A Computational Fluid Dynamics (CFD) Analsysis of the Vacuum De-Zincing Process

2003 ◽  
Author(s):  
V. Jalili ◽  
C. Bailey ◽  
M. K. Patel
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Metal Bath ◽  
Navier Stokes Equations ◽  
Modeling Process ◽  
Novel Approach ◽  
Computational Fluid Dynamics Cfd ◽  
Efficient Recovery

This is a novel application of Computational Fluid Dynamics (CFD), in the vacuum De-zincing process. The complete modeling process would involve the solution of the following equations: a) Navier-Stokes Equations; b) The Energy Equation; c) The Solution of the Species Concentration. The aim of this research as a novel approach in vacuum Dezincing process has been to gain an understanding in terms of the actual complicated physics involved de-zincing process such, as phase change and solidification. The results in this paper have contributed to a better understanding of the vacuum De-zincing process, hence identifying parameters, which would aid the efficient recovery of the zinc from the molten metal bath.

Development of SIMPLE-Like Algorithms for Incompressible Navier-Stokes Equations in Liquid Processing of Materials

2012 ◽  
Vol 184-185 ◽  
pp. 944-948 ◽  
Author(s):  
Hai Jun Gong ◽  
Yang Liu ◽  
Xue Yi Fan ◽  
Da Ming Xu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Stokes Equations ◽  
Simple Algorithm ◽  
Navier Stokes ◽  
Incompressible Fluid Flow ◽  
Numerical Accuracy ◽  
Simple Scheme ◽  
Navier Stokes Equations ◽  
Computational Fluid Dynamics Cfd

For a clear and comprehensive opinion on segregated SIMPLE algorithm in the area of computational fluid dynamics (CFD) during liquid processing of materials, the most significant developments on the SIMPLE algorithm and its variants are briefly reviewed. Subsequently, some important advances during last 30 years serving as increasing numerical accuracy, enhancing robustness and improving efficiency for Navier–Stokes (N-S) equations of incompressible fluid flow are summarized. And then a so-called Direct-SIMPLE scheme proposed by the authors of present paper introduced, which is different from SIMPLE-like schemes, no iterative computations are needed to achieve the final pressure and velocity corrections. Based on the facts cited in present paper, it conclude that the SIMPLE algorithm and its variants will continue to evolve aimed at convergence and accuracy of solution by improving and combining various methods with different grid techniques, and all the algorithms mentioned above will enjoy widespread use in the future.

scholarly journals A Massively Parallel Hybrid Finite Volume/Finite Element Scheme for Computational Fluid Dynamics

Mathematics ◽  
2021 ◽  
Vol 9 (18) ◽  
pp. 2316
Author(s):  
Laura Río-Martín ◽  
Saray Busto ◽  
Michael Dumbser
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Finite Element ◽  
Mach Number ◽  
Finite Volume ◽  
Degrees Of Freedom ◽  
Stokes Equations ◽  
Massively Parallel ◽  
Navier Stokes ◽  
Navier Stokes Equations

In this paper, we propose a novel family of semi-implicit hybrid finite volume/finite element schemes for computational fluid dynamics (CFD), in particular for the approximate solution of the incompressible and compressible Navier-Stokes equations, as well as for the shallow water equations on staggered unstructured meshes in two and three space dimensions. The key features of the method are the use of an edge-based/face-based staggered dual mesh for the discretization of the nonlinear convective terms at the aid of explicit high resolution Godunov-type finite volume schemes, while pressure terms are discretized implicitly using classical continuous Lagrange finite elements on the primal simplex mesh. The resulting pressure system is symmetric positive definite and can thus be very efficiently solved at the aid of classical Krylov subspace methods, such as a matrix-free conjugate gradient method. For the compressible Navier-Stokes equations, the schemes are by construction asymptotic preserving in the low Mach number limit of the equations, hence a consistent hybrid FV/FE method for the incompressible equations is retrieved. All parts of the algorithm can be efficiently parallelized, i.e., the explicit finite volume step as well as the matrix-vector product in the implicit pressure solver. Concerning parallel implementation, we employ the Message-Passing Interface (MPI) standard in combination with spatial domain decomposition based on the free software package METIS. To show the versatility of the proposed schemes, we present a wide range of applications, starting from environmental and geophysical flows, such as dambreak problems and natural convection, over direct numerical simulations of turbulent incompressible flows to high Mach number compressible flows with shock waves. An excellent agreement with exact analytical, numerical or experimental reference solutions is achieved in all cases. Most of the simulations are run with millions of degrees of freedom on thousands of CPU cores. We show strong scaling results for the hybrid FV/FE scheme applied to the 3D incompressible Navier-Stokes equations, using millions of degrees of freedom and up to 4096 CPU cores. The largest simulation shown in this paper is the well-known 3D Taylor-Green vortex benchmark run on 671 million tetrahedral elements on 32,768 CPU cores, showing clearly the suitability of the presented algorithm for the solution of large CFD problems on modern massively parallel distributed memory supercomputers.

