Development of a numerical method for compressible multi-phase flows including highly underexpanded jets

Uchibori, Akihiro ; Ohshima, Hiroyuki; Watanabe, Akira*

Numerical analysis of highly underexpanded jets was performed by using a computer program SERAPHIM to investigate its applicability. When the pressurized water or water vapor leaks from a failed heat transfer tube in a steam generator of sodium cooled fast reactors, the multi-phase jet flow with sodium-water chemical reaction may cause wastage of the adjacent tubes. The SERAPHIM program has been developed for the simulation of the reaction jet. In the present work, the multi-fluid model, the constitutive equations modified for high-pressure or high-velocity conditions, the second-order TVD scheme and the HSMAC method considering compressibility were combined. In the case of the air jet into the air, the calculated pressure, the shape of the jet and the locations of a Mach disk agreed with the existing experimental results very well. Behaviors of the air jet into the water and the effect of the pressure change on the penetration length of the jet were also reproduced.