Numerical and Analytical Investigation of Viscous Fluids in a Screw Extruder

2016 ◽  
Author(s):  
Mustafa Ozsipahi ◽  
Sertac Cadirci ◽  
Hasan Gunes
Keyword(s):  
Analytical Model ◽  
Fluid Transport ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Screw Extruder ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Newtonian Type

This study presents a flow model for a single screw extruder which has been investigated by means of analytical and numerical methods. Flow phenomena in single screw extruders has evoked attention of many researchers since non-Newtonian type of fluid transport by an extruder is utilized in many industrial applications. In this study we focused on the Newtonian-type of fluid transport by a single screw extruder since we aimed to generate an analytical model for the simplified Navier-Stokes equations under certain boundary conditions. The analytical model for a steady, laminar, isothermal and incompressible flow is derived using integral transform technique for a highly viscous flow where the convective acceleration terms are assumed to be negligible. Numerical investigation is conducted by an incompressible, laminar, finite volume based flow solver using a Volume of Fluid (VoF) approximation. An appropriate single-screw extruder model is used for the simulations. The novelty of the study relies on the usage of a simplified analytical model for a highly viscous flow and the comparison between the analytical and numerical results where the numerical results are obtained by a two-phase flow solver for the full Navier-Stokes equations using the complex extruder geometry.

Simulation of the Gap Resonance Between Two Rectangular Barges in Regular Waves by a Free Surface Viscous Flow Solver

2013 ◽  
Author(s):  
B. Elie ◽  
G. Reliquet ◽  
P.-E. Guillerm ◽  
O. Thilleul ◽  
P. Ferrant ◽  
...  
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Viscous Flow ◽  
Stokes Equations ◽  
Resonance Phenomenon ◽  
Navier Stokes ◽  
Regular Waves ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Gap Resonance

This paper compares numerical and experimental results in the study of the resonance phenomenon which appears between two side-by-side fixed barges for different sea-states. Simulations were performed using SWENSE (Spectral Wave Explicit Navier-Stokes Equations) approach and results are compared with experimental data on two fixed barges with different headings and bilges. Numerical results, obtained using the SWENSE approach, are able to predict both the frequency and the magnitude of the RAO functions.

Numerical Solution of Incompressible Unsteady Flows in Turbomachinery

2000 ◽  
Vol 123 (3) ◽  
pp. 680-685 ◽  
Author(s):  
L. He ◽  
K. Sato
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Unsteady Flows ◽  
Navier Stokes ◽  
Time Step ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Time Stepping ◽  
Incompressible Viscous Flow ◽  
Dual Time Stepping

A three-dimensional incompressible viscous flow solver of the thin-layer Navier-Stokes equations was developed for the unsteady turbomachinery flow computations. The solution algorithm for the unsteady flows combines the dual time stepping technique with the artificial compressibility approach for solving the incompressible unsteady flow governing equations. For time accurate calculations, subiterations are introduced by marching the equations in the pseudo-time to fully recover the incompressible continuity equation at each real time step, accelerated with a multi-grid technique. Computations of test cases show satisfactory agreements with corresponding theoretical and experimental results, demonstrating the validity and applicability of the present method to unsteady incompressible turbomachinery flows.

scholarly journals Dynamic Behaviour of the Loads of Podded Propellers in Waves: Experimental and Numerical Simulations

2014 ◽  
Author(s):  
Patrick Queutey ◽  
Jeroen Wackers ◽  
Alban Leroyer ◽  
GanBo Deng ◽  
Emmanuel Guilmineau ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Stokes Equations ◽  
Scale Effects ◽  
Computational Study ◽  
Essential Feature ◽  
Flow Distribution ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Wave Basin

