Simultaneous PIV/OH PLIF Measurements in Hydrogen Nonpremixed Flames with Coaxial Air

PIV/OH PLIF 동시 측정을 이용한 동축공기 수소확산화염의 실험적 연구

Simultaneous measurements of velocity and OH distribution were made using particle image velocimetry(PIV) and planar laser-induced fluorescence(PLIF) of OH radical in turbulent hydrogen nonpremixed flames with coaxial air. The OH radical was used as an approximate indicator of chemical reaction zone. The OH layer was correlated well with the stoichiometric velocity, $U_s$, instantaneously and on average. In addition, high strain-rate regions almost coincide with the OH distribution. The residence time in flame surface, calculated from the root-mean-square value of the radial velocity, is proportional to $(x/d_F)^{0.7}$. It is found that the mean value of principal strain rate on the OH layer can be scaled with $(x/d_F)^{-0.7}$ and therefore, the product of the residence time and the mean strain rate remains constant over all axial positions.