“…Such side-loads have occurred during staging events of the Minuteman, Scout, Agena, Titan, PeaceKeeper, Small ICBM, and other systems in history. 3,4 Figure 1.Schematic of fire-in-the-hole staging event.…”
Section: Introductionmentioning
confidence: 99%
“…Sadunas et al. 3 developed an empirical approach to predict nozzle side-loads with nozzle blockage taken into account. Luke and Adams 4 presented the theoretical analysis and experiment results of reducing nozzle side-loads during staging using trip ring.…”
The objective of this effort is to numerically investigate the effect of the fire-in-the-hole staging event on the start-up flow separation and side loads of a conical nozzle during flight. The axisymmetric transient flow structure in nozzle was examined by time-accurate numerical method with time-varying chamber pressure and separation gap width. Three-dimensional time-accurate computations to examine the side loads due to non-nominal staging movement were conducted for two particular cases: misalignment between two stages and the angle of the nozzle thrust vector direction. Each asymmetry case comprised several specific staging state points which determined the corresponding chamber pressure and staging gap width. As presented by the simulation results, the flow separation in nozzle is significantly prolonged and intensified by the obstruction of the lower stage dome. When the flow separation location moves close to the nozzle exit, a strenuously axial oscillation of the separation shock appears and lasts for a period of time. In the three-dimensional asymmetric computations, in spite of strenuous oscillation, the time-average of nozzle side loads indicate that the asymmetric staging situation could lead to large sustained lateral disturbance forces. An essential ingredient driving the flow unsteadiness and asymmetry is related to the deflected and reversed supersonic flow by the dome and interstage wall corner of lower stage.
“…Such side-loads have occurred during staging events of the Minuteman, Scout, Agena, Titan, PeaceKeeper, Small ICBM, and other systems in history. 3,4 Figure 1.Schematic of fire-in-the-hole staging event.…”
Section: Introductionmentioning
confidence: 99%
“…Sadunas et al. 3 developed an empirical approach to predict nozzle side-loads with nozzle blockage taken into account. Luke and Adams 4 presented the theoretical analysis and experiment results of reducing nozzle side-loads during staging using trip ring.…”
The objective of this effort is to numerically investigate the effect of the fire-in-the-hole staging event on the start-up flow separation and side loads of a conical nozzle during flight. The axisymmetric transient flow structure in nozzle was examined by time-accurate numerical method with time-varying chamber pressure and separation gap width. Three-dimensional time-accurate computations to examine the side loads due to non-nominal staging movement were conducted for two particular cases: misalignment between two stages and the angle of the nozzle thrust vector direction. Each asymmetry case comprised several specific staging state points which determined the corresponding chamber pressure and staging gap width. As presented by the simulation results, the flow separation in nozzle is significantly prolonged and intensified by the obstruction of the lower stage dome. When the flow separation location moves close to the nozzle exit, a strenuously axial oscillation of the separation shock appears and lasts for a period of time. In the three-dimensional asymmetric computations, in spite of strenuous oscillation, the time-average of nozzle side loads indicate that the asymmetric staging situation could lead to large sustained lateral disturbance forces. An essential ingredient driving the flow unsteadiness and asymmetry is related to the deflected and reversed supersonic flow by the dome and interstage wall corner of lower stage.
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