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

Abstract

The combustion instability encountered unexpectedly in hot-firing tests of the YF-960 liquid oxygen/gaseous hydrogen (LOX=GH2) 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=GH2 rocket combustion process. The dominant oscillation frequency characteristics that appeared in the hot-firing tests were reproduced andconfirmedfirst,which validated the computationalfluiddynamics code to a certain extent. Thebaffle effects were investigated by the developedmass flow flux perturbingmodel. 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 fordamping the5800Hzoscillation than the2900Hzoscillation.This researchhasprovided direct design data for engineers, and it is valuable in further understanding the baffle-eliminating mechanisms.