Accurate measurement of fluid velocity distribution is crucial in the field of fluid mechanics research. The Planar Laser Induced Fluorescence Velocimetry (PLIF) system, as an advanced measurement technology, is playing an irreplaceable role and opening up a new window for researchers to observe the details of fluid flow.
The working principle of the planar laser-induced fluorescence velocimetry system is based on the phenomenon of laser-induced fluorescence. When a specific wavelength of laser is irradiated into a fluid containing fluorescent substances, the fluorescent substance molecules absorb the laser energy and transition to an excited state, and then emit fluorescence during the process of returning to the ground state. By measuring the spatial distribution of fluorescence intensity and combining it with known fluid dynamics models and optical principles, the velocity field information of the fluid can be inferred.
The system mainly consists of a laser light source, an optical transmission system, a fluorescence imaging system, and a data processing system. The laser beam generated by a high-energy, high pulse frequency laser source is shaped and expanded by an optical transmission system to form a thin sheet of laser light, which is uniformly irradiated on the fluid area to be measured. Fluorescent substances in the fluid are excited to produce fluorescence, and the fluorescence imaging system uses a high-speed camera to record a sequence of fluorescence images. The data processing system analyzes and processes the collected images, extracting information on the magnitude and direction of fluid velocity.
The planar laser-induced fluorescence velocimetry system has many significant advantages. Firstly, it can achieve full field measurement and obtain fluid velocity distribution over a large area at once, greatly improving measurement efficiency and spatial resolution compared to traditional single point measurement methods. Secondly, this technology is a non-contact measurement that does not interfere with the flow state of the measured fluid, ensuring the accuracy and authenticity of the measurement results. In addition, the PLIF system can also be combined with other measurement techniques, such as Particle Image Velocimetry (PIV), to further enrich measurement information and conduct in-depth research on complex fluid flow phenomena.
In practical applications, planar laser-induced fluorescence velocimetry systems are widely used in various fields such as aerospace, automotive engineering, biomedical engineering, etc. In the aerospace field, it can be used to study the airflow distribution around aircraft and optimize aircraft design; In automotive engineering, it is helpful to analyze the fuel spray and airflow movement inside the engine, and improve the engine performance; In the field of biomedical science, the ability to observe blood flow within human blood vessels provides important evidence for disease diagnosis and treatment.