Photoluminescence-based simultaneous thermometry and velocimetry in non-aqueous liquid

• Published in: International Journal of Thermofluids 2023-08, Vol.19, p.100384, Article 100384
• Main Authors: Yamazaki, Masafumi, Hayashi, Tatsunori, Farahani, Hamed Farmahini, Rangwala, Ali S., Sakaue, Hirotaka
• Format: Article
• Language: English
• Subjects: Laser induced fluorescence; Particle imaging velocimetry; Simultaneous temperature and velocity measurement; Spatiotemporal measurement
• ISSN: 2666-2027; 2666-2027
• DOI: 10.1016/j.ijft.2023.100384

•This manuscript describes a simultaneous-measurement method based on laser-induced fluorescence (LIF) and particle-imaging velocimetry (PIV).•By employing europium tris [3-heptafluoropropylhydroxymethylene-camphorate] as temperature-sensitive probe and 1-pyrenecarboxylic acid as temperature-insensitive probe for the LIF-based thermometry, and pyranine-induced tracer particles for the PIV-based velocimetry, all three emission signals were simultaneously acquired by three color channels of a high-speed color camera to achieve a simultaneous temperature- and velocity-field measurement.•Toluene was chosen as a liquid to open the application of the proposed method to non-aqueous liquid.•As a demonstration of the proposed method, the natural convection process in the toluene solution was given.•The temperature sensitivity of the toluene solution was found to be -3.5%/°C at 0 °C with the measurement uncertainty of ±1.1 °C. The minimum and maximum velocities of the PIV-based thermometry were 1.6 and 36 mm/s for x-direction and 1.4 and 42 mm/s in y-direction, respectively. The heat transfer mechanism at the materials interface, such as gas-liquid, liquid-liquid, and solid-liquid interface, gives great insight into understanding the geometrical change in the interface over time. The temperature- and velocity-field measurements with respect to the liquid as the target material are essential to study the mechanism in spatiotemporal manner without disturbing an interaction region of the liquid. The simultaneous thermometry and velocimetry methods for non-aqueous liquid are studied and introduced based on the laser-induced fluorescence (LIF) and particle imaging velocimetry (PIV). Toluene is chosen as a non-aquatic liquid in which two different luminophores are dissolved. These two luminophores as well as the PIV particle emit at different wavelengths that are simultaneously acquired through three color channels of a high-speed color camera. The measurement system satisfying the proposed method is discussed and validated in a natural convection flow. [Display omitted]