Diffusion Evolution of a Pore in Bounded Particle in a Hydrogen Atmosphere

Abstract

The problem of the diffusion evolution of a pore filled with molecular hydrogen in a spherical granule in a hydrogen medium is solved. The initial position of the pore is displaced relative to the center of the granule. A nonlinear system of equations is obtained, which describes the behavior of the size of the gas-filled pore, the amount of gas in it and its position relative to the center of the bounded particle with time. Numerical calculations have shown the existence of two stages of evolution. The first (fast) stage is associated with the equalization of pressure in the pore with the external. The second is the slow diffusion “healing” of the pore, when the amount of gas adjusts to its size and the gas pressure is approximately equal to the external.

Investigating the Effect of Gravity Modulation on Weakly Nonlinear Magnetoconvection in a Nonuniformly Rotating Nanofluid Layer

“…Expression (36) was first obtained by Kopp et al [28], which agrees very well with the known results. When there are no nanoparticles present (Rn = 0) , the expression (36) aligns with the findings reported by Kopp et al [25], [29]. In the absence of rotation ( Ta = 0 ) and a magnetic field ( Q = 0 ), Nield and Kuznetsov [33] derived the expression for the thermal Rayleigh number in the context of stationary motions.…”

“…In the absence of gravity field modulation, Eqs. ( 25)-( 29) were used to study the weakly nonlinear and chaotic regimes of stationary magnetic convection in a nonuniformly rotating "pure" (without nanoparticles) fluid, which were carried out by Kopp et al [25], [29]- [30]. Magnetic convection in a nonuniformly rotating "pure" (without nanoparticles) fluid under gravity modulation was studied by Kopp et al [31].…”