| OCR Text |
Show in both cases is between 500 and 600 K. Although this is sufficiently low to reduce additional NOx production, it is also too low to promote further conversion of CO-to-C0 2. As illustrated in Fig. 10, heat transfer rates for both processes are initially high near the injectors, nearly uniform near the wall, and substantially higher at the chamber exit. The higher momentum secondary air, INSIDE JET : H • 0 · 05 " U • 3D "/SEC T· · 1100 l ouTSI DE JET : H • 0 ·020 " II • ~o " /SEC T • 500 l r"M. 2.I--4--------X/H· 10 ·2---------- ~~~iiij~iI-lL I ~--------~--------~~ Fig. 8 - Surface and contour plots of temperature distribution for 2-D coaxial jets expanding into a cavity. Slower outside jet . I ~SI DE JET : H • 0 ·05 " U • 3D "/SEC T • 1100 l OUTS I DE JET : H • o . o~o " U • 20 "/SEC T • 500 l 111M • 2·1 -+\ _________ X/H • 10 .2---------1 CONTOUR I NIERVAL • o. OS Fig. 9 - Surface and contour plots of temperature distrfbution for 2-D coaxial jets expanding into a cavity. Faster outside jet. 115 however, produces much higher rates near the inlet. Since NOx is generated in regions of high heat flux, Case 2 conditions indicate a greater potential for additional NOx production. Furthermore, since the upstream recirculation region of Case 2 is substantially larger, and the centerline temperatures are generally lower, slightly higher outlet co levels might be anticipated. INSIDE J[I : H • 0 ·05 " U • 3D M/ ~Er T • 1100 K OUTSIDE JET . H • O. O~O M U • 10 MIser T • 500 r Fig. lOa - Comparison of turbulent heat flux distributions for 2-D coaxial jets expanding into a cavity. Slower outside jet. I NSI or JET : H • 0. 05 M U • 30 Ml sEC T • 1700 K OIJlSIOE JET · H • 0 · 010 M U • ~O MlsEC T • 500 K Fig. lOb - Comparison of trubulent heat flux distributions for 2-D coaxial jets expanding into a cavity. Faster outside jet. SUMMARY The basic elements of a design and analysis methodology for thermal processing systems have been discussed. The keystone of the approach is the TEACH-3E/ll numerical simulation code for three dimensional turbu- |
