OH(2,0) PLIF Measurement of the Flame Base in High-pressure H₂/O₂ Jet Diffusion Flame up to 5.0 MPa

This study focuses on the measurement of the flame base in a gaseous H-2/O-2 coaxial jet diffusion flame under highpressure (1.0-5.0 MPa) rocket combustion conditions. OH(2,0) band excitation was utilized for OH-planar laser-induced fluorescence (OH-PLIF) measurement to obtain the flame cross-section. The injection Reynolds number was varied under each pressure to examine the flame structure variation. Numerical simulation was also conducted to visualize the injector vicinity flow field. Results showed that the OH-PLIF measurements had sufficient signal intensity for evaluation. An analysis of the OH-PLIF images revealed variations in the flame thickness and the position of the flame edge under each condition. A numerical simulation of the cold flow was also performed to aid analysis of the OH-PLIF results.