Investigation on cryogenic geyser characteristics in rocket cryogenic pipelines with a horizontal section

Geyser issues usually occur in cryogenic propellants transportation pipelines. However, the majority of research mainly focuses on the pipeline with only a vertical pipe section. In order to figure out the geyser behaviors and characteristics in more practical pipelines with both horizontal and vertical sections, a numerical investigation is performed to deeply analyze the two-phase flow appearance, energy storage patterns and thermal parameters oscillations. With a comprehensive comparison conducted between different pipeline configurations, some conclusions can be made as follows. A new geyser stage named horizontal condensation stage is found in the pipeline with both horizontal and vertical sections, and the horizontal condensation stage occupies 2.2% of the whole geyser period, sharing a similar proportion as the eruption stage. An interesting temperature peak can be formed in horizontal condensation stage, due to the heat absorption in the stratified vapor layer and the energy release in the horizontal condensation stage. Moreover, the occurrence of the horizontal condensation stage imposes contrary influences on geyser eruption intensity and refilling intensity. The eruption intensity is increased to be 1.44 times stronger compared to the pipeline with only a vertical section due to an enhanced energy storage ability. However, the refilling intensity is decreased, and the reason is speculated to be the buffering effect of the existence of the large amount of the vapor in the horizontal pipe section.