|Budget Amount *help
¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 1998 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1997 : ¥2,500,000 (Direct Cost : ¥2,500,000)
Local chemiluminescence measurements of OH*, CH* and C2* radicals were carried out in turbulent premixed methane flame to make clear the details of flame-front structures and chemical reactions in the reaction zone. For this measurement, specially designed Cassegrain Optics, which has a high spatial resolution as small as an LDV measurement volume, was developed. Furthermore, to achieve a high temporal resolution, each chemiluminescence was detected by PM tube at sampling rate of 250kHz.
Simultaneous measurements of these three radicals and velocity by LDV were performed to obtain flame-front structure, flame propagating speed and flame thickness. Local Damkoler number were measured directly at the flame-front and their fine scale were demonstrated.
The probability density function (PDF) of OH* emission showed bi-modal peaks across the flame-front location corresponding to wrinkled laminar flame or flamelet region. The first peak of the OH* PDF was corresponding to the high temperature r
egion outside of the flame cone and the secondary peak was associated with chemical reaction at the primary reaction zone. Time series signals of local OH*, CH* and C2* emission intensities in wrinkled laminar flame region showed irregular peaks which, however, correspond to each other in the three chemiluminescence signals. This results indicated strong linkage between OH-C H-C2 reactions at wrinkled laminar flame-front. The flame-front thickness measured by CH and C2 emissions were 0.1-0.3mm, while that was about 1.0mm by OH* emissions. Furthermore, local reaction rate and local mixture strength at turbulent flame-front are examined from local CH* and C2* emission intensities in comparison with measured data bases of these emissions in laminar premixed flame.
A new optical diagnostics to examine local flame-front structure and flame chemistry by means of local chemiluminescence measurement was proposed and its performance was proven.
・ 乱れの弱いしわ状層流火炎ではOH^*自発光帯の厚さがCH^*,C2^*自発光帯の厚さの数倍程度厚くなった。 Less