Study on critical speed of vortex rupture and gas-liquid two-phase flow in rotating soybean milk machine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Longhai Li ◽  
Hua-Shu Dou ◽  
Yu Du ◽  
Hongwei Guo ◽  
Hao Huang
Keyword(s):  
Critical Speed ◽  
Two Phase Flow ◽  
Stokes Equations ◽  
Vortex Breakdown ◽  
Central Axis ◽  
Navier Stokes ◽  
Phase Flow ◽  
Two Phase ◽  
Soybean Milk ◽  
Rotating Speed

AbstractThe gas-liquid two-phase flow field inside a soybean milk machine is simulated with the Navier–Stokes equations, Renormalization group (RNG) k-ɛ turbulence model and the particle two-phase flow model. The critical speed of vortex breakdown in the container and the influence of the characteristics of the two-phase flow on the soybean crushing effect at different speeds are investigated. The results show that there is a critical value of rotating speed of 1500 rpm for the vortex breakdown in the studied machine. At this rotational speed, the turbulent eddy dissipation (TED) reaches the maximum, and the position where the vortex first rupture is near the central axis and with a distance of 0.01 m from the central axis. It is also found that with the increase of rotating speed, the pressure difference around the blade varies significantly. The research in this study has important implication for the design of the soybean milk machine.

On convergent schemes for two-phase flow of dilute polymeric solutions

2018 ◽  
Vol 52 (6) ◽  
pp. 2357-2408 ◽  
Author(s):  
Stefan Metzger
Keyword(s):  
Finite Element ◽  
Two Phase Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Phase Flow ◽  
Two Phase ◽  
Extra Stress Tensor ◽  
Spring Force ◽  
Polymeric Solutions ◽  
Fokker Planck

We construct a Galerkin finite element method for the numerical approximation of weak solutions to a recent micro-macro bead-spring model for two-phase flow of dilute polymeric solutions derived by methods from nonequilibrium thermodynamics ([Grün, Metzger, M3AS 26 (2016) 823–866]). The model consists of Cahn-Hilliard type equations describing the evolution of the fluids and the unsteady incompressible Navier-Stokes equations in a bounded domain in two or three spatial dimensions for the velocity and the pressure of the fluids with an elastic extra-stress tensor on the right-hand side in the momentum equation which originates from the presence of dissolved polymer chains. The polymers are modeled by dumbbells subjected to a finitely extensible, nonlinear elastic (FENE) spring-force potential. Their density and orientation are described by a Fokker-Planck type parabolic equation with a center-of-mass diffusion term. We perform a rigorous passage to the limit as the spatial and temporal discretization parameters simultaneously tend to zero, and show that a subsequence of these finite element approximations converges towards a weak solution of the coupled Cahn-Hilliard-Navier-Stokes-Fokker-Planck system. To underline the practicality of the presented scheme, we provide simulations of oscillating dilute polymeric droplets and compare their oscillatory behaviour to the one of Newtonian droplets.

scholarly journals Slug Regime Transitions in a Two-Phase Flow in Horizontal Round Pipe. CFD Simulations

2020 ◽  
Vol 10 (23) ◽  
pp. 8739
Author(s):  
Vitaly Sergeev ◽  
Nikolai Vatin ◽  
Evgeny Kotov ◽  
Darya Nemova ◽  
Svyatoslav Khorobrov
Keyword(s):  
Pressure Drop ◽  
Flow Regime ◽  
Two Phase Flow ◽  
Stokes Equations ◽  
Bubbly Flow ◽  
Fluid Motion ◽  
Navier Stokes ◽  
Technical Solution ◽  
Phase Flow ◽  
Two Phase

The main objective of the study is to propose a technical solution integrated into the pipeline for the transition of the flow regime from slug to bubbly two-phase flow. The object of research is isothermal two-phase gas–Newtonian-liquid flow in a horizontal circular pipeline. There is local resistance in the pipe in the form of a streamlined transverse mesh partition. The mesh partition ensures the transition of the flow from the slug regime to the bubbly regime. The purpose of the study is to propose a technical solution integrated into the pipeline for changing the flow regime of a two-phase flow from slug to bubbly flow. The method of research is a simulation using computational fluid dynamics (CFD) numerical simulation. The Navier–Stokes equations averaged by Reynolds describes the fluid motion. The k-ε models were used to close the Reynolds-averaged Navier–Stokes (RANS) equations. The computing cluster «Polytechnic—RSK Tornado» was used to solve the tasks. The results of simulation show that pressure drop on the grid did not exceed 10% of the pressure drop along the length of the pipeline. The mesh partition transits the flow regime from slug to layered one, which will help to increase the service life and operational safety of a real pipeline at insignificant energy costs to overcome the additional resistance integrated into the pipeline.