scholarly journals Spectral Wave Explicit Navier-Stokes Equations for wave-structure interactions using two-phase Computational Fluid Dynamics solvers

2021 ◽  
Vol 221 ◽  
pp. 108513
Author(s):  
Zhaobin Li ◽  
Benjamin Bouscasse ◽  
Guillaume Ducrozet ◽  
Lionel Gentaz ◽  
David Le Touzé ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Stokes Equations ◽  
Wave Structure ◽  
Navier Stokes ◽  
Two Phase ◽  
Navier Stokes Equations

scholarly journals Streamlining Fluid Dynamics

1998 ◽  
Vol 120 (03) ◽  
pp. 76-78
Author(s):  
Nathalie Hamill
Keyword(s):  
Fluid Dynamics ◽  
Computer Aided Design ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Tetrahedral Elements ◽  
Starting Point ◽  
Cad Databases ◽  
Computational Fluid Dynamics Cfd ◽  
Aided Design

More-intuitive pre-processors and advanced solvers are making computational fluid dynamics (CFD) software easier to use, more accurate, and faster. CFD techniques involve the solution of the Navier-Stokes equations that describe fluid-flow processes. Using MSC/ PATRAN as a starting point, AEA Technology plc, Harwell, Oxfordshire, England, has developed a pre-processor for its software that is fully computer-aided design (CAD)-compatible and works with native CAD databases such as CADDS 5, CATIA, Euclid3, Pro /ENG INEER, and Unigraphics. The simplicity of modeling complex geometries in CFX allows more details to be included in models, such as gangways between coaches, bogies, and even some parts of the pantograph. CFX 5's coupled solver offers a radically different approach that solves all the hydrodynamic equations as a single system. CFX 5 has demonstrated its ability to deliver much faster pre-processing and shorter run times, thus increasing productivity for its users. CFX 5.2 should be a further step forward in commercial CFD, with its mixed element types combining the accuracy of prismatic meshes adjacent to surfaces with the speed and geometric flexibility of tetrahedral elements in the remainder of the grid.

Computational fluid dynamics prediction of hydrodynamic forces on a manoeuvring ship including effects of dynamic sinkage and trim

2017 ◽  
Vol 233 (1) ◽  
pp. 251-266 ◽  
Author(s):  
Yi Liu ◽  
Lu Zou ◽  
Zao-Jian Zou
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Stokes Equations ◽  
Hydrodynamic Forces ◽  
Numerical Error ◽  
Navier Stokes ◽  
Container Ship ◽  
Navier Stokes Equations ◽  
Sinkage And Trim

Understanding the manoeuvring performance of a ship requires accurate predictions of the hydrodynamic forces and moments on the ship. In the present study, the hydrodynamic forces and moments on a manoeuvring container ship at various rudder and drift angles are numerically predicted by solving the unsteady Reynolds-averaged Navier–Stokes equations. The effects of dynamic sinkage and trim on the hydrodynamic forces are first investigated together with a grid dependency study to estimate the numerical error and uncertainty caused by grid discretization, and with a validation study combining the experimental data. The results show that the effect of dynamic sinkage and trim is non-negligible, since including it improves the hydrodynamic force predictions and reduces the numerical error and uncertainty, and the averaged error and uncertainty are smaller than the other computational fluid dynamics results where sinkage and trim were fixed with given values from model tests. Therefore, it is included in the subsequent systematic simulations regarding the influence of rudder and drift angles. The computed forces, moments and rudder coefficients at different rudder and drift angles on the container ship are compared with the benchmark model test data. From the computations, all the predicted quantities are in satisfactory agreement with the experimental data. The details of the flow filed and hydrodynamic forces, such as pressure distributions, transverse force distributions along the hull, velocity contours, streamlines and wave patterns are presented and discussed, and a deep insight into the physical mechanism in the hydrodynamic forces on a manoeuvring ship is obtained.

