Control Effects of Baffle on Combustion Instability in a LOX/GH2 Rocket Engine

摘要

The combustion instability encountered unexpectedly in hot-firing tests of the YF-960 liquid oxygen/gaseousnhydrogen (LOX=GH2) rocket engine was numerically researched. Here, the emphasis was on evaluating the controlneffects of two kinds of baffle configurations on combustion instability. The integrated physical model and numericalnmethod were presented to solve the turbulent, three-dimensional, two-phase, and full-size LOX=GH2 rocketncombustion process. The dominant oscillation frequency characteristics that appeared in the hot-firing tests werenreproduced and confirmed first, which validated the computational fluid dynamics code to a certain extent. The baffleneffects were investigated by the developed mass flow flux perturbing model. Results show that the control effect of thenhub-and-six-blade baffle on the one-order tangential-mode oscillation frequency of 5800 Hz is better than that of thenhub-and-three-blade baffle. Although the two kinds of baffles have similar effects on the radial-mode instability,nthe control effect is better for damping the 5800Hzoscillation than the 2900Hzoscillation. This research has providedndirect design data for engineers, and it is valuable in further understanding the baffle-eliminating mechanisms.