• Acta Photonica Sinica
  • Vol. 51, Issue 3, 0311002 (2022)
Liang SHAN1, Feiyang SHI1, Bo HONG1, Daodang WANG2, Junzhe XIONG1, and Ming KONG2、*
Author Affiliations
  • 1Key Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province,College of Information Engineering,China Jiliang University,Hangzhou 310018,China
  • 2College of Metrology & Measurement Engineering,China Jiliang University,Hangzhou 310018,China
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    DOI: 10.3788/gzxb20225103.0311002 Cite this Article
    Liang SHAN, Feiyang SHI, Bo HONG, Daodang WANG, Junzhe XIONG, Ming KONG. Particle Field Simulation Imaging for Color-illuminated Particle Image Velocimetry[J]. Acta Photonica Sinica, 2022, 51(3): 0311002 Copy Citation Text show less

    Abstract

    Fluids are very common in nature and engineering. Research in engineering fields such as fluid mechanics and aerodynamics is closely related to fluid measurement. Measuring and analyzing the motion state of fluids is a key issue in the field of fluids. The particle image velocimetry method developed in the 1880s is a transient, multipoint, noncontact hydrodynamic velocimetry method. It can accurately measure the transient flow field in the plane without disturbing the fluid. This paper analyzes the imaging principle of tracer particles in the particle image velocimetry algorithm based on color illumination. According to the application environment in the actual flow field and the experimental conditions of the color particle image velocity measurement algorithm, a set of lighting systems consisting of a white light source and a filter with linearly changing wavelength is adopted to provide the particle field with color volume illumination of different depths and the same light intensity. Particles of different depths in the fluid that reflect the light of the corresponding wavelength are modeled as narrow band point light sources with different wavelengths. To obtain the accurate position of each particle imaging on the CCD, namely, the spectral distribution of the particle field, the camera pinhole imaging model is established to analyze and simulate the optical path of particle imaging. When the light reflected by particles passes through the pinhole model of the camera, imaging of particles on a CCD sensor can be achieved. First, the imaging diameter of particles is calculated by the Airy spot diameter and the real diameter of particles. Second, the normalized intensity matrix of the discrete image is obtained by the weight function of the particle intensity distribution because the strength distribution of particles should satisfy a two-dimensional Gaussian distribution. Finally, the particle's imaging diameter and intensity are combined to acquire the particle's point spread function. The three-dimensional imaging model of tracer particles is established according to the pinhole camera model and its corresponding point spread function. The simulated images of particles in the flow field illuminated by color volume light on the color camera are combined with the three-dimensional velocity field generated by the Rankine vortex model to obtain the simulated particle positions at different times. Rainbow particle image velocimetry is used to reconstruct the particle distribution field and particle velocity field of particles with different densities under different velocities of the Rankine vortex field. The AAE and AEPE of the reconstruction results are discussed. With the same particle density, AEPE increases with the speed of the particle, while AAE has the opposite trend. The value of AEPE decreases along with the particle density growth. The reason is that with the increase in the number of particles, the information in 3D reconstruction is more sufficient, which improves the accuracy of 3D reconstruction. Nevertheless, the particle density has little effect on AAE. The comparison between the reconstructed results and the real values shows that the simulated particle image generated by this method can provide support for the research of particle image velocimetry algorithms based on color illumination.
    Liang SHAN, Feiyang SHI, Bo HONG, Daodang WANG, Junzhe XIONG, Ming KONG. Particle Field Simulation Imaging for Color-illuminated Particle Image Velocimetry[J]. Acta Photonica Sinica, 2022, 51(3): 0311002
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