Flow-Visualization Technique Combining the Laser-Induced Fluorescence and Dissociation of Iodine MOLECULES in Air Flows
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
Iodine molecules have high vapor pressure (25 mTorrs) at room temperature. This property, when combined with the strong fluorescence, makes iodine molecules ideal for air flow visualization. The 488 nm (>499 nm) and the 514.5 nm (<499 nm) emissions of the argon-ion laser are utilized to initiate dissociation and induce fluorescence, respectively. Specifically, the 488 nm emission dissociates the iodine molecules into iodine ATOMS in a localized area and the 514.5 nm emission induces fluorescence from the remaining iodine MOLECULES in the flow. The flow field is visualized from monitoring the motion of these iodine atoms. An arrangement implementing the above-mentioned principle is shown in the figure. Seeding of the flow with iodine molecules is readily achieved by passing the air through an iodine crystal reservoir.