Advanced understanding of local wetting behaviour in gas-liquid-solid packed beds using CFD with a volume of fluid (VOF) method

2017 ◽  
Vol 170 ◽  
pp. 378-392 ◽  
Author(s):  
Wei Du ◽  
Jianzhou Zhang ◽  
Panpan Lu ◽  
Jian Xu ◽  
Weisheng Wei ◽  
...  
Keyword(s):  
Volume Of Fluid ◽  
Vof Method ◽  
Packed Beds

scholarly journals 3-D numerical modelling of crustal polydiapirs with volume-of-fluid methods

2020 ◽  
Vol 222 (1) ◽  
pp. 474-506
Author(s):  
Aurélie Louis-Napoléon ◽  
Muriel Gerbault ◽  
Thomas Bonometti ◽  
Cédric Thieulot ◽  
Roland Martin ◽  
...  
Keyword(s):  
Volume Of Fluid ◽  
Vof Method ◽  
Earth’S Crust ◽  
Gravitational Instabilities ◽  
Interface Reconstruction ◽  
Rayleigh Taylor Instability ◽  
Earth's Crust ◽  
Two Stages ◽  
Rayleigh Benard ◽  
Earth Dynamics

SUMMARY Gravitational instabilities exert a crucial role on the Earth dynamics and in particular on its differentiation. The Earth’s crust can be considered as a multilayered fluid with different densities and viscosities, which may become unstable in particular with variations in temperature. With the specific aim to quantify crustal scale polydiapiric instabilities, we test here two codes, JADIM and OpenFOAM, which use a volume-of-fluid (VOF) method without interface reconstruction, and compare them with the geodynamics community code ASPECT, which uses a tracking algorithm based on compositional fields. The VOF method is well-known to preserve strongly deforming interfaces. Both JADIM and OpenFOAM are first tested against documented two and three-layer Rayleigh–Taylor instability configurations in 2-D and 3-D. 2-D and 3-D results show diapiric growth rates that fit the analytical theory and are found to be slightly more accurate than those obtained with ASPECT. We subsequently compare the results from VOF simulations with previously published Rayleigh–Bénard analogue and numerical experiments. We show that the VOF method is a robust method adapted to the study of diapirism and convection in the Earth’s crust, although it is not computationally as fast as ASPECT. OpenFOAM is found to run faster than, and conserve mass as well as JADIM. Finally, we provide a preliminary application to the polydiapiric dynamics of the orogenic crust of Naxos Island (Greece) at about 16 Myr, and propose a two-stages scenario of convection and diapirism. The timing and dimensions of the modelled gravitational instabilities not only corroborate previous estimates of timing and dimensions associated to the dynamics of this hot crustal domain, but also bring preliminary insight on its rheological and tectonic contexts.

An Improved Anti-Diffusive VOF Method to Predict Two-Fluid Free Surface Flows

2011 ◽  
Author(s):  
Y. G. Chen ◽  
W. G. Price ◽  
P. Temarel
Keyword(s):  
Free Surface ◽  
Diffusion Processes ◽  
Volume Fraction ◽  
Volume Of Fluid ◽  
Free Surface Flows ◽  
Vof Method ◽  
Advection Equation ◽  
Diffusion Term ◽  
Surface Flows ◽  
Two Fluid

This investigation continues the development of an anti-diffusive volume of fluid method [1] by improving accuracy through the addition of an artificial diffusion term, with a negative diffusion coefficient, to the original advection equation describing the evolution of the fluid volume fraction. The advection and diffusion processes are split into a set of two partial differential equations (PDEs). The improved anti-diffusive Volume of Fluid (VOF) method is coupled with a two-fluid flow solver to predict free surface flows and illustrated by examples given in two-dimensional flows. The first numerical example is a solitary wave travelling in a tank. The second example is a plunging wave generated by flow over a submerged obstacle of prescribed shape on a horizontal floor. The computational results are validated against available experimental data.

scholarly journals A Volume of Fluid (VOF) Method for the Simulation of Metallurgical Flows

2001 ◽  
Vol 41 (3) ◽  
pp. 225-233 ◽  
Author(s):  
Petar Liovic ◽  
Jong-Leng Liow ◽  
Murray Rudman
Keyword(s):  
Volume Of Fluid ◽  
Vof Method

