Velocimetry and thermometry in intermediate temperature flow using planar laser-induced fluorescence of OH from photo-dissociation of H2O

A technique for simultaneous velocimetry and thermometry in intermediate temperature flow is developed by combining hydroxyl-tagging velocimetry (HTV) and two-line OH planar laser-induced fluorescence (OH-PLIF). The OH tagging particles generated in HTV from the dissociation of water vapor are then used in two-line PLIF for thermometry. Using fragmentary OH expands PLIF to thermometry in regions that lack original OH, such as low temperature or unreactive ones. Meanwhile, using the PLIF system for both velocimetry and thermometry makes for a more efficient experimental system. As a proof of concept, the temperature and velocity are measured of a heated gas mixture comprising helium and water vapor. The temperature results agree well with the thermocouple results. [Graphical abstract]