Development of a xenon flashlamp induced fluorescence method to measure flowfield temperature and pressure

A nonintrusive method to measure temperature and pressure utilizing broadband excitation with broadband detection (BE-BD) of oxygen fluorescence was evaluated. The required finely-tuned laser excitation source for laser-induced fluorescence was replaced by a more rugged and less expensive xenon flashlamp. As a tradeoff, more lines were excited and, therefore, more fluorescence lines needed to be monitored.; Feasibility was proven by developing a numerical model simulating photon absorption and emission of oxygen and determining temperature and pressure sensitive fluorescence spectral regions. The spectral regions were located within a segment (200–300 nm) of the Schumann-Runge band. The two spectral bands selected were 5-nm wide and centered at 227.5 nm and 297.5 nm.; Proof of concept was done via a laboratory experiment in which the two 5-nm wide bins were monitored. The two bins were used to form a ratio to determine temperature. The resulting fluorescence ratio followed numerical predictions for temperatures between 80–170°C and pressures between 1 and 2 atm. The pressure was found by using the absolute values of each chosen bin scaled by the input intensity to remove pulse-to-pulse variations in the light source. The resulting temperature relation displayed errors less than 21% for temperatures greater than 90°C. The pressure relations were greatly affected by the errors in the calculated temperature and displayed a maximum error of 40%.