Visualization of Supersonic Microjets Using LIF and MTV Techniques

14th International Conference on Fluid Control, Measurements and Visualization

Handa, Taro^1 ; Kambara, Hideto^2 ; Harada, Masaru^2

Department of Advanced Science and Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-Ku, Nagoya

468-8511, Japan^1

Department of Energy and Environmental Engineering, Kyushu University, 6-1 Kasuga-Koen, Kasuga

816-8580, Japan^2

关键词: Collapse location;    Micro jet;    Molecular tagging velocimetry;    Nozzle exits;    Planar laser induced fluorescence;    PLIF images;    Rectangular nozzle;    Visualization results;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/249/1/012016/pdf
DOI  :  10.1088/1757-899X/249/1/012016

来源: IOP

【 摘 要 】

Supersonic microjets issuing from a convergent rectangular nozzle whose height is 500 μm at its exit are visualized using the acetone-based PLIF (planar laser-induced fluorescence) and MTV (molecular tagging velocimetry) techniques. The jet Reynolds numbers are ranged between 200 and 7000 and the fully-expanded jet Mach-number is set to 1.5. The PLIF visualization results reveal that the jets spread abruptly at a certain location. Instantaneous MTV images are captured in the vicinity of the location where a jet spreads abruptly and the process of the jet collapse is successfully visualized. The distance between the nozzle exit and the jet-collapse location is estimated from each PLIF image. The distance is found to be constant for the Reynolds numbers higher than ∼700 and to be inversely proportional to the Reynolds number for the numbers lower than ∼700. Moreover, the distance changes abruptly at the Reynolds number of ∼700.