Showing papers on "Volume of fluid method published in 2021"
TL;DR: In this paper, two kinds of water surface treatment, namely volume of fluids (VOF) and rigid-lid hypothesis (RLH) methods, for upstream and downstream reservoirs, are compared and corresponding results are compared.
72 citations
TL;DR: In this article, an improved free surface tracing method using the volume of fluid (VOF) technique was proposed to more effectively track the free surface of the molten pool with the computational fluid dynamics (CFD) software FLUENT.
Abstract: Ultra high-frequency pulsed gas tungsten arc welding (UHFP-GTAW)-based Wire Arc Additive Manufacturing (WAAM) was used to fabricate thin walls of NiTi shape memory alloys. The transient heat and fluid flow are critical during fusion-based additive manufacturing, since they impact the as-built microstructure. In this work, a three-dimensional numerical model, which includes the force, surface Gauss heat source and periodic droplet transfer models, was developed to simulate the deposition of 5 layers. The gravity, buoyancy, electromagnetic, surface tension, arc pressure and arc shear stress are considered in the developed force model. An improved free surface tracing method using the volume of fluid (VOF) technique was proposed to more effectively track the free surface of the molten pool with the computational fluid dynamics (CFD) software FLUENT. The multiphysic phenomena associated to the process, namely the temperature and velocity fields of the molten pool, were studied. The model was then validated by experiments. It is revealed that the microstructure of the as-built parts is refined by the UHFP current power which induces significant vibration of the molten pool. These findings lay the foundations for optimizing the WAAM process aiming at fabricating high quality and complex NiTi parts.
44 citations
TL;DR: In this paper, a fluid-structure coupling numerical model of an oil-jet lubricated cylindrical roller bearing (CRB) in a high power gearbox is developed, in which the volume of fluid (VOF) method and slip mesh model are used.
43 citations
TL;DR: In this paper, a single-connected pore space model was established by reconstructing the real micron CT scanned images of carbonate rocks, and the VOF (volume of fluid) method using FSF (filtered surface force) formulation was adopted on OpenFOAM platform to simulate the oil-water two-phase flow process at the pore scale.
40 citations
TL;DR: In this paper, a multiscale method was proposed to investigate the atomization characteristics of the pressure-swirl nozzle for dust reduction, which distinguishes between internal flow field, primary atomization and secondary atomization.
39 citations
TL;DR: This work represents the first successful application of a geometric VOF method coupled with a sharp-interface phase-change model and species transport to non-trivial problems, and represents an important step in the development of multiphase codes capable of accurately resolving complex three-dimensional multiphases flows.
35 citations
TL;DR: In this paper, thermal performance analysis of glass and copper two-phase closed thermosyphons (TPCTs) was investigated as 3D using comprehensive experimental methods and a new combined numerical model containing two stages.
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.
32 citations
TL;DR: In this article, a finite volume method was employed to numerically simulate two-phase flow by means of a finite-volume method and several decisive parameters including superficial gas velocity, channel surface wettability, and channel cross-section geometry were considered to find their effects on the liquid removal behavior.
31 citations
31 citations
TL;DR: Paris as mentioned in this paper is a finite volume code for simulations of immiscible multifluid or multiphase flows, where the interface separating the different fluids is tracked by a Front-Tracking (FT) method, or by a Volume-of-Fluid (VOF) method.
30 citations
TL;DR: In this article, the behavior of an incompressible fluid, sediment and solid particles debris at the time of a dam break was studied numerically on the basis of three-dimensional Reynolds-averaged Navier-Stokes equations in combination with the k-ω turbulence model.
TL;DR: In this paper, a numerical method to solve the incompressible Navier-Stokes equations for two-phase flows with phase change is presented. But the numerical difficulty of this jump is accommodated with the introduction of a novel two-step VOF advection scheme.
TL;DR: In this article, an advanced numerical investigation on the effect of surface wettability characteristics on single and multiple bubble growth during saturated flow boiling conditions within a micro-channel is performed, using the OpenFOAM toolbox.
TL;DR: In this article, a discretization of the Navier-Stokes equation that advects mass and momentum in a consistent manner is considered. But the method is not suitable for flow with large density contrasts.
TL;DR: In this paper, the advantages and disadvantages of micro and macro-channel flow boiling for high-heat-flux cooling applications using both computational and theoretical/empirical methods are examined.
TL;DR: In this paper, a computational fluid dynamics (CFD) based Unsteady Reynolds Averaged Navier-Stokes and Volume of Fluid model solver is adopted to estimate ship motion responses in bi-directional cross waves.
TL;DR: In this article, a computational fluid dynamics (CFD) solver modified from interFoam included in the open-source software OpenFOAM v.6 was used to simulate the direct contact condensation (DCC)-induced water hammering effect in previously designed steam pipes.
