Stiti Mehdi, Garcia Sebastien, Lempereur Christine, Doublet Pierre, Kristensson Elias, Berrocal Edouard
Opt Lett. 2023 Aug 1;48(15):4065-4068. doi: 10.1364/OL.495793.
Previous research has shown that the polarization ratio technique allows the characterization of the surface mean diameter, D, of droplets forming dilute sprays. However, its application to optically dense sprays has posed significant challenges due to the presence of multiple light scattering. Additionally, errors in measurement can arise from the angular dependence of the signal. In this Letter, we present a novel, to the best of our knowledge, method that addresses these challenges. Our approach combines the use of a telecentric objective with structured laser illumination, to both optimize light detection and suppress the unwanted intensity from multiple scattering. This approach enables the utilization of the polarization ratio technique for measuring the droplet size of challenging atomizing sprays. The method offers a promising solution for accurate and comprehensive spray characterization. It is applied, here, to a hollow-cone water spray running at 30, 50, and 70 bar injection pressure, reaching an optical depth up to three.
先前的研究表明，偏振比技术能够表征形成稀喷雾的液滴的表面平均直径D。然而，由于存在多次光散射，将其应用于光学密集喷雾面临着重大挑战。此外，测量误差可能源于信号的角度依赖性。在本信函中，据我们所知，我们提出了一种新颖的方法来应对这些挑战。我们的方法将远心物镜与结构化激光照明相结合，以优化光检测并抑制多次散射产生的 unwanted 强度。这种方法能够利用偏振比技术测量具有挑战性的雾化喷雾的液滴尺寸。该方法为准确和全面的喷雾表征提供了一个有前景的解决方案。在此，它被应用于在30、50和70巴喷射压力下运行的空心锥水喷雾，光学深度达到3。 （注：原文中“unwanted”未翻译完整，可能是“不需要的”之类意思，因不明确准确含义，按原文呈现）
