Numerical analysis of highly underexpanded jets by multi-phase flows and sodium-water reaction analysis program seraphim

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

When the pressurized water leaks from a failed heat transfer tube in a steam generator of sodium cooled fast reactors, a highly underexpanded jet with sodium-water chemical reaction may cause wastage of the adjacent tubes. A computer program SERAPHIM for compressible multi-phase flows with sodium-water chemical reaction has been developed for safety assessment of the steam generator. In this study, numerical analysis of highly underexpanded jets was performed by using the SERAPHIM program to investigate its applicability. Through the analysis of the air jet into the air, it was demonstrated that the flow pattern and the location of a shock wave (Mach disk) were reproduced by the use of the high-resolution TVD scheme. Accuracy of the numerical results by the TVD scheme was higher than that by the first-order upwind scheme. Behaviors of the air jet into the water were also reproduced well in the present analysis.