The paper focuses on the hydrodynamic flow around a ship with pods in waves and compares the results of an experimental campaign with numerical simulations conducted during the EU-funded STREAMLINE project. It was the first project for which the effect of waves on cavitation and ventilation was explored in both experimental and numerical ways for a ship with pods. The measurements were carried out in MARIN’s Depressurized Wave Basin (DWB) with a fully instrumented podded ship model, in sailing condition, in waves and depressurised conditions. In this way, the correct representation of cavitation and possible ventilation bubbles and vortices is ensured, resulting in a correct physical behaviour. The discretisation of the Reynolds-Averaged Navier-Stokes Equations (RANSE) is based on the unstructured finite-volume flow solver ISIS-CFD developed by ECN-CNRS. An essential feature for full RANSE simulations with this code is the use of a sliding grid technique to simulate the real propeller rotating behind a ship hull. The computational study in operational service conditions considered here has been conducted to evaluate the instantaneous flow distribution around the podded propellers and to analyse and to compare the unsteady behaviour of the forces induced by the rotating propeller in waves with the measurements from omnidirectional propeller loads as well as the blade forces and moments. The computational study has been done in model and full scale to evaluate the scale effects.

Size-dependent predilections of cardiogenic embolic transport

2013 ◽  
Vol 305 (5) ◽  
pp. H732-H739 ◽  
Author(s):  
Ian A. Carr ◽  
Naohiko Nemoto ◽  
Robert S. Schwartz ◽  
Shawn C. Shadden
Keyword(s):  
Right Hemisphere ◽  
Stokes Equations ◽  
Embolic Stroke ◽  
Navier Stokes ◽  
Human Aorta ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Vertebral Arteries ◽  
Few Data ◽  
Carotid And Vertebral Arteries

While it is intuitively clear that aortic anatomy and embolus size could be important determinants for cardiogenic embolic stroke risk and stroke location, few data exist confirming or characterizing this hypothesis. The objective of this study is to use medical imaging and computational modeling to better understand if aortic anatomy and embolus size influence predilections for cardiogenic embolic transport and right vs. left hemisphere propensity. Anatomically accurate models of the human aorta and branch arteries to the head were reconstructed from computed tomography (CT) angiography of 10 patients. Blood flow was modeled by the Navier-Stokes equations using a well-validated flow solver with physiologic inflow and boundary conditions. Embolic particulate was released from the aortic root and tracked through the common carotid and vertebral arteries for a range of particle sizes. Cardiogenic emboli reaching the carotid and vertebral arteries appeared to have a strong size-destination relationship that varied markedly from expectations based on blood distribution. Observed trends were robust to modeling parameters. A patient's aortic anatomy appeared to significantly influence the probability a cardiogenic particle becomes embolic to the head. Right hemisphere propensity appeared dominant for cardiogenic emboli, which has been confirmed clinically. The predilections discovered through this modeling could represent an important mechanism underlying cardiogenic embolic stroke etiology.

Optimization of a Fan Blade Cascade Using the Parametric Flow Solver Turb’Opty

2006 ◽  
Author(s):  
S. Moreau ◽  
S. Aubert ◽  
G. Grondin ◽  
P. Ferrand
Keyword(s):  
Stokes Equations ◽  
Lift Coefficient ◽  
Taylor Series Expansion ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Free Jet ◽  
Engine Cooling ◽  
Blade Cascade ◽  
Fan Blade

The parameterized CFD solver Turb’Opty™, based on a Taylor series expansion to high order derivatives of the solution of the discretized Navier-Stokes equations, has been successfully applied to the full geometric and flow parameterization of an engine cooling fan blade cascade. The coupling of a recently developed genetic algorithm and the post-processor Turb’Post™ has also yielded a multi-objective optimization of the original Valeo airfoil. A representative geometry of the Pareto front has then been prototyped and tested. Significant improvement of the lift coefficient has been obtained at all incidences. Comparisons with direct Turb’Flow™ cascade results have validated the accuracy of the parameterized solutions and shown the same trend as the free-jet measurements.