CFD Simulation of an Aeroengine Bearing Chamber Using an Enhanced Volume of Fluid (VOF) Method: An Evaluation Using Adaptive Meshing

2014 ◽  
Author(s):  
Alexandre Crouchez-Pillot ◽  
Hervé P. Morvan
Keyword(s):  
Cfd Simulation ◽  
Adaptive Mesh ◽  
Volume Of Fluid ◽  
Vof Method ◽  
Physical Models ◽  
Adaptive Meshing ◽  
Displacement Pump ◽  
Aero Engines ◽  
Set Up ◽  
Cooling And Lubrication

In aero engines, the rotating shafts are supported by a set of bearings, which are enclosed in bearing chambers. Cooling and lubrication oil escapes from the bearings and these chambers are designed to capture and recycle it. A good understanding of the oil behaviour inside bearing chambers is therefore desirable in order to limit the oil volume involved and minimize transmission losses whilst managing the engine core heat in the best possible manner. This study is focused on the simulation of the oil behaviour inside such a chamber and special attention is given to the so-called KIT bearing chamber. The oil phase in the chamber can take different forms e.g. sprays, droplets, thin films or a combination of those. Assuming the oil we want to track remains dominantly as a film and large droplets/filaments, the Volume of Fluid (VOF) method is used in order to track the oil and the oil/air interface in the chamber, hereby investigating the feasibility and merits of such an approach and extending the earlier work carried out by the authors and colleagues. An Enhanced VOF approach coupled with level-set is used here unless stated otherwise. The simulated pump outlet condition, proposed by the University of Nottingham, is also employed in this study, to replicate an engine displacement pump. Since the use of VOF requires a refined mesh in the oil region, an adaptive mesh approach based on the volume of fluid gradient is developed and validated to control the total cell count for some of the cases reported here and limit simulation costs. The Adaptive Mesh Approach (AMA) can allow a better resolution of critical interfaces, better compute the oil break-up (within the limitation of the physical models used) and then track the droplets and filaments. Therefore, not only the CPU time cost might be reduced compared to a fixed mesh approach but significant physical aspects of the problem should be better accounted for. In order to inform the set up and parameters used with this method, and appraise its value for the proposed application, the experimental study of Fabre is used before the approach is applied to the KIT chamber. Good insight is obtained in terms of run time acceleration for such problem when combining the proposed VOF setup with adaptive meshing. Key set up parameters are quantified. The simulations carried out with the proposed set up are proving to be fairly robust and stable. Qualitative (physical) evidence is also encouraging and confirms the value of such an approach to the study of aeroengine bearing chambers.

Optimization of a High Pressure Swirl Injector by Using Volume-of-Fluid (VOF) Method

2010 ◽  
Author(s):  
Mohammad Rezaeimoghaddam ◽  
Hossein Moin ◽  
M. R. Modarres Razavi ◽  
Mohammad Pasandideh-Fard ◽  
Rasool Elahi
Keyword(s):  
High Pressure ◽  
Stokes Equations ◽  
Cone Angle ◽  
Volume Of Fluid ◽  
Liquid Sheet ◽  
Vof Method ◽  
Geometric Parameters ◽  
Orifice Diameter ◽  
Swirl Chamber ◽  
Pressure Swirl

In this paper, the effects of various geometric parameters of a high pressure swirl Gasoline Direct Injector (GDI) on the injection flow quality are investigated. The two-dimensional axisymmetric Navier-Stokes equations coupled with the Volume-of-Fluid (VOF) method were employed for simulation of the formation mechanism of the liquid film inside the swirl chamber and the orifice hole of the pressure swirl atomizer. To validate the model, results for base injector were compared in the steady state operation with those of available experiments in the literature. Good agreements were obtained for discharge coefficient (Cd) and cone angle (θ) with experimental data. The effects of five characteristic geometric parameters of swirl injectors such as orifice ratio (orifice length to orifice diameter), angle of swirl chamber, orifice diameter, needle lift and needle head angle (assumed to be cone) were investigated. The results show that increasing the swirl chamber angle leads to an increase in mass flow rate and a decrease of the cone angle of liquid sheet. Through extensive simulations, geometric parameters of an optimum injector were obtained.

Sign in / Sign up

Export Citation Format

Share Document