Scaling criteria for IFE liquid wall protection scheme simulation

Abstract

Applicability of experimental results to a full-size system depends on the scaling criteria on which the test article/fluid medium is used. This paper presents a careful review and assessment of a number of key parameters which influence fluid stability phenomena relevant to the IFE wall protection schemes, and provides guidance for future simulation experiments. The analysis shows that the non-dimensional jet surface ripple size can be reproduced by simultaneously preserving prototypical jet Reynolds and Weber numbers. The results show the difficulties of using water as a simulant for liquid protectants in experiments for evaluating IFE thin and thick liquid wall protection schemes. The analysis also shows that a modified HTS salt seems a good simulant for Flibe and that liquid sodium a good simulant for liquid lead. However, in the absence of information on liquids other than water, serious questions remain concerning the issue of scaling. Nevertheless, to best utilizing the available R&D resources, further experiments should be performed using fluids with significantly lower vapor pressures, such as liquid metals or low-melting temperature salts or eutectics.

Study on flow instability for feasibility of a thin liquid film first wall

“…The predicted gas pressure at the critical condition of 10 m /s Pb-17Li liquid film flow, which is the typical velocity of the thin liquid metal film first wall concepts [9,11,22,23], is approximately 6.2×10 3 Pa. According to the recent study about the evaporation of liquid Pb-17Li [21], this pressure is attained at approximately 1600 K temperature and it is presumed as a probable value by previous studies [1,5,6,7,24].…”

“…Water liquid film was emitted from a 35-mmwide slit with a 0.5-mm gap and then flowed down along two 350-mm-long knife-edge guides. Many previous studies about the thin liquid film first wall, the film thickness was assumed between 0.5 mm and 1 mm [9,11,22,23]. To obtain enough gap and flow-width, gap and flow-length ratio, in this experimental, 0.5 mm was assumed.…”

“…This situation is unfavorable for maintaining a stable liquid film thickness. The merged wave number k sp can be described using each fastest wave number, as (9)…”

“…The second group of studies focuses on the fluctuation and stability of the liquid film, which is the approach taken in this study. Ying, Abdou [9] studied the criteria for fluid stability using the Reynolds number and the Weber number. Reperan, Yoda et al [10,11] observed flat flow stability and detachment, and Kondo, Suzuki et al [12,13] observed wave height distributions.…”