Simultaneous measurement of concentration fluctuations of two species using pulsed laser diodes in light absorption spectrometric method

Abstract

In this study, we developed a simultaneous measurement system for measuring the concentration fluctuations of two species using pulsed laser diodes in the light absorption spectrometric method. Conventional methods utilize halogen lamps or continuous laser diodes as light sources for concentration measurements. These light sources require multi-monochrometers or dichroic mirrors, which makes these methods rather expensive. However, using pulsed laser diodes as the light sources eliminates the need for additional multi-monochrometers and dichroic mirrors. A diffusion field consisting of two dye species in an axisymmetric turbulent jet was measured using the developed concentration measurement system. To ascertain the validity of our concentration measurements, we compared the present measurement results with those of a single dye species and previous studies. It was observed that the concentrations of the two dye species were measured accurately by the present measuring system. Therefore, such low-cost concentration measurement systems can be developed and applied in various simultaneous measurements of concentration fluctuations of multiple species such as in turbulent reactive flows.

Keywords

• concentration measurement
• light absorption spectrometric method
• laser diode
• turbulent jet
• diffusion