A fluorescent particle for PIV in gas phase flows

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL Experiments in Fluids Pub Date : 2024-10-14 DOI:10.1007/s00348-024-03889-8

Mizuki Okada, Agastya Parikh, Jorge Pinho, Christian Kähler, Sergio Lavagnoli

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Abstract

This paper presents the development of fluorescent tracer particles for use in gas flows as a countermeasure for undesired strong light reflections on surfaces of channel walls or obstacles and as a label for the discrimination of multi-constituent flows. The employment of fluorescent dye-doped tracer particles with a wavelength-specific optical filter enables the separation of the Stokes-shifted particle light emission from reflections on surfaces and Mie scattering from non-fluorescing particles. The fluorescent particles were made of Pyrromethene 567 (P567) and Di-Ethyl-Hexyl-Sebacate (DEHS), and the addition of P567 was not found to alter the characteristics of the particles generated. Investigations in a low-speed wind tunnel revealed that the intensity of fluorescent emission is proportional to the dye concentration at least up to \(2.0\,\hbox {g l}^{-1}\). The efficacy of reflection removal was investigated in a setup with a metal turbine blade placed in the flow and a laser sheet oriented to impinge the blade surface. With the installation of an appropriate optical filter, undesired light reflections were successfully removed, and reasonable vector calculations were enabled in proximity to the reflective blade surfaces. Finally, the performance of the modified DEHS was compared to conventional DEHS with the measurement of a canonical turbulent boundary layer (TBL). The flow was globally seeded with conventional DEHS and the TBL was locally seeded with fluorescing DEHS; simultaneous imaging with a notch filter confirmed that the flow is accurately tracked by the modified DEHS without additional bias. Furthermore, this indicated the possibility of using the newly developed particles to segregate portions of a flow with multiple constituents.

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用于气相流 PIV 的荧光颗粒

本文介绍了用于气体流动的荧光示踪粒子的开发情况，这种粒子既可作为通道壁表面或障碍物上不受欢迎的强光反射的对策，也可作为识别多成分流动的标签。使用掺杂荧光染料的示踪粒子和特定波长的光学滤光片，可以将斯托克斯位移粒子的光发射与表面反射和非荧光粒子的米氏散射分离开来。荧光颗粒由吡咯并噻吩 567（P567）和二乙基己基蔗糖酸酯（DEHS）制成，添加 P567 不会改变所生成颗粒的特性。在低速风洞中进行的研究表明，荧光发射强度与染料浓度成正比，至少达到（2.0\,\hbox {g l}^{-1}\）。我们在一个装置中研究了去除反射的效果，该装置是将一个金属涡轮叶片置于气流中，激光片的方向是撞击叶片表面。通过安装适当的光学滤波器，成功地消除了不必要的光反射，并在靠近反射叶片表面的地方进行了合理的矢量计算。最后，通过测量典型湍流边界层（TBL），将改进型 DEHS 的性能与传统 DEHS 进行了比较。使用传统 DEHS 对流动进行全局播种，使用荧光 DEHS 对 TBL 进行局部播种；使用陷波滤波器进行同步成像证实，改进型 DEHS 可以准确跟踪流动，而不会产生额外的偏差。此外，这还表明可以使用新开发的颗粒来隔离含有多种成分的水流部分。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Experiments in Fluids 工程技术-工程：机械

CiteScore

5.10

自引率

12.50%

发文量

157

审稿时长

3.8 months

期刊介绍： Experiments in Fluids examines the advancement, extension, and improvement of new techniques of flow measurement. The journal also publishes contributions that employ existing experimental techniques to gain an understanding of the underlying flow physics in the areas of turbulence, aerodynamics, hydrodynamics, convective heat transfer, combustion, turbomachinery, multi-phase flows, and chemical, biological and geological flows. In addition, readers will find papers that report on investigations combining experimental and analytical/numerical approaches.