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Vapor bubbles in cryogenic fluids may collapse violently under subcooled and pressurized conditions. Despite important implications for engineering applications such as cavitation erosion in liquid propellant rocket engines, these intense phenomena are still largely unexplored. In this paper, we systematically investigate the ambient conditions leading to the occurrence of violent collapses in liquid nitrogen and analyze their thermodynamic characteristics. Using Brenner’s time ratio χ, the regime of violent collapse is identified in the ambient pressure–temperature parameter space. Complete numerical simulations further refine the prediction and illustrate two classes of collapses. At 1 10 does the collapse show more inertial features. A mechanism analysis pinpoints a critical time when the surrounding liquid enters supercritical state. The ultimate collapse intensity is shown to be closely associated with the dynamics at this moment. Our study provides a fresh perspective to the treatment of cavitation in cryogenic fluids. The findings can be instrumental in engineering design to mitigate adverse effects arising from intense cavitational activities.

For the case of interaction of polarized light with an analyzer (a polarizing device), an experimental scheme based on the Feynman idea of path integrals is proposed. Real and virtual photons are considered in the context of the Lenz rule (in terms of constructive and destructive induction). The Planck formula for the photon energy in the format of a verbal description is considered. The complexity of identifying the wave description of the photon with the ideas of the Ancient Greeks about elementary particles is shown. From the point of view of chronogeometry, it is shown that the stationary observer does not exist at the point of intersection of the cone of the past and the future, but in the time interval separating these regions. It is proposed to consider the fluctuations of the physical vacuum as a relic of the process of permanent inflation according to Linde. Based on the assumption of the self-measurement of the Universe, the quantum Zeno effect, and Hawking’s idea of the Universe being a quantum object with the Nth sum of Feynman stories, it is assumed that the history of the Universe is deterministic. From the perspective of the orthogonality of the electromagnetic field vectors E and B, the Heisenberg equation of the form Δp × Δx = ħ/2 is considered. A thought experiment is considered showing the complexity in describing the interaction of a photon with an electron of an atom from the point of view of the classical interaction of an electromagnetic wave with an antenna device. It is proposed to consider the absorption of a photon by an electron as its inertial collapse on an atom.

• Numerical and theoretical analysis of intermediate vapor bubble collapse. • Intermediate collapse characterized by large temperature and pressure variation. • Effect of vapor velocity on the unique behavior of an intermediate collapse. • Analysis of the importance of rate of change in system pressure on collapse. • System of collapse uniquely defined with non-dimensional parameters, B sat and ξ. • Collapse categorization map based on B sat and ξ. This work presents a numerical and theoretical analysis of the intermediate bubble collapse, where in contrast to the thermally-induced or inertia dominated collapse, both the effects of liquid-vapor interfacial heat transfer and the advection of the surrounding liquid play an important role. A key distinguishing characteristic of this type of collapse is that the interfacial temperature and bubble pressure are continuously changing throughout the collapse process. This behavior is caused by a non-negligible value for the interfacial vapor velocity, which is characterized by a magnitude of the same order as the bubble surface regression rate. This behavior is in contrast to the inertial or thermal collapse, where, in these regimes, the vapor velocity is essentially zero. Incorporating the rate of change of background system pressure, a regime map for bubble collapse is also presented where the parameter space is defined by B sat and ξ and extends the previous categorization of Florschuetz and Chao (1965) where only B eff was used. Specifically, the present work quantitatively shows that the collapse behavior changes when the process is initiated by a gradual rate of pressurization in the surrounding liquid phase instead of the often used approximation of a step change. [ABSTRACT FROM AUTHOR]