| OCR Text |
Show 1.92E-04 9.62E-OS O.OOE+OO 9 Baseline Boundary Layer Staging NO MASS FRACTION (DIMENSIONLESS) Figure 9 The fuel mass fraction plot clearly shows that internal flue-gas recirculation effects are occurring. This effect, coupled with a retarded fueUair mixing at the inner shear layer, results in almost a 400 degree reduction in flame temperature. Consequently, NOx levels drop appreciably. Burner Design The CFD model of the boundary layer staged burner dictated fuel injection in an axial direction close to the burner throat. However, this type of fuel injection results in a highly unstable flame front, causing flame out of the burner or severe furnace rumble. Therefore, to anchor the flame front, RJM Corporation designed highly stable, continuous, pseudo "gas pilots" known as mini stabilizers. This mini stabilizer system takes gas from the main gas ring and therefore remains ignited during all-burners-in-service operation. Locating one of the flame stabilizers immediately downstream of the existing gas igniter provides prompt and easy ignition. The final burner configuration is shown in Figure 10. |
