Top>Research and Development>Development of the evaluation method for the atomization mechanisms of a wall-impinging jet

For the severe accident management of nuclear reactors, predicting the behavior of molten fuels is important. In the case that the jet of molten fuels falls and atomizes, wall-impingement makes atomization behavior change and prediction more difficult. The Thermal Hydraulics Team succeeded in three-dimensional visualizing the behavior of jets simulating molten fuels and measuring its feature properties. However, to predict the behavior quantitatively, deep understanding and modeling of the phenomena are necessary.
In this study, to solve this subject, we developed a method to evaluate the mechanisms of atomization phenomenon by comparing measured values based on interfacial shape data with theoretical values. As a result of applying the method to the jet, atomization occurs by some mechanisms depending on the magnitude relationships among velocity difference between the jet and its surrounding fluid, gravity and a centrifugal force. Furthermore, the model formulas of droplet diameter and velocity, which we constructed to evaluate the mechanisms, can be useful for predicting jet behavior. Therefore, we built a technology base to evaluate the mechanisms of phenomena on the basis of three-dimensional interfacial shape data and deepened the understanding of the atomization phenomenon.
This outcome is due to research collaboration with University of Tsukuba.

The evaluation of the atomization mechanisms of a wall-impinging jet (Horiguchi, et al., 2025)

reference:Naoki Horiguchi, Hiroyuki Yoshida, Akiko Kaneko, & Yutaka Abe (2023) Atomization mechanisms of a wall–impinging jet in a shallow pool, Physics of Fluids 35, 073309
Naoki Horiguchi, Hiroyuki Yoshida, Akiko Kaneno & Yutaka Abe (2025) Atomization mechanisms in the vortex-like flow of a wall-impinging jet in a shallow pool, Physics of Fluids 37, 033333