scholarly journals Three-Dimensional CFD Simulation of Fluid Flow inside a Vortex Tube on Basis of an Experimental Model- The Optimization of Vortex Chamber Radius

2016 ◽  
Vol 34 (2) ◽  
pp. 236-244 ◽  
Author(s):  
S. Rafiee ◽  
M. Sadeghiazad
Keyword(s):  
Fluid Flow ◽  
Experimental Model ◽  
Cfd Simulation ◽  
Vortex Tube ◽  
Three Dimensional ◽  
Vortex Chamber

Comparison of CFD Simulation to the Experiments for Forward Step Flows

2003 ◽  
Author(s):  
Shoichiro Nakamura ◽  
Hiroyuki Onuma ◽  
Peter G. Carswell
Keyword(s):  
Fluid Flow ◽  
Vortex Shedding ◽  
Cfd Simulation ◽  
Computational Simulation ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Unsteady Motion ◽  
Computational Results ◽  
Over The Top ◽  
Unsteady Behavior

Three dimensional DNS simulation on the fluid flow over a forward step configuration are compared with the experiments reported by Shakouchi, Ando, and Ito. This is a part of authors’ attempts to evaluate the validity of three dimensional unsteady flow simulation by comparison to experiments. Summary of the comparison is as follows: (1) vortex shedding in the flow separation over the top of the step near the corner is observed, (2) frequency of vortex shedding and distance between two consecutive vortices do not agree with the experiment, (3) however, while steady periodic shedding of vortices from the top corner of the step is reported for the experimental results, the computational results show unsteady behavior of the flow over the top corner, which results in unsteady shedding of vortices. This unsteadiness in the computational simulation is due to unsteady motion of fluid upstream from the step where adverse pressure increase occurs.

Determination of Outside Heating Distribution Using an Inverse Algorithm for an Industry Hydrothermal Autoclave With Three-Dimensional Flows

2004 ◽  
Author(s):  
Hongmin Li ◽  
Minel J. Braun ◽  
G.-X. Wang ◽  
Edward A. Evans
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Fluid Flow ◽  
Heat Conduction ◽  
Flux Distribution ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Heat Flux Distribution ◽  
Inverse Algorithm ◽  
Small Magnitude

Hydrothermal growth is the industry method of preference to obtain high quality single crystals. Due to the high pressure and high temperature growth conditions, growth process is carried out in closed containers. During a growth run, the only flow and heat transfer that control crystal growers have is the outside heating. An inverse algorithm, used to obtain the heating distribution for an autoclave with a two-dimensional flow, is further developed and used to determine the heating distribution for an industry autoclave with three-dimensional flows. A cross-section area average temperature distribution is set as a target. With the three steps, including CFD simulation of the fluid flow, heat conduction in the metal wall, and heat conduction in the insulation layer, the heater heat flux distribution is determined. The distributions appear close to linear from the median height to the top/bottom with small magnitude deviation in the circumferential direction. Linearly distributed heaters, based on the determined heat flux distribution, are then used and heat transfer and fluid flow is numerically simulated with a conjugate model. The achieved temperature agrees well with the targeted one. The distribution and heating rates of linearly distributed heaters can be applied to industry autoclaves.

scholarly journals CFD Simulation of Aeration and Mixing Processes in a Full-Scale Oxidation Ditch

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1633 ◽  
Author(s):  
Thomas Höhne ◽  
Tural Mamedov
Keyword(s):  
Fluid Flow ◽  
Cfd Simulation ◽  
Pure Water ◽  
Three Dimensional ◽  
Continuous Phase ◽  
Full Scale ◽  
Solid Particles ◽  
Mixing Processes ◽  
Treatment Processes ◽  
Sst Turbulence Model

This study aims to build a computational fluid dynamics (CFD) model that can be used to predict fluid flow pattern and to analyse the mixing process in a full-scale OD. CFD is a widely used numerical tool for analysing, modelling and simulating fluid flow patterns in wastewater treatment processes. In this study, a three-dimensional (3D) computational geometry was used, and the Eulerian-Eulerian multiphase flow model was built. Pure water was considered as the continuous phase, whereas air was modelled as the dispersed phase. The Shear Stress Transport (SST) turbulence model was specified which predicts turbulence eddies in free stream and wall-bounded region with high accuracy. The momentum source term approach and the transient rotor-stator approach were implemented for the modelling of the submersible agitators. The hydrodynamic analysis was successfully performed for four different scenarios. In order to prevent the incorrect positioning of the submerged agitators, thrust analysis was also done. The results show that the minimum required water velocity was reached to maintain the solid particles suspended in the liquid media and adequate mixing was determined.

scholarly journals CFD analysis of helical nozzles effects on the energy separation in a vortex tube

2012 ◽  
Vol 16 (1) ◽  
pp. 151-166 ◽  
Author(s):  
Nader Pourmahmoud ◽  
Hassan Zadeh ◽  
Omid Moutaby ◽  
Abdolreza Bramo
Keyword(s):  
Vortex Tube ◽  
Numerical Models ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Vortex Chamber ◽  
Energy Separation ◽  
Outlet Temperature ◽  
Computational Domain ◽  
Cfd Analysis ◽  
Swirl Velocity

