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

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.