Experimental Study on Cryogen Injection Into Water

Abstract

Abstract. Explosive boiling is a hyperactive boiling phenomenon, which is characterized by transient high heat flux. There are still few researches on the experimental comparative analysis on explosive boiling inducing by different cryogen liquid injection into water. In this paper, to advance our understanding of LNG (Liquefied Natural Gas), LN 2 (Liquefied Nitrogen) and LC 3 H 8 (Liquefied Propane) injection into water process, a visualization experimental system is built. Visualized results show that LNG and LN 2 injection processes undergo a similar boiling, that is explosive boiling, which is characterized by bubbles cloud that strengthens heat transfer rate. LC 3 H 8 injection into water triggers subcooled flow boiling. There is no significant breaking on the liquid cryogen column and without bubbles cloud. The maximum heat transferring flux can be over 1.9 MW/m 2 in the condition of LNG injection into unconfined water and under the pressure of 7 bars. In order to investigate the determinant factors for explosive boiling occurring, instability of Rayleigh-Taylor, Kelvin-Helmholtz, Weber number and Marangoni convection are analyzed and used to explain the differences of maximum pressure and its occurring time in different experimental conditions such as injection depth into water, injection pressure, water temperature and injecting fluid. As a result, it is reasonable to conclude that if the relative velocity between cryogen and surrounding fluid is high enough, the breaking of liquid column or droplets will be defined by the Kelvin-Helmholtz instability and Weber number. And in subcooling mixture or pure substance injection process, the periphery of the vapor film near the head of column is considerably stronger than other regions in the effect of Marangoni convection at the beginning of column floating upwards or the ending of column going downwards. All of these can be seen as the key factors to improve heat transfer capacity and trigger explosive boiling.

Liquid Hydrogen Spills on Water—Risk and Consequences of Rapid Phase Transition

“…One could argue that the absence of delayed LIN RPT further strengthens the conclusion that delayed LH 2 RPT is impossible, since the Leidenfrost temperature and density of LIN is higher than for LH 2 . Subsurface injection of LIN into water has also been studied [53][54][55], and RPTs in such scenarios was observed. Bang and Corradini [52] measured quite low pressures during LIN RPT (1-2 bar).…”