droplets and the particle size-dependent transmission efficiency in various parts of the probe. For a range of counter-flow rates and air velocities, the measured cut size was between 8.7–13.1 μm. The mean percentage error between cut size measurements and predictions from aerodynamic drag theory is 1.7%. The CVI was deployed on the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter for thirty flights during E-PEACE to study aerosol-cloud-radiation interactions off the central coast of California in July and August 2011. Results are reported to assess the performance of the inlet including comparisons of particle number concentration downstream of the CVI and cloud drop number concentration measured by two independent aircraft probes. Measurements downstream of the CVI are also examined from one representative case flight coordinated with shipboard-emitted smoke that was intercepted in cloud by the Twin Otter.