Measurement of Absolute Minority Species Concentration and Temperature in a Flame by the Photothermal Deflection Spectroscopy Technique

It is experimentally demonstrated that absolute concentrations of minority species in flames can be measured by the photothermal deflection spectroscopy (PTDS) technique. In addition, the PTDS signal simultaneously yields the flame temperature at the measurement point. Absolute concentration profiles of OH have been measured in a flatflame burner with methane as fuel. The PTDS measurements agree well with those obtained independently by the absorption technique. The flame temperature measurements by PTDS are also in good agreement with those obtained by the Boltzmann distribution among the rotational levels of OH.