Flow and Combustion Characteristics of Annular Advanced Vortex Combustor

To provide an optimized configuration of an annular advanced vortex combustor (AVC), a combined experimental and computational study was carried out about the flow characteristics of an AVC in a rectangular channel under the non-reacting flow condition. A detailed analysis was carried out about the flow through the AVC in a rectangular channel. On this basis, annular AVC model burning hydrogen was designed and consisted of an annular channel which was circumferentially arranged 18 pairs of blunt bodies between two cylinders. A numerical simulation study was conducted to provide understanding of the combustion characteristics of the annular AVC model. The results show: (1) By placing after-bodies, the wake shedding vortex of the flow behind fore-bodies can be effectively controlled and the resistance of the flow can be reduced in a rectangular channel; (2) The injection in the cavities reduces the drag effect depth of the shear layer on the flow in the cavities so that the vortex cores of the main vortexes shift outward the cavity in the AVC in a rectangular channel; (3) With the spacing between fore-body and after body increasing, the state of the main flow is basically kept unchanged and the drag effect of the shear layer on the flow in the cavities is enhanced in the AVC in a rectangular channel; (5) A reasonable configuration of an annular AVC can sustain steady combustion, and keep a low emission level, as the equivalence ratio of the premixed hydrogen and air is between 0.5 and 0.65. (6) Comparing the annular AVC with injection to that without injection, the vortex structures with injection are more symmetrical, the combustions are more stable, and the temperature distributions are more homogeneous. (7) The vortex structure in the annular AVC is almost not changed and the temperature distribution at the outlet alters into less uniformity with injection angle increasing.