TL;DR: In this article, numerical simulation of a 2D Cryogenic Pulsating Heat Pipe (CPHP) is carried out, where liquid nitrogen is considered as working fluid and the volume fraction results of liquid nitrogen are studied for different operational conditions.
Abstract: Numerical simulation of a 2-D Cryogenic Pulsating Heat Pipe (CPHP) is carried out. Liquid nitrogen is considered as working fluid. The Volume of Fluid (VOF) model is used to simulate two-phase liquid–vapor flow in a CPHP. Filling Ratio (FR) is kept in the range of 25–70%. The evaporator temperature is set in the range of 85–115 K. The condenser temperature of 76 K is set constant. The volume fraction results of liquid nitrogen are studied for different operational conditions. A detailed qualitative and quantitative analysis is performed for working fluid temperature, adiabatic wall temperature and flow circulation velocity. Power spectrum density (PSD) and the Autocorrelation function (ACF) tools are used to analyze adiabatic wall temperature-time series data. Thermal oscillations are observed with dominant frequency in the range of 0.25–1.85 Hz.
TL;DR: In this article, the effects of heat transfer for a compressible time-dependent laminar flow pass the two distinctly positioned elliptic cylinders are examined numerically and the results of velocity distribution, pressure distribution, 2D temperature plots, isothermal contours, drag coefficient, streamlines and surface volume of fluid are discussed.
TL;DR: In this paper, a numerical model for analyzing the nonlinear interaction between the moored Submerged Floating Tunnel (SFT) and surface waves is presented, and an efficient mesh update method is employed to dynamically configure the computational meshes for viscous and incompressible free surface flows with the volume of fluid (VOF) method.
TL;DR: In this paper, a numerical investigation of water impact on the channel surface opposite to the GDL is carried out using the volume of fluid (VOF) method, and the effects of impact velocity, droplet size, surface contact angle, temperature and impact angle on the water impact process are investigated.
TL;DR: The method is applied to predict the growth of three-dimensional vapor bubble in a rectangular microchannel with boiling flow, achieving good agreement with experimental measurements and available simulation results using the level-set method.
TL;DR: In this paper, three-dimensional numerical simulations based on the Volume of Fluid method are conducted to investigate the hydrodynamic behavior of a falling film over horizontal round tubes with diameter and tube-to-tube spacings each of 16 mm.
01 Jan 2021
TL;DR: In this article, the primary atomization characteristics of liquid jet injected into a gaseous crossflow through direct numerical simulations (DNS) and large eddy simulations (LES) were studied.
Abstract: In this paper, we study the primary atomization characteristics of liquid jet injected into a gaseous crossflow through direct numerical simulations (DNS) and large eddy simulations (LES). The DNS use a coupled level set volume of fluid (CLSVOF) sharp interface capturing method resolving all relevant scales to predict the drop size distribution (DSD) for drops larger than the grid spacing. The LES use a volume of fluid (VOF) diffused interface method modelling the sub grid droplets. The purpose of this paper is to provide a comparison of the results of drop data between DNS and LES. The simulations are performed for a liquid jet injection with liquid-gas momentum flux ratio of 6.6, liquid jet Reynolds number of 14,000 injected into a crossflowing air with Reynolds number 570,000 and Weber number of 330 at a liquid-to-gas density ratio of 10. Two distinct and simultaneous atomization/breakup mechanisms have been observed in the simulations: column/bag breakup and ligament/surface breakup. It was found that the DSDs obtained from the DNS and LES each follow a log-normal distribution based on their respective droplet diameter data. An overlap region exists between the individual DSDs from the DNS and LES when combined. The width of this overlap region decreases along the downstream direction. A log-normal distribution is found to be a good fit to the combined DSD incorporating both resolved and sub-grid droplets. This information is relevant for the secondary atomization simulations and modeling.
TL;DR: In this article, a three dimensional numerical model is developed to model the thermal-fluid flow and to predict the surface morphology for the selective laser melting (SLM) process, which involves complex physics such as heat and mass transfer, phase transformation and molten pool flow.
TL;DR: In this article, a multiscale three-dimensional CFD model for simulation of two-phase gas-liquid flows with different interface length scales, with focus on slug flow pattern is presented.
TL;DR: In this article, high-speed (1s resolution) X-ray micro-computed tomography combined with pressure measurements recorded while controlling fluid flux was used to identify why intermittent fluid transport occurs at subsurface conditions and what the implications are for upscaled flow properties such as relative permeability.
TL;DR: Wang et al. as mentioned in this paper developed a 3D numerical model to study the droplet dynamic behaviors on super-hydrophobic NiTi surface, where the volume of fluid (VOF) method was carried out to track the multi-phase flow interface and then predict droplet shape evolution during the spreading, retraction and rebounding stages.
TL;DR: In this article, a numerical model based on the volume of fluid (VOF) method is established to describe the cavity and trajectory characteristics of an AUV with a high-speed water entry.