Parametric Study of a Turbine Blade Cascade Using a New Parametric Flow Solver Turb’Opty

2002 ◽  
Author(s):  
S. Moreau ◽  
S. Aubert ◽  
M. N’Diaye ◽  
P. Ferrand ◽  
J. Tournier ◽  
...  
Keyword(s):  
Turbine Blade ◽  
Stokes Equations ◽  
Taylor Series Expansion ◽  
Navier Stokes ◽  
Reference Solution ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Blade Cascade ◽  
Polynomial Reconstruction ◽  
Derivatives Of

A new parameterized CFD solver Turb’Opty™ has been developed based on a Taylor series expansion to high order derivatives of the solutions of the discretized Navier-Stokes equations. The method has been successfully applied to the laminar compressible flow field of the T106 turbine blade cascade. Comparisons with the classical CFD results have validated the accuracy of the parameterized solutions obtained by a simple polynomial reconstruction around a reference solution. The CPU efficiency has been emphasized by quickly computing the performance maps (power and losses) of this blade cascade. Wide industrial perspectives of turbomachinery global optimization are finally demonstrated by coupling this method with a simple genetic algorithm.

Parametic Study of a Fan Blade Cascade Using a New Parametric Flow Solver Turb’Opty

2003 ◽  
Author(s):  
S. Moreau ◽  
S. Aubert ◽  
M. N’Diaye ◽  
P. Ferrand
Keyword(s):  
Stokes Equations ◽  
Taylor Series Expansion ◽  
Navier Stokes ◽  
Reference Solution ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Engine Cooling ◽  
Blade Cascade ◽  
Order Expansion ◽  
Fan Blade

The newly developed parameterized CFD solver Turb’Opty™, based on a Taylor series expansion to high order derivatives of the solutions of the discretized Navier-Stokes equations, has been successfully applied to the turbulent incompressible flow field of an engine cooling fan blade cascade. Comparisons with the classical CFD results have validated the accuracy of the parameterized solutions obtained by a simple polynomial reconstruction around a reference solution with respect to two different flow parameters for two different cases: a fifth order expansion with respect to these coupled parameters for a frozen turbulence and a first order expansion with respect to each parameter for a variable turbulence. The latter is found to have a better accuracy and a larger range of application. Starting from a reference solution obtained with another commercial code has also been successfully tested. Finally, further industrial perspectives of turbomachinery global optimization are finally demonstrated by coupling this method with a simple genetic algorithm.

Peristaltic Pumping

2000 ◽  
Author(s):  
M. Tadjfar ◽  
T. Yamaguchi ◽  
R. Himeno
Keyword(s):  
Pressure Wave ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Cylindrical Tube ◽  
Parallel Architecture ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Peristaltic Pumping

Abstract Peristaltic pumping in a cylindrical tube is simulated. The unsteady, three-dimensional, incompressible Navier-Stokes equations are solved numerically. A flow solver written for parallel architecture and capable of dealing with moving boundaries and moving grids is used. The solver uses a second-order in time and third-order upwind finite volume method for solving time-accurate incompressible flows utilizing pseudo-compressibility technique. In this study, the flow of an axisymmetric “Wine-glass” shaped, single, peristaltic wave is analyzed. The wall wave, quickly, establishes a pressure wave in the flow which pumps fluid in the tube as it moves down the tube. The pressure wave, established by the contracting geometric wall wave, grows and diffuses into the upstream and downstream direction in time due to the action of viscosity.

Numerical and scalability analysis of an unstructured Cartesian flow solver

2011 ◽  
Vol 225 (9) ◽  
pp. 2138-2148 ◽  
Author(s):  
Y H Yau ◽  
A Badarudin ◽  
P A Rubini
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Source Codes ◽  
Scalability Analysis ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Parallel Code

This article describes a systematic approach in building a flow solver for large eddy simulation (LES). Finite volume discretizations of the filtered, incompressible, Navier–Stokes equations were explained. The theory progresses to the description of the step-by-step process (mainly in increasing functionality or capability) in developing a three-dimensional, unstructured Cartesian mesh, parallel code after evaluating numerical factors, and available options carried out earlier. This was followed by a presentation of results produced from the simulations of laminar flow, related to the validation of the source codes, which indicates that the flow solver is behaving satisfactorily.

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