scholarly journals Velocity Control of Visco-Elastic Materials Movement in the Cylindrical Channel of the Grinder Feed Screw of the Former

2019 ◽  
Vol 49 (1) ◽  
pp. 113-119
Author(s):  
Екатерина Фоменко ◽  
Ekaterina Fomenko ◽  
Альберт Нугманов ◽  
Albert Nugmanov
Keyword(s):  
Raw Material ◽  
Navier Stokes ◽  
Surface Model ◽  
Automation System ◽  
Additional Time ◽  
Adhesive Properties ◽  
Navier Stokes Equation ◽  
Feed Screw ◽  
Pass Through ◽  
The One

The present research features the problems of wheat processing. Wheat processing has its own specific features. For instance, the process of gluten extrusion forming is very complex since it is associated with the visco-elastic and adhesive properties of raw gluten. The article discusses the results of applying the numerical finite difference method to the Navier-Stokes equation in the case of the one-dimensional problem when a cooled viscoelastic material has to pass through circular nozzles. The paper also features the obtained surface model of velocity evolution and some averaged results for the possible automation of the process. The viscosity properties of raw gluten are variable and depend on temperature, chemical composition, and properties of the raw material. Modeling makes it possible to characterize the properties of the material and its behavior in various situations. Such research demands neither additional time nor significant costs. The authors identified patterns of movement for raw gluten in the extrusion molding unit and selected the most appropriate automation system to control the speed of its movement to the molding assembly in the grinder feed screw. The significance of the research is obvious for subsequent physical and mathematical modeling of heat and mass transfer processes of vacuum freezing and drying and granulating of gluten extrusions. The results of the research presented in the article are consistent with the available information on this topic. The present approach to solving the problem of choosing the best rational hydrodynamic regimes was applied due to the complexity of the experimental determination of velocity fields and the difficulty of analyzing the Navier-Stokes system of hydrodynamic differential equations with variable proportionality coefficients.

Pumping Speed Measurement of the Rotary Vane Vacuum Pump by Using Numerical and Experimental Approaches

2014 ◽  
Author(s):  
M. Nadeem Azam ◽  
M. Umar ◽  
M. Maqsood ◽  
Imran Akhtar ◽  
Imran Aziz
Keyword(s):  
Internal Flow ◽  
Vacuum Pump ◽  
Assessment System ◽  
Navier Stokes ◽  
Vane Pump ◽  
Navier Stokes Equation ◽  
Time Shape ◽  
Experimental Approaches ◽  
Computational Fluid Dynamics Cfd ◽  
The One

Pumping speed is the main performance parameter of a vacuum pump. In the present work, pumping speed for a three-vane rotary vacuum pump is quantified using both experimental and numerical approaches. The numerical methodology assumes continuum flow (Knudsen number < 0.1), thus allowing the use of Navier Stokes equation. Commercial computational fluid dynamics (CFD) solver i.e. Fluent, is used to discretize the governing equations. Moving / dynamic mesh technique is used for the internal flow volumes of the pump to reproduce the change-in-time shape. Complete process starting from the CAD modeling to CFD simulations is discussed in detail. The adopted approaches are generic and can be used to find the pumping speed of any other rotary vane vacuum pump. The vane pump is also tested using an assessment system, which is constructed according to DIN28432 standard. Results of experimentally measured pumping speed are in good agreement with the one computed numerically.

scholarly journals Simple parametrization methods for generating Adomian polynomials

2016 ◽  
Vol 10 (1) ◽  
pp. 168-185 ◽  
Author(s):  
K.K. Kataria ◽  
P. Vellaisamy
Keyword(s):  
Explicit Expression ◽  
Stokes Equation ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Nonlinear Operators ◽  
Adomian Polynomials ◽  
The One

In this paper, we discuss two simple parametrization methods for calculating Adomian polynomials for several nonlinear operators, which utilize the orthogonality of functions einx, where n is an integer. Some important properties of Adomian polynomials are also discussed and illustrated with examples. These methods require minimum computation, are easy to implement, and are extended to multivariable case also. Examples of different forms of nonlinearity, which includes the one involved in the Navier Stokes equation, is considered. Explicit expression for the n-th order Adomian polynomials are obtained in most of the examples.

The Local Analytic Numerical Method for the Double Vortex Combustor Flow

1985 ◽  
Author(s):  
J. He ◽  
B. Q. Zhang
Keyword(s):  
Reynolds Number ◽  
Analytic Solutions ◽  
Navier Stokes ◽  
Hyperbolic Function ◽  
Navier Stokes Equation ◽  
One Dimensional ◽  
New Type ◽  
High Reynolds ◽  
The One ◽  
Coarse Grids

A new hyperbolic function discretization equation for two dimensional Navier-Stokes equation in the stream function vorticity from is derived. The basic idea of this method is to integrat the total flux of the general variable ϕ in the differential equations, then incorporate the local analytic solutions in hyperbolic function for the one-dimensional linearized transport equation. The hyperbolic discretization (HD) scheme can more accurately represent the conservation and transport properties of the governing equation. The method is tested in a range of Reynolds number (Re=100~2000) using the viscous incompressible flow in a square cavity. It is proved that the HD scheme is stable for moderately high Reynolds number and accurate even for coarse grids. After some proper extension, the method is applied to predict the flow field in a new type combustor with air blast double-vortex and obtained some useful results.