In this article computational fluid dynamics (CFD) analysis of a three-dimensional steady state compressible and turbulent flow has been carried out through a vortex tube. The numerical models use the k-? turbulence model to simulate an axisymmetric computational domain along with periodic boundary conditions. The present research has focused on the energy separation and flow field behavior of a vortex tube by utilizing both straight and helical nozzles. Three kinds of nozzles set include of 3 and 6 straight and 3 helical nozzles have been investigated and their principal effects as cold temperature difference was compared. The studied vortex tubes dimensions are kept the same for all models. The numerical values of hot and cold outlet temperature differences indicate the considerable operating role of helical nozzles, even a few numbers of that in comparing with straight nozzles. The results showed that this type of nozzles causes to form higher swirl velocity in the vortex chamber than the straight one. To be presented numerical results in this paper are validated by both available experimental data and flow characteristics such as stagnation point situation and the location of maximum wall temperature as two important facts. These comparisons showed reasonable agreement.

Transient DEM-CFD simulation of solid and fluid flow in a three dimensional blast furnace model

2018 ◽  
Vol 334 ◽  
pp. 53-64 ◽  
Author(s):  
F. Bambauer ◽  
S. Wirtz ◽  
V. Scherer ◽  
H. Bartusch
Keyword(s):  
Blast Furnace ◽  
Fluid Flow ◽  
Cfd Simulation ◽  
Three Dimensional

scholarly journals Numerical Study toward Optimization of Spray Drying in a Novel Radial Multizone Dryer

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1233
Author(s):  
Umair Jamil Ur Rahman ◽  
Artur Krzysztof Pozarlik ◽  
Thomas Tourneur ◽  
Axel de Broqueville ◽  
Juray De Wilde ◽  
...  
Keyword(s):  
Spray Drying ◽  
Droplet Size ◽  
Separation Efficiency ◽  
Numerical Study ◽  
Three Dimensional ◽  
Droplet Size Distribution ◽  
Vortex Chamber ◽  
Temperature Pattern ◽  
Multiphase Model ◽  
Drying Technology

In this paper, an intensified spray-drying process in a novel Radial Multizone Dryer (RMD) is analyzed by means of CFD. A three-dimensional Eulerian–Lagrangian multiphase model is applied to investigate the effect of solids outlet location, relative hot/cold airflow ratio, and droplet size on heat and mass transfer characteristics, G-acceleration, residence time, and separation efficiency of the product. The results indicate that the temperature pattern in the dryer is dependent on the solids outlet location. A stable, symmetric spray behavior with maximum evaporation in the hot zone is observed when the solids outlet is placed at the periphery of the vortex chamber. The maximum product separation efficiency (85 wt %) is obtained by applying high G-acceleration (at relative hot/cold ratio of 0.75) and narrow droplet size distribution (45–70 µm). The separation of different sized particles with distinct drying times is also observed. Smaller particles (<32 µm) leave the reactor via the gas outlet, while the majority of big particles leave it via the solids outlet, thus depicting in situ particle separation. The results revealed the feasibility and benefits of a multizone drying operation and that the RMD can be an attractive solution for spray drying technology.

scholarly journals A Three-Dimensional Numerical and Multi-Objective Optimal Design of Wavy Plate-Fins Heat Exchangers

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Chao Yu ◽  
Xiangyao Xue ◽  
Kui Shi ◽  
Mingzhen Shao
Keyword(s):  
Heat Exchangers ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Basis Functions ◽  
Approximation Model ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Multi Objective Genetic Algorithm ◽  
Colburn Factor ◽  
Heat Exchange Efficiency

This paper presents a method for optimizing wavy plate-fin heat exchangers accurately and efficiently. It combines CFD simulation, Radical Basis Functions (RBF) with multi-objective optimization to improve the performance. The optimization of the Colburn factor j and the friction coefficient f is regarded as a multi-objective optimization problem, due to the existence of two contradictory goals. The approximation model was obtained by Radical Basis Functions, and the shape of the heat exchanger was optimized by multi-objective genetic algorithm (MOGA). The optimization results showed that j increased by 17.62% and f decreased by 20.76%, indicating that the heat exchange efficiency was significantly enhanced and the fluid structure resistance reduced. Then, from the aspects of field synergy and tubulence energy, the performance advantage of the optimized structure was further confirmed.

scholarly journals Fast multipole solvers for three-dimensional radiation and fluid flow problems

1999 ◽  
Vol 7 ◽  
pp. 408-417 ◽  
Author(s):  
J. H. Strickland ◽  
L. A. Gritzo ◽  
R. S. Baty ◽  
G. F. Homicz ◽  
S. P. Burns
Keyword(s):  
Fluid Flow ◽  
Three Dimensional ◽  
Fast Multipole ◽  
Flow Problems

Three-dimensional CFD simulation of anaerobic reactions in a continuous packed-bed bioreactor

2021 ◽  
Author(s):  
Sasan Zarei ◽  
Seyyed Mohammad Mousavi ◽  
Teimour Amani ◽  
Mehrdad Khamforoush ◽  
Arezou Jafari
Keyword(s):  
Cfd Simulation ◽  
Three Dimensional ◽  
Packed Bed ◽  
Packed Bed Bioreactor
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