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Show RESULTS AND DISCUSSION Figure 5 shows the mean velocity field in the plane bisecting a jet for one of the model configurations studied. In this case the jet injection angle was 90°, the velocity ratio was 20 and the area reduction in the duct was 25%. The bulk velocities of the incoming primary flow and the secondary (jet) flow were 0.092 m/s and 1.840 m/s respectively. Examination of Figure 5 shows that the inlet velocity profile was not uniform. This non-uniformity results because the flow entering the combustor turns through a right angled bend. To guarantee a steady inlet velocity profile and allow examination of the injection jet mixing effects separated from the inlet profile effects, an upstream flow-straightener with a coarse mesh was installed. The flow straightener did not eliminate the inlet profiles but produced a similar inlet profile in all cases studied. However, the data analysis indicated that the inlet profile nonuniformity had no significant effects in the combustor mixing regions. Furthermore, in all cases where the velocity ratio was 20, the mass flow in the injection and downstream regions was symmetric about the centerline. In these cases most measurements were made below the cen-terline with a few measurements made above the centerline for reference purposes. In the case plotted in Figure 5 recirculation zones were formed both upstream and downstream of the secondary air injection jets. 0 75 i • .r. .,• • VELOCITY SCALE 1 M/S i 1 1 FT/S -H Figure 5. Velocity Field in Plane Bisecting a Jet. Jet Angle = 90° Area Reduction = 25%, Mass Ratio = 0.75, Velocity Ratio = 20, 9 |