摘要: An experimental investigation of the influence of combustor annulus radii on RDRE wave dynamics with flat-faced impinging injectors has determined the fueling conditions at which mode transitions will take place and other operatin... 展开 An experimental investigation of the influence of combustor annulus radii on RDRE wave dynamics with flat-faced impinging injectors has determined the fueling conditions at which mode transitions will take place and other operating characteristics. To facilitate the isolation of all but the radius of curvature effects in the experiments, the annular gap was kept constant at 5 mm in combustors having either 25-mm, 51-mm, or 76-mm outer diameter. The injectors were scaled so that their net injector-to-gap area ratio was kept constant at AR = 0.11 with constant jet impingement height of 2.16 mm. The methane-oxygen propellant flow rates were adjusted at each RDRE size scale for mass flux (ψ) sweeps at constant equivalence ratio (φ) and φ sweeps at constant ψ. The operating modes of the RDREs were characterized by the number of co-rotating waves and whether or not a counter-rotating wave was present. At constant equivalence ratio of φ～ 1.15, ψ weeps indicated that the mode transitions occurred at the same values of ψ in these three RDREs. Likewise, at constant mass flux of ψ= 240 kg/s/m~2, φ sweeps indicated that the mode transitions occurred at similar values of φ. The wave number at a given ψ and φ differed by one between each size scale whenever a counter-rotating wave was not present. Whenever a single wave could not travel at the spin speed required to consume all the propellant, a counter-rotating wave appeared. One key conclusion is that combustor wave dynamics adjusted to accommodate the fueling conditions independent of the radius of curvature for these RDREs at mass fluxes greater than 320 kg/s/m~2. At lower mass flux and under very fuel-lean and fuel-rich conditions, variations in operating characteristics indicated that the radii of curvature had some influence. Experimental data from the three RDREs are presented within the propellant flux range of 80 kg/s/m~2 ＜ ψ＜ 400 kg/s/m~2 and equivalence ratio range of 0.25 ＜ φ＜ 2.6. 收起