Coupled solution of the Boltzmann and Navier–Stokes equations in gas–liquid two phase flow

2013 ◽  
Vol 71 ◽  
pp. 283-296 ◽  
Author(s):  
Sudarshan Tiwari ◽  
Axel Klar ◽  
Steffen Hardt ◽  
Alexander Donkov
Keyword(s):  
Two Phase Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Phase Flow ◽  
Two Phase ◽  
Navier Stokes Equations ◽  
Coupled Solution

An Improved Volume of Fluid Method for Two-Phase Flow Computations on Collocated Grid System

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Dong-Liang Sun ◽  
Yong-Ping Yang ◽  
Jin-Liang Xu ◽  
Wen-Quan Tao
Keyword(s):  
Two Phase Flow ◽  
Stokes Equations ◽  
Volume Of Fluid ◽  
Vof Method ◽  
Navier Stokes ◽  
Phase Flow ◽  
Volume Of Fluid Method ◽  
Two Phase ◽  
Navier Stokes Equations ◽  
Collocated Grid

An improved volume of fluid method called the accurate density and viscosity volume of fluid (ADV-VOF) method is proposed to solve two-phase flow problems. The method has the following features: (1) All operations are performed on a collocated grid system. (2) The piecewise linear interface calculation is used to capture interfaces and perform accurate estimations of cell-edged density and viscosity. (3) The conservative Navier–Stokes equations are solved with the convective term discretized by a second and third order interpolation for convection scheme. (4) A fractional-step method is applied to solve the conservative Navier–Stokes equations, and the BiCGSTAB algorithm is used to solve the algebraic equations by discretizing the pressure-correction equation. The above features guarantee a simple, stable, efficient, and accurate simulation of two-phase flow problems. The effectiveness of the ADV-VOF method is verified by comparing it with the conventional volume of fluid method with rough treatment of cell-edged density and viscosity. It is found that the ADV-VOF method could successfully model the two-phase problems with large density ratio and viscosity ratio between two phases and is better than the conventional volume of fluid method in this respect.

scholarly journals VOLUME-OF-FLUID MODEL COMFLOW SIMULATIONS OF WAVE IMPACTS ON A DIKE

2011 ◽  
Vol 1 (32) ◽  
pp. 17 ◽  
Author(s):  
Ivo Wenneker ◽  
Peter Wellens ◽  
Reynald Gervelas
Keyword(s):  
Flow Model ◽  
Two Phase Flow ◽  
Stokes Equations ◽  
Pressure Sensors ◽  
Navier Stokes ◽  
Phase Flow ◽  
Grid Cells ◽  
Two Phase ◽  
Navier Stokes Equations ◽  
Cpu Time

ComFLOW is a 3D Volume-of-Fluid (VOF) model to solve the incompressible Navier-Stokes equations including free surface, or to solve the Navier-Stokes equations for two-phase flow problems (two-phase flow: both an incompressible viscous fluid (e.g., water) and a compressible viscous fluid (e.g., air) are present). The problem statement of the present study reads: ‘Is ComFLOW capable of accurate prediction of wave impacts on (impermeable) coastal structures such as dikes? And, if so, what are the preferred model settings and associated computing times?’. In this paper, ComFLOW is validated for this purpose by comparison against pressure data as measured in the Delta flume by pressure sensors at dikes. We have selected three different experiments, with typical dike geometries (slope 1:3.5, with and without berm) at which more than 20 pressure sensors were installed. The results can be summarized as follows. The pressure measurements are reproduced well in the simulations. A grid with about 170 grid cells per wave length in the horizontal, and between 4 and 6 grid cells per wave height in the vertical, proves to be sufficiently fine. At such a grid resolution and with about 450 by 35 grid cells in the computational domain, a typical CPU time is 35 minutes for simulations with a model time of 10 wave periods. For the present application, it is preferable to use the one-phase flow model rather than the two-phase flow model, since the former gives better results in the lower located pressure sensors and consumes less CPU time.

A fast massively parallel two-phase flow solver for microfluidic chip simulation

2016 ◽  
Vol 32 (2) ◽  
pp. 266-287 ◽  
Author(s):  
Martin Kronbichler ◽  
Ababacar Diagne ◽  
Hanna Holmgren
Keyword(s):  
Adaptive Mesh Refinement ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Two Phase Flow ◽  
Stokes Equations ◽  
Adaptive Mesh ◽  
Navier Stokes ◽  
Implicit Time ◽  
Phase Flow ◽  
Two Phase

This work presents a parallel finite element solver of incompressible two-phase flow targeting large-scale simulations of three-dimensional dynamics in high-throughput microfluidic separation devices. The method relies on a conservative level set formulation for representing the fluid-fluid interface and uses adaptive mesh refinement on forests of octrees. An implicit time stepping with efficient block solvers for the incompressible Navier–Stokes equations discretized with Taylor–Hood and augmented Taylor–Hood finite elements is presented. A matrix-free implementation is used that reduces the solution time for the Navier–Stokes system by a factor of approximately three compared to the best matrix-based algorithms. Scalability of the chosen algorithms up to 32,768 cores and a billion degrees of freedom is shown.

2D Navier-Stokes stability computations for solid rocket motors - Rotational, combustion and two-phase flow effects

1997 ◽  
Author(s):  
Eric Daniel ◽  
Nicolas Lupoglazoff ◽  
Francois Vuillot ◽  
Thierry Basset ◽  
Joel Dupays ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Navier Stokes ◽  
Phase Flow ◽  
Two Phase ◽  
Solid Rocket Motors ◽  
Rocket Motors ◽  
Flow Effects ◽  
Solid Rocket
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