NUMERICAL SIMULATION OF VAPORIZATION IN MINICHANNELS USING MULTIPHASE VOF MODEL

Author(s):  
Ghazali Mebarki ◽  
Mourad Rebay ◽  
Nadim El Wakil ◽  
Anis Hamza ◽  
Samir Rahal
Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1606
Author(s):  
Maria Grazia Badas ◽  
Riccardo Rossi ◽  
Michela Garau

The present work aims to assess whether a standard numerical simulation (RANS-VOF model with k − ϵ closure) can adequately model experimental measurements obtained in a dam physical model. The investigation is carried out on the Sa Stria Dam, a roller compacted concrete gravity dam currently under construction in Southern Sardinia (Italy). The original project, for which a physical model was simulated, included a downstream secondary dam. However, due to both economic and technical reasons, the secondary dam may not be built. Hence, it is important to assess the flood discharge routing and energy dissipation in the modified plan. Numerical validation is performed adopting the same laboratory configuration, in presence of the downstream dam, and results show a good agreement with mean experimental variables (i.e., pressure, water level). An alternative configuration without the downstream dam is here numerically tested to understand the conditions of flood discharge and assess whether its results can give relevant information for the design of mitigation measures. The topic is of interest also from a more general perspective. Indeed, the feasibility to integrate numerical models with existing laboratory measurements can be very useful not only for new constructions but also for existing dams, which may need either maintenance or upgrading works, such as in case of flood discharge increment.


2013 ◽  
Vol 864-867 ◽  
pp. 2027-2030
Author(s):  
Shan Shan Lu ◽  
Hua Li ◽  
Hui Chao Dai ◽  
Quan Lin Ding

Falling-sill bottom-flow dissipation is an important energy dissipater way, which has two fluent characteristics, spatial 3D hydraulic jump and submerge jet. But the turbulent motion is strong with a flow pattern of complex level. It is hard to detail the hydraulic characteristics and strength being inside of the plunge pool using physical experiments. However, numerical simulation can match the deficiency of physical model, which has the access to detail flow field hydraulic characteristics and provide a strong scientific basis on analyzing the hydrodynamic and hydraulic characteristics of plunge pool. In this paper, XJB project is taken for example, gas-liquid two-phase flow tracking the simulation free surface of VOF model was used. The RNG κ_ε turbulent motion model is adequate to simulate the 3D flow field in plunge pool. The result shows that the consequence of numerical simulation and physic test match well, which can reflect the plunge pool hydraulic characteristics and dissipation process accurately. The distribution of flow speed inside the plunge pool locates the position of main flow and reflects the velocity decay along the way and reflux flow vortex .


2012 ◽  
Vol 516-517 ◽  
pp. 926-930
Author(s):  
Guang Li Xu

The flow characteristics of deposited water displaced by flowing oil in hilly terrain tube were studied experimentally and numerically. Lab-scale experiments were carried out on the transparent organic glass test loop with I.D. 50 mm to investigate the distributions of oil-water interface by diesel flowing from a lower horizontal test section into the up-inclined test section. Two-dimensional numerical simulation was conducted by VOF model and CSF model based on the test geometrical model. Comparisons of the oil-water interface distribution and the critical superficial oil velocity show that the numerical simulations favorably compare with the measurements.


2012 ◽  
Vol 479-481 ◽  
pp. 2380-2382
Author(s):  
Zheng Fu Zhang ◽  
Jun Wei Wang ◽  
Feng Bao

The jet water shape of the nozzle will become a self-oscillating shape, if the triangle and U shape models are made into the normal nozzle. Using the VOF model , the jet shape of the nozzle will be simulated through a commercial CFD software 'FLUENT'. The VOF model (Volume of Fluid) is a surface-tracking technique applied to a fixed Eulerian mesh. It is designed for two or more immiscible fluids where the position of the interface between the fluids is of interest. The CFD simulation results shows that the jet shape of the nozzle is oscillate in a fixed period.


