1. LDVmeasurements ofthe velocity field and Raman spectroscopy measurements of the major species fields in the flowfield described in Fig. 5 were measured at three axial measurement locations, viz. 25.4, 50.8 and 127 mm from the injector face. Examples of ten instantaneous uncorrectedfalse-color Raman line images for GO2, GH2and H2O species (GN2not shown) at an axial location of 25.4 mmfrom the shear coaxial injector face are shown in Fig. 6. Note that all images on this figure are atthe same axial location and that the vertical spacing is introduced only to distinguish the various measurements. Each of these images represents a cross-section cut through the annular flame in Fig. 5. In particular, each image illustrates (by color) the radial extent of species at the stated axial location at one instant of time. These instantaneous images show that at this axial station, GO2species is present only in the region downstream of the GO2post, whereas GH2species diffuses considerably in the radial direction. TheH2O species is present in the shear layer betweenthe GO2and GH2flows. The instantaneous Fig. 5. CFD predictions of the (a) velocity, (b) temperature and (c) OH concentration fields for the combusting GO./GH., flow/field downstream of the shear coaxial injector in the rocket chamber (see Figs. 1-2 for geometry and Table 1forflow conditions). Flow is from left to right. images also highlight the highly turbulent nature of the combusting shear layer. Analysis of the instantaneous flow structure in the combusting flowfield was not possible because the current experimental setup provided the Raman signal from only onespecies at atime.
2. To quantify the Raman spectroscopy measurements, the experimental setup was calibratedfor GO2, GH2and GN2species at standard temperature and pressure conditions. A similar calibration for H2O was obtained in a simple laboratory setup involving steam/air flow (393K). Usingthese calibrations, radial profilese of the major species mole fractions were extracted from the corrected/averaged Raman images. The resulting GO2and GH2mole fraction profiles for the three axial measurement locations are compared to the CFD results in Fig. 8. Similar comparisons for the mean velocity and rms velocity profiles are presented in Fig. 9. Forall inset graphs in Figs. 8-9, the ordinate shows the radial distance from the
3. The authors acknowledge funding from NASA Marshall Space Flight Center under Contract MAS 8-38862 and Cooperative Agreement Grant No. NCC 8-46. Funding from the Penn State Propulsion Engineering Research Center, Contract NAGW 1356 supplement 5 is also acknowledged. Finally, the authors thank Mr. L. Schaaf for his help in conducting the experiments and Dr. J. Grenda for his insightfulcomments.