In a propulsion system of cryogenic liquid rockets, low frequency pressure oscillation is an important topic on the oxygen jet condensation. It is a challenge to capture the numerical characteristic of pressure oscillation precisely, especially the frequency and amplitude. Aiming at the mechanism and excitation process of pressure oscillation, an oxygen jet condensation simulation is conducted by a novel mass transfer model based on the height function method. The height function method is used to calculate the interfacial curvature between gas-liquid, which is the key factor to determine the frequency of pressure oscillation. The new model is validated by a steam jet condensation simulation and the corresponding result is in great agreement with the experimental data. The research shows that the low frequency pressure oscillation is caused by the periodic condensation mass transfer rate of the continuous oxygen vapor plume, along with a GOX suck-back flow phenomenon in the gas inlet of condenser pipe. The excitation frequency of pressure oscillation is 10.6 Hz, consistent with the experiment data of engine test run. It is close to the natural frequency of propulsion system. It can be inferred that oxygen jet condensation might be one of the excitation source of self-excited Pogo vibration. These conclusions provide a theoretical basis for overcoming the Pogo vibration eventually.

在推进系统中在低温液体火箭中，低频压力振荡是氧射流凝结的重要课题。精确捕捉压力振荡的数值特征，尤其是频率和振幅，是一项挑战。针对压力振荡的机理和激发过程，采用基于高度函数法的新型传质模型对氧气射流凝结进行了模拟。高度函数法用于计算气液界面曲率，这是决定压力振荡频率的关键因素。通过蒸汽射流冷凝模拟验证了新模型，相应的结果与实验数据非常吻合。冷凝管进气口。压力振荡的激励频率为10.6 Hz，与发动机试车实验数据一致。它接近于推进系统的固有频率。可以推断，氧气射流凝结可能是自激Pogo振动的激发源之一。这些结论为最终克服Pogo振动提供了理论依据。