2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Oumaima Eleuch ◽  
Zied Driss

A numerical simulation study was done on a penetrating pure water jet injected into another surrounding salt water miscible with negative buoyancy conditions. For the incompressible filtered Navier-Stokes equations and the sum of the fluid model volume, we used a transient Computational Fluid Dynamics (CFD) solver (VOF model). A finite volume discretization method using Open Source code given in Open Foam 2.3.0. was used to solve these equations. The flow has a significant impact in the laminar system on the evolution of the jet in terms of subsequent permanent phase as well as the transient regime.


2019 ◽  
Vol 53 (1) ◽  
pp. 97-106
Author(s):  
Bao-Ji Zhang ◽  
Jie Liu ◽  
Ning Xu ◽  
Lei Niu ◽  
Wen-Xuan She

AbstractA numerical simulation method is presented in this study to predict ship resistance and motion responses in regular and irregular waves. The unsteady RANS (Reynolds Average Navier-Stokes) method is selected as the governing equation, and a volume of fluid (VoF) model is used to capture the free surface, combining the k-ε equations. A finite volume method (FVM) is utilized to discretize both the RANS equations and VoF transport equation. The pressure implicit split operator (PISO) method is set as the velocity-pressure coupling equation. The overset mesh technique is utilized to simulate ship motions in waves. A DTMB5415 ship is selected as a case study to predict its pitch and heave responses in regular and irregular waves at different wave length and wave steepness. The ship is free to move in the pitch and heave directions. The CFD (Computational Fluid Dynamics) results are found to be in good agreement with the strip theory and experimental data. It can be found that the CFD method presented in this study can provide a theoretical basis and technical support for green design and manufacture of ships.


2000 ◽  
Author(s):  
Yuwen Zhang ◽  
Amir Faghri

Abstract Condensation in a capillary grooved structure is investigated using the Volume of Fluid (VOF) model. The governing equations are written in a generalized form and are applicable to both liquid and vapor phases. Condensation on the fin top and at the meniscus is modeled by introducing additional source terms in the continuity, VOF, and energy equations. The effects of temperature drop, contact angle, surface tension, and fin thickness on the condensation heat transfer are investigated.


2011 ◽  
Vol 317-319 ◽  
pp. 2085-2090
Author(s):  
Rang Shu Xu ◽  
Ling Niu ◽  
Xin Zhu Weng ◽  
Long Xu ◽  
Min Li Bai

For the purpose of increasing applicability of combustion chamber simulation, computational domain, boundary condition, simplicity of complicated structures, mesh generation and physical parameters are investigated in this paper. An annular combustion chamber of some aero-engine is studied by means of predictive numerical simulation. The computational domain includes diffuser, swirler, inner flame tube, inner ring of combustion chamber and the flow channel of all the holes on the wall of flame tube. The film cooling holes row was simplified into a slit filled with porous media. Realizable k-turbulent model and non-premixed combustion model were adopted. Model of pressure atomization nozzle were calibrated and validated through inner nozzle flow property two-phase flow VOF model and experimental data. Physical parameters are express through polynomial functions. A commercial CFD code was adopted on a high performance computing cluster with parallel algorithm and the solving method are high-order discretization scheme. The velocity, pressure, temperature, fuel spray, density of fuel and productions, etc. are calculated and validated with the experimental data.


2011 ◽  
Vol 327 ◽  
pp. 61-65
Author(s):  
Li Li Mu ◽  
Ning Xue

In order to research the effects of digital micro droplet injected by the piezoelectric ceramic inertial driver, the calculation model of micro flow field of micro injector was established based on the VOF model of multiphase flow. The calculation selected the implicit segregated solver and the standard k-e model was used in turbulence of the micro-nozzle. The governing equation was separated in first order upwind, and solved by PISO algorithm. The flow pattern of the micro channel fluid and the dynamic evolution process of the micro droplet generation in the plus wave driving were researched.


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