Experimental study of flow visualisation using fluorescent dye
Journal Publication ResearchOnline@JCUAbstract
Flow visualisation is an important and effective tool in the study of fluid dynamics as it is able to provide a quick visible presentation and qualitative and quantitative description of the entire real-time flow field of an unsteady flow. Some flow visualisation techniques have been used in a wide range of industries. Flow visualisation using a fluorescent dye is an effective technique to qualitatively investigate flow patterns for various configurations which usually involve low flow velocities and small lab scale geometries. In the present study, a Kármán vortex street flow at the Reynolds number of about 2520 was chosen to be visualised to investigate the performance of various dye types (fluorescein dye, rhodamine B dye, and blue food dye), dye tracer concentrations, and injection nozzle sizes, and post-processing techniques were used to extract quantitative pixel intensity data from the obtained flow pattern images. The analysis showed that the image intensity of the dye in the flow is dependent on the concentration and injection nozzle size. Visualisation results for 60 different arrangements were presented and analysed to ultimately conclude the superiority of fluorescein dye at a concentration of 1250 mg/L, for the flow visualisation considered. Additionally, it was found that the injection nozzles with the diameters of 0.51 mm and 0.9 mm allowed for a precise and natural release of dye into the inlet flow where the flow pattern was clearly presented downstream of the geometry. These outcomes provide some new and additional experimental evidences and data for the improvement of flow visualisation techniques.
Journal
Flow Measurement and Instrumentation
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Volume
87
ISBN/ISSN
1873-6998
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Pages Count
12
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Publisher
Elsevier
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EISSN
N/A
DOI
10.1016/j.flowmeasinst.2022.102231