光场三维速度和温度同步测量技术仿真分析

Simulation and analysis of simultaneous 3D velocity and temperature measurement technique based on light field imaging technology

  • 摘要: 本文提出了LF-PIV(单相机光场测速技术)与基于温敏磷光粒子衰减时间的测温技术相结合的三维速度和温度同步测量技术,实验校准了温敏示踪粒子(Mg3F2GeO4:Mn)光强衰减时间和温度的对应关系,仿真分析了相机曝光时间特性对测量准确性的影响。在相机两帧图像曝光时间可控条件下,利用DNS(Direct Numerical Simulation)得到的水射流数据进行数字合成图像仿真(射流温度及环境温度为均一温度343.15 K)。重构了三维粒子光强,反算了温度及速度场,分析了测量误差。在现有光场相机硬件参数条件下进行了可测量速度的理论分析及仿真研究。结果表明:在相机两帧图像曝光时间可控条件下,本文所提方法可实现三维速度和温度同步测量;但受现有光场相机硬件参数限制,目前可测量的速度较小。

     

    Abstract: A technique that can simultaneously measure three-dimensional velocity and temperature is proposed. The technique is based on LF-PIV(Single-camera Light-Filed Particle Image Velocimetry), and the temperature measurement technology making use of the lifetime of temperature-sensitive phosphorescent particles. The correspondence between the lifetime and temperature of the particle(Mg3F2GeO4: Mn)was experimentally calibrated, and synthetic light-field particle image simulation was performed to study the effect of camera exposure time characteristics on measurement accuracy. Under the condition that the exposure time of the two frames of camera is controllable, the water jet data obtained by DNS (Direct Numerical Simulation) are used for digital synthetic image simulation (the jet temperature and ambient temperature are 343.15 K uniformly). The three-dimensional particle image was reconstructed, temperature and velocity fields were calculated, and measurement errors were analyzed. In addition, a theoretical analysis and simulation study of the measurable velocity range was carried out under the existing light field camera hardware parameters. Simulation results show that, under the condition of controllable exposure time of two frames of camera, the new technique can simultaneously measure the three-dimensional velocity and temperature; however, the measur-able velocity is limited by existing light field camera hardware parameters.

     

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