TRANSPORTABILITY OF A LASER-INDUCED FLUORESCENCE CALIBRATION FOR NO AT HIGH-PRESSURE

Obtaining quantitative measurements of NO concentration via laser-indu ced fluorescence (LIF) at high pressure requires application of a suit able calibration. While it is best to calibrate as close to the measur ement condition as possible, this is not always feasible. To assess th e transportability of a calibration factor at high pressure, we have c alculated ratios between linear LIF signals corresponding to a constan t NO concentration at different measurement and calibration conditions for high-pressure ethane flames. We find that pressure broadening lim its the utility of calibrating at a pressure different from that of th e measurement, although a calibration performed at a higher pressure i s applicable over a wider range of pressures than one performed at atm ospheric pressure. If one calibrates at the same pressure, it is best to calibrate at a temperature within 500 K of the measurement temperat ure. In general, the calculations indicate that a judicious choice of a calibration condition will guarantee a measured NO concentration wit hin a factor of two of the actual NO concentration.