Numerical study on the effect of mass flux on the low frequency pressure oscillation occurred in oxygen jet condensation

Abstract

In the delivery pipeline of cryogenic liquid rockets, low‐frequency pressure oscillation always occurs with the oxygen jet condensation. It is a potential hazard to the normal operation of the propulsion system. It is necessary to study the characteristic of low‐frequency pressure oscillation precisely, especially the influence factors of frequency and amplitude. Aiming at the effect of mass flux on low‐frequency pressure oscillation, an oxygen injection condensation simulation is carried out based on a modified mass transfer model. The height function method is adopted to calculate the interfacial curvature, which is the key factor to capture the characteristic of pressure oscillation. The numerical result indicates that there are two typical oxygen jet condensation patterns under different mass fluxes: suck‐back chugging and slight pulsation. The amplitude of suck‐back chugging is 30–120 kPa, while that of slight pulsation is 1–3 kPa. When it comes to suck‐back chugging, the liquid oxygen suck‐back flow phenomenon occurs. The upper and lower boundaries are found to distinguish the suck‐back chugging and slight pulsation patterns, which are caused by the turbulent effect of liquid oxygen and the subcooling of liquid oxygen, respectively. The highest amplitude of pressure oscillation is about 114 kPa, appearing at the intersection of the upper and lower boundary. It is the most dangerous operation condition, which should be avoided in the design of the propulsion system. These conclusions provide sufficient theoretical guidance for the design of the cryogenic liquid rocket.