Application of OH(2,0) Band Excitation Planar Laser-Induced Fluorescence to High-Pressure H2/O2 Jet Flames for Rocket Combustion

The purpose of this study was to develop an advanced method to measure the properties of rocket combustion using the OH(2,0) band-excited Planer Laser-induced Fluorescence (OH-PLIF) method. This diagnostic method was applied to capture images of the high-pressure H-2/O-2 jet diffusion flames found in typical liquefied bi-propellant rocket combustion. In addition, axisymmetric numerical simulations of H-2/O-2 jet flames modeling the experimental conditions were conducted to evaluate the consistency of the OH-PLIF imaging results and to predict the OH chemiluminescence intensity and flame temperature at high pressure. Experimental results show that it is possible to detect the OH(2,1) band fluorescence effectively by eliminating the interference of OH(0,0)-band chemiluminescence under high-pressure conditions of up to 2.0 MPa. The OH fluorescence signal distributed near the injector face almost corresponded to the OH molar concentration distributions simulated by numerical simulations. Moreover, the simulated pressure dependence of the local OH+ peak mole concentration reasonably corresponded to that of the local peak chemiluminescence intensity of the experimental chemiluminescence images.