中文摘要：

采用氢喷射温度下降法，数值模拟了氢氧火箭发动机高频燃烧不稳定现象。比较分析了混合比、室压和氢喷射温度对燃烧振荡的影响规律，得出了稳定性极限图及压力振荡频率变化规律。结果表明：氢喷射温度是影响燃烧不稳定的重要因素，降低氢喷射温度对燃烧稳定性不利，发生不稳定燃烧时，振荡主频呈倍频关系；混合比或室压增大，不稳定喷射氢温上升，即燃烧稳定性裕度较低；室压一定，存在一个特定的混合比，使得不稳定燃烧振荡主频最小；混合比一定，存在一个特定的室压，使得不稳定燃烧振荡主频最大。

英文摘要：

Based on the hydrogen-temperature-rating technique, the combustion instability in a LOX/GH2 liquid rocket engine is studied by computational fluent dynamics（CFD） methods. The effects of oxidant-fuel ratio, chamber pressure and hydrogen initial injection temperature on combustion oscillation at different operational conditions are compared and analyzed, and the combustion stability limiting map and the variable rules of instable pressure frequencies are obtained. Results show that hydrogen initial injection temperature is an important factor in instable combustion, lower temperature is disadvantageous to combustion stability and the instable dominant frequencies are present as multiple frequencies while the combustion instability happens. As the oxidant-fuel ratio or chamber pressure increased, the limit of the hydrogen initial injection temperature increased, in other words, the combustion stability decreased. In addition, the lowest instable dominant frequency is appeared at a certain oxidant-fuel ratio while chamber pressure is a constant. Contrarily, the highest instable dominant frequency is appeared at a certain chamber pressure while the oxidant-fuel ratio is a constant.