| A fixed-grid direct numerical simulation method has been developed and verified for single bubble dynamics, heat transfer and phase change phenomena. The original contribution of this research is the first introduction of a sharp interface between the vapor and liquid phases, which allows the simulation of density ratios up to the order of 1000. The interface location is obtained as part of the solution which accounts for all coupled dynamic and thermal effects.; The current method is believed to be the only method available at present which resolves the curvature calculation issue, treats the interface as a sharp discontinuity, honors the mass conservation principle, is capable of handling the large property ratios and phase change.; For the isothermal cases, the predictions of drag coefficients and the shape deformation of bubbles for Reynolds numbers ranging from 2 to 100 and Weber numbers from 2 to 20 were shown independently to agree with previous published results.; It was also demonstrated that the current method is capable of predicting accurate results for a wide range of Re, We, Ja, Pe numbers and property jumps at the interface.; For a stationary and growing bubble, the predicted growth rate was found to agree with the theoretical limit of ∝ t1/2 . However, for a rising and growing bubble, the predicted growth rate was approaching the theoretical limit of ∝ t 2/3 for a spherical bubble but did not reach it exactly owing to bubble deformation.; The empirical correlation proposed for bubble collapse is assessed by the simulations in the present work. The present numerical model predicts that the dynamics of a collapsing bubble is qualitatively, but not quantitatively similar to the empirical correlation proposed by other investigators. |