scholarly journals A Data Augmentation-Based Technique for Deep Learning Applied to CFD Simulations

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1843
Author(s):  
Alvaro Abucide-Armas ◽  
Koldo Portal-Porras ◽  
Unai Fernandez-Gamiz ◽  
Ekaitz Zulueta ◽  
Adrian Teso-Fz-Betoño
Keyword(s):  
Fluid Dynamics ◽  
Turbulent Flows ◽  
Input Data ◽  
Data Augmentation ◽  
Stokes Equations ◽  
Computational Cost ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Navier Stokes Equations ◽  
Computational Fluid Dynamics Cfd

The computational cost and memory demand required by computational fluid dynamics (CFD) codes simulations can become very high. Therefore, the application of convolutional neural networks (CNN) in this field has been studied owing to its capacity to learn patterns from sets of input data, which can considerably approximate the results of the CFD simulations with relative low errors. DeepCFD code has been taken as a basis and with some slight variations in the parameters of the CNN, while the net is able to solve the Navier–Stokes equations for steady turbulent flows with variable input velocities to the domain. In order to acquire extensive input data to the CNN, a data augmentation technique, which considers the similarity principle for fluid dynamics, is implemented. As a consequence, DeepCFD is able to learn the velocities and pressure fields quite accurately, speeding up the time-consuming CFD simulations.

A viscous blade body force model for computational fluid dynamics–based throughflow analysis of axial compressors

2021 ◽  
pp. 095441002199955
Author(s):  
Jian Li ◽  
Jinfang Teng ◽  
Mingmin Zhu ◽  
Xiaoqing Qiang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Stokes Equations ◽  
Skin Friction Coefficient ◽  
Navier Stokes ◽  
Force Model ◽  
Navier Stokes Equations ◽  
Design Speed ◽  
Airfoil Cascade ◽  
Throughflow Model

In recent years, the computational fluid dynamics (CFD) techniques have attracted enormous interest in the throughflow calculations, and one of the major concerns in the CFD-based throughflow method is the modeling of blade forces. In this article, a viscous blade force model in the CFD-based throughflow program was proposed to account for the loss generation. The throughflow code is based on the axisymmetric Navier–Stokes equations. The inviscid blade force is determined by calculating a pressure difference between the pressure and suction surfaces, and the viscous blade force is related to the local kinetic energy through a skin friction coefficient. The viscous blade force model was validated by a linear controlled diffusion airfoil cascade, and the results showed that it can correctly introduce the loss into the CFD-based throughflow model. Then, the code was applied to calculate the transonic NASA rotor 67, and the calculated results were in good agreement with the measured results, which showed that the calculated shock losses reduce the dependence of the throughflow calculation on the empirical correlation. Last, the 3.5-stage compressor P&W3S1 at 85%, 100%, and 105% of the design speed was performed to demonstrate the reliability of the viscous blade force model in a multistage environment. The results showed that the CFD-based throughflow method can easily predict the spanwise mixing due to the inclusion of the turbulence model, and predicted results were in acceptable agreement with the experimental results. In a word, the proposed viscous blade force model and CFD-based throughflow model can achieve the throughflow analysis with an acceptable level of accuracy and a little time-consuming.

FLUX SPIKES IN VISCOUS FLOWS

2004 ◽  
Vol 14 (01) ◽  
pp. 143-163
Author(s):  
BAI-HE TAN ◽  
ZI-NIU WU
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Stokes Equations ◽  
Viscous Flows ◽  
Navier Stokes ◽  
Navier Stokes Equations

In this paper we will study the condition for the occurrence of flux spikes, such as momentum spikes for the Navier–Stokes equations. Flux spikes are observed in Computational Fluid Dynamics, but it is unknown what are the exact conditions at which they occur and whether they are physical or purely numerical. In the present paper we try to clarify these questions.

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