Control Effects of Baffle on Combustion Instability in a LOX/GH_2 Rocket Engine

摘要

The combustion instability encountered unexpectedly in hot-firing tests of the YF-960 liquid oxygen/gaseous hydrogen (LOX/GH_2) rocket engine was numerically researched. Here, the emphasis was on evaluating the control effects of two kinds of baffle configurations on combustion instability. The integrated physical model and numerical method were presented to solve the turbulent, three-dimensional, two-phase, and full-size LOX/GH_2 rocket combustion process. The dominant oscillation frequency characteristics that appeared in the hot-firing tests were reproduced and confirmed first, which validated the computational fluid dynamics code to a certain extent. The baffle effects were investigated by the developed mass flow flux perturbing model. Results show that the control effect of the hub-and-six-blade baffle on the one-order tangential-mode oscillation frequency of 5800 Hz is better than that of the hub-and-three-blade baffle. Although the two kinds of baffles have similar effects on the radial-mode instability, the control effect is better for damping the 5800 Hz oscillation than the 2900 Hz oscillation. This research has provided direct design data for engineers, and it is valuable in further understanding the baffle-eliminating mechanisms.