Abstract
A cavitation inception theory of a vapor bubble in flowing water is presented taking account of a set of fluid dynamics boundary conditions for nonequilibrium evaporation or condensation at the bubble wall. The boundary conditions are the ones for the vapor velocity and the vapor temperature at the wall, and are the solution of the polyatomic type of ES-BGK Boltzmann equation. The evaporation rate and the vapor-liquid temperature discontinuity at the wall can be correctly treated in a molecular level. The theory considers the translational motion of the bubble in flowing water with arbitrary relative velocity between the bubble and the water. The translational motion reduces the liquid pressure at the wall, and an inception process of cavitation is thereby influenced greatly. The liquid temperature at the wall is also essential for estimation of the evaporation rate, thus heat conduction equation for water is solved by two methods; one is analytical method using a similarity variable and another is numerical one based on the finite difference method.
