Volume of fluid method

About: Volume of fluid method is a research topic. Over the lifetime, 5338 publications have been published within this topic receiving 116760 citations.

Nonlinear analysis of the deformation and breakup of viscous microjets using the method of lines

Abstract: SUMMARY We present a numerical model for predicting the instability and breakup of viscous microjets of Newtonian fluid. We adopt a one-dimensional slender-jet approximation and obtain the equations of motion in the form of a pair of coupled nonlinear partial differential equations (PDEs). We solve these equations using the method of lines, wherein the PDEs are transformed to a system of ordinary differential equations for the nodal values of the jet variables on a uniform staggered grid. We use the model to predict the instability and satellite formation in infinite microthreads of fluid and continuous microjets that emanate from an orifice. For the microthread analysis, we take into account arbitrary initial perturbations of the free-surface and jet velocity, as well as Marangoni instability that is due to an arbitrary variation in the surface tension. For the continuous nozzle-driven jet analysis, we take into account arbitrary timedependent perturbations of the free-surface, velocity and/or surface tension as boundary conditions at the nozzle orifice. We validate the model using established computational data, as well as axisymmetric, volume of fluid (VOF) computational fluid dynamic (CFD) simulations. The key advantages of the model are its ease of implementation and speed of computation, which is several orders of magnitude faster than the VOF CFD simulations. The model enables rapid parametric analysis of jet breakup and satellite formation as a function of jet dimensions, modulation parameters, and fluid rheology. Copyright q 2010 John Wiley & Sons, Ltd.

A comprehensive numerical investigation of unsteady-state two-phase flow in gravity assisted heat pipe enclosure

Abstract: In this study, thermal performance analysis of glass and copper two-phase closed thermosyphons (TPCTs) were investigated as 3D using comprehensive experimental methods and a new combined numerical model containing two stages. For this purpose, Volume of Fluid model has been used for the first 60 s, and Eulerian model has been employed after 60 s until 180 s for the first time in the literature. For the verification of this numerical analysis, the surface temperatures of TPCTs were measured at twenty different points by K-type thermocouples. The pressure change inside the pipes was measured by a vacuum manometer. A video camera was utilized to observe the change of steam and water volumes in the glass TPCT. The experimental and numerical results were also compared with each other in real-time for the first time in the literature. According to results, the numerical temperature distributions and steam volumes in TPCTs have shown a similar trend with the studies in the literature. It was observed that the maximum absolute temperature difference values in the evaporation, middle and condenser regions for TPCTs ranged from 6.81 K to 18.63 K. These values are similar to the values in the other studies. The maximum absolute temperature difference values were calculated between 12.09 K and 26.07 K for different turbulence models.