1.1 本指南的目的是定义一种测试程序，用于应用激光衍射（LD）方法来估计平均液滴尺寸分布，该平均液滴大小分布表征了特定喷雾产生装置在特定气体共流条件下使用特定液体产生的液滴流量。预期范围仅限于具有高速共流的人工产生的喷雾。假设液滴的大小范围为1 µm至2000 直径为µm，并出现在体积小到几立方厘米或大到一立方米的喷雾中。 假设液滴尺寸在喷雾体积内分布不均匀。 1.2 本指南主要用于指导使用LD仪器测量喷嘴和雾化器的性能。 1.3 不均匀的喷雾需要在整个喷雾横截面上或通过几个弦进行测量，从而提供整个喷雾横截面积的代表性样本。多弦测量的目的是获得表征整个喷雾的单个液滴尺寸分布，而不是单个弦测量的值。 1.4 本指南的使用要求仪器不会干扰喷雾的产生，也不会显著影响或干扰气体和喷雾的共同流动。因此，这种技术被认为是非侵入性的。 1.5 根据光散射分布计算液滴尺寸分布是使用Mie散射理论或Fraunhofer衍射近似进行的。Mie理论的使用说明了通过液滴折射的光，并且对复折射率的实（折射）分量和虚（吸收）分量的知识有特定的要求。 Mie理论也依赖于液滴均匀性的假设。Fraunhofer衍射近似不考虑通过液滴折射的光，并且不需要折射率的知识。 1.6 仪器应包括数据处理能力，以根据实践将LD散射强度转换为液滴尺寸分布参数 E799 和试验方法 E1260 . 1.7 由LD仪器的发射器光学器件产生的准直光束可以看到和接近喷雾。 喷雾的形状和尺寸应包含在仪器制造商规定的LD系统光学器件的工作距离内。 1.8 LD光学器件的尺寸范围应适用于所研究的喷雾产生装置。例如，仪器报告的最小液滴尺寸等级的上限应不大于 1. / 4. 的大小 D V0.1 . 1.9 以国际单位制表示的数值应视为标准。本标准不包括其他计量单位。 1.10 本标准可能涉及危险材料、操作和设备。本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.11 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 本指南提供了一种使用LD仪器从近似通量敏感样品的气体共流喷雾中获得液滴尺寸分布的方法。 4. 5.2 在许多喷雾中，实验者应按大小说明液滴的空间分离。本指南提供了一种对液滴分布进行空间平均的方法。 5.3 所获得的结果本质上是统计的，并且是指整个喷雾的液滴尺寸分布的时间平均值。 5.4 本指南用于校准喷雾产生装置，以在预先指定的环境和共流条件下产生所需的液滴尺寸分布，或表征未知喷雾，同时最大限度地减少测量的不确定性。

1.1 The purpose of this guide is to define a test procedure for applying the laser diffraction (LD) method to estimate an average droplet size distribution that characterizes the flux of liquid droplets produced by a specified spray generation device under specified gas co-flow conditions using a specified liquid. The intended scope is limited to artificially generated sprays with high speed co-flow. The droplets are assumed to be in the size range of 1 µm to 2000 µm in diameter and occur in sprays that are contained within a volume as small as a few cubic centimetres or as large as a cubic metre. The droplet sizes are assumed to be distributed non-uniformly within the spray volume. 1.2 This guide is intended primarily to guide measurement of performance of nozzles and atomizers using LD instruments. 1.3 Non-uniform sprays require measurements across the entire spray cross section or through several chords providing a representative sample of the overall spray cross section. The aim of multiple-chord measurements is to obtain a single droplet size distribution that characterizes the whole spray rather than values from a single chordal measurement. 1.4 Use of this guide requires that the instrument does not interfere with spray production and does not significantly impinge upon or disturb the co-flow of gas and the spray. This technique is, therefore, considered non-intrusive. 1.5 The computation of droplet size distributions from the light-scattering distributions is done using Mie scattering theory or Fraunhofer diffraction approximation. The use of Mie theory accounts for light refracted through the droplet and there is a specific requirement for knowledge of both real (refractive) and imaginary (absorptive) components of the complex index of refraction. Mie theory also relies on an assumption of droplet homogeneity. The Fraunhofer diffraction approximation does not account for light refracted through the droplet and does not require knowledge of the index of refraction. 1.6 The instruments shall include data-processing capabilities to convert the LD scattering intensities into droplet size distribution parameters in accordance with Practice E799 and Test Method E1260 . 1.7 The spray is visible and accessible to the collimated beam produced by the transmitter optics of the LD instrument. The shape and size of the spray shall be contained within the working distance of the LD system optics as specified by the instrument manufacturer. 1.8 The size range of the LD optic should be appropriate to the spray generation device under study. For example, the upper bound of the smallest droplet size class reported by the instrument shall be not more than 1 / 4 the size of D V0.1 . 1.9 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.10 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.11 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This guide provides a means of using an LD instrument to obtain a droplet size distribution from a spray in gas co-flow that approximates a flux-sensitive sample. 4 5.2 In many sprays, the experimenter shall account for spatial segregation of droplets by size. This guide provides a means of spatial averaging the droplet distribution. 5.3 The results obtained will be statistical in nature and refer to the time average of droplet size distribution of the entire spray. 5.4 This guide is used to calibrate a spray generation device to produce a desired droplet size distribution under prespecified environmental and co-flow conditions or characterize an unknown spray while minimizing the uncertainty in the measurement.