Trackability and Flexibility of Coronary Stents

2010 ◽  
Vol 659 ◽  
pp. 337-342
Author(s):  
Péter Szabadíts ◽  
János Dobránszky
Keyword(s):  
316L Stainless Steel ◽  
Coronary Stents ◽  
Coronary Stent ◽  
Raw Material ◽  
Bending Tests ◽  
Four Point Bending ◽  
Tracking Force ◽  
Pass Through ◽  
The One ◽  
Basic Features

Coronary stents are the most important materials in our days cardiology. Flexibility and trackability are two basic features of stents. In this paper seven different balloon-expandable coronary stent systems were investigated mechanically in order to compare their suitability. The coronary stent systems were assessed by measurements of stent flexibility as well as by comparison of forces during simulated stenting in a self-investigated coronary vessel model. The stents were cut by laser from a single tube of 316L stainless steel or L-605 (CoCr) cobalt chronium alloy. The one- and four point bending tests were carried out to evaluate stent flexibility E∙I (Nmm2), under displacement control in crimped and expanded configurations. The flexibility of stents would rather dependent on the design than raw material. In generally the more flexible stent needs lower tracking force during the implantation. The L-605 row material stents need lower track force to pass through in the vessel model as the 316L row materials stents. In the curve of the vessel model the sort and long stents passed through in different ways. The long stents nestled to the vessel wall at the outer arc and bent, while the short stents did not bend in the curve, only the delivery systems bent.

scholarly journals Direct Numerical Simulation of Gas–Particle Flows with Particle–Wall Collisions Using the Immersed Boundary Method

2018 ◽  
Vol 8 (12) ◽  
pp. 2387 ◽  
Author(s):  
Yusuke Mizuno ◽  
Shun Takahashi ◽  
Kota Fukuda ◽  
Shigeru Obayashi
Keyword(s):  
Immersed Boundary Method ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Navier Stokes ◽  
Immersed Boundary ◽  
Navier Stokes Equation ◽  
Level Set Function ◽  
Boundary Method ◽  
The One ◽  
Energy And Momentum

We investigated particulate flows by coupling simulations of the three-dimensional incompressible Navier–Stokes equation with the immersed boundary method (IBM). The results obtained from the two-way coupled simulation were compared with those of the one-way simulation, which is generally applied for clarifying the particle kinematics in industry. In the present flow simulation, the IBM was solved using a ghost–cell approach and the particles and walls were defined by a level set function. Using proposed algorithms, particle–particle and particle–wall collisions were implemented simply; the subsequent coupling simulations were conducted stably. Additionally, the wake structures of the moving, colliding and rebounding particles were comprehensively compared with previous numerical and experimental results. In simulations of 50, 100, 200 and 500 particles, particle–wall collisions were more frequent in the one–way scheme than in the two-way scheme. This difference was linked to differences in losses in energy and momentum.

scholarly journals Local Exact Controllability for the One-Dimensional Compressible Navier–Stokes Equation

2012 ◽  
Vol 206 (1) ◽  
pp. 189-238 ◽  
Author(s):  
Sylvain Ervedoza ◽  
Olivier Glass ◽  
Sergio Guerrero ◽  
Jean-Pierre Puel
Keyword(s):  
Stokes Equation ◽  
Exact Controllability ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
One Dimensional ◽  
The One

Meta-Modeling Based Optimization of a Directional Augmentation Technique on Improving the Performance of Six Blades Savonius Rotor Using CFD Analysis

2016 ◽  
Author(s):  
Mst Sunzida Ferdoues ◽  
Krishna Vijayaraghavan
Keyword(s):  
Wind Velocity ◽  
Optimization Procedure ◽  
Navier Stokes ◽  
Surface Model ◽  
Navier Stokes Equation ◽  
Convergent Nozzle ◽  
Savonius Rotor ◽  
Meta Modeling ◽  
Computational Fluid Dynamics Cfd ◽  
The Moment

The performance of Savonius wind turbine can be improved by increasing the effective wind velocity. One of the methods of improving the effective wind velocity is using directional augmentation technique, which actually affects the Omnidirectional capability of the Savonius rotor. This paper works on this method by using convergent nozzle at the outlet of the rotor. The whole work is based on Metamodeling based optimization and numerical simulation. Reynolds averaged Navier-stokes equation (RANS) based turbulence model has been used for simulations, such as static simulation and dynamic simulation. The CFD simulations are validated against previously published experimental data. The optimization procedure is performed by integrating the Design of Experiment (DOE), Computational Fluid Dynamics (CFD), Response Surface Model (RSM) and analysis of variance (ANOVA). The meta-model is able to identify significant design variable and the interactions. The proposed optimal nozzle is shown to improve the coefficient of the moment from 0.3 to 0.44.

Wind turbine aerodynamics modeling by meshless method

2020 ◽  
pp. 0309524X2092117
Author(s):  
Asmae Mnebhi-Loudyi ◽  
El Mostapha Boudi ◽  
Driss Ouazar
Keyword(s):  
Finite Difference ◽  
Wind Turbine ◽  
Meshless Method ◽  
Finite Difference Methods ◽  
Navier Stokes ◽  
The Finite Element Method ◽  
Navier Stokes Equation ◽  
Wind Turbine Aerodynamics ◽  
Radial Basis ◽  
The One

This article presents wind turbine aerodynamics modeling by a meshless method. This method does not require meshing but it requires only a set of nodes. The radial basis function of finite difference method is a local meshless method, which is the coupling between the radial basis functions and the finite difference methods. When the number of nodes increases, the system might become ill-conditioned. Therefore, the local meshless method is adopted. It must be noted that Navier–Stokes equation is the one used for modeling purposes. Numerical results were compared to the meshless method and the finite element method results in terms of both velocity and pressure. Close agreements are observed.

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