scholarly journals Numerical Simulation of Internal Loop Reactor for Heavy Oil Slurry Bed Hydroprocessing

2014 ◽  
Vol 7 (1) ◽  
pp. 47-54
Author(s):  
Sun Lanyi ◽  
Wang Jian ◽  
Bai Fei ◽  
Bo Shoushi
Keyword(s):  
Flow Field ◽  
Heavy Oil ◽  
Flow Model ◽  
Scale Up ◽  
Cfd Simulations ◽  
Two Phase ◽  
Loop Reactor ◽  
Internal Loop ◽  
Commercial Code ◽  
Computational Fluid Dynamics Cfd

Computational Fluid Dynamics (CFD) simulations of internal loop reactor for heavy oil slurry bed hydroprocessing have been done in commercial code Fluent 6.3 using Euler two-phase flow model and standard k-ε turbulence model. The effects of the physical properties on the flow field in the reactor are investigated. The results show that the gas density has little effect but the liquid viscosity has a significant effect on flow field and gas hold-up. An analysis of the effect of reactor structures and scale-up on the flow field and gas hold-up are also provided, and optimal structure is obtained through simulations. The conclusions obtained in this paper have great significance for the slurry bed hydrocracking process.

Flow Field Prediction and Bubble Trajectory Model in Gas-Liquid Cylindrical Cyclone (GLCC) Separators

1999 ◽  
Vol 121 (1) ◽  
pp. 9-14 ◽  
Author(s):  
I. Mantilla ◽  
S. A. Shirazi ◽  
O. Shoham
Keyword(s):  
Flow Field ◽  
Flow Model ◽  
Mechanistic Models ◽  
Cfd Simulations ◽  
Trajectory Model ◽  
Swirl Intensity ◽  
Cylindrical Cyclone ◽  
Fluid Properties ◽  
Inlet Geometry ◽  
Computational Fluid Dynamics Cfd

Several mechanistic models have been already developed for predicting the onset of liquid carryover in gas-liquid cylindrical cyclone (GLCC) separators. However, currently no model is available to predict gas carryunder. A bubble trajectory model has been developed that can be used to determine the initiation of gas carryunder in the GLCC and to design GLCC for field applications. The bubble trajectory model uses a predicted flow field in GLCC that is based on swirl intensity. This paper describes the development of a general correlation to predict the decay of the swirl intensity. The correlation accounts for the effects of fluid properties (Reynolds number) as well as inlet geometry. Available experimental data as well as computational fluid dynamics (CFD) simulations were used to validate the correlation. The swirl intensity is used to calculate the local axial and tangential velocities. The flow model and improved bubble trajectory results agree with experimental observation and CFD results. Examples are provided to show how the bubble trajectory model can be used to design GLCC.

Status of Advanced Two-Phase Flow Model Development for SRM Chamber Flow Field and Combustion Modeling

2004 ◽  
Author(s):  
Gary Luke ◽  
Mark Eagar ◽  
Michael Sears ◽  
Scott Felt ◽  
Bob Prozan
Keyword(s):  
Flow Field ◽  
Flow Model ◽  
Two Phase Flow ◽  
Model Development ◽  
Phase Flow ◽  
Two Phase ◽  
Combustion Modeling

Vibratory Finishing of Immobilized Cylinders

2012 ◽  
Vol 565 ◽  
pp. 278-283 ◽  
Author(s):  
Stephen Wan ◽  
Takashi Sato ◽  
Andry Hartawan
Keyword(s):  
Surface Roughness ◽  
Flow Field ◽  
Granular Flow ◽  
Flow Direction ◽  
General Purpose ◽  
Vibratory Finishing ◽  
Cfd Simulations ◽  
Dense Granular Flow ◽  
The Media ◽  
Computational Fluid Dynamics Cfd

We report preliminary results from an on-going study investigating the effect of fixing workpieces within the media flow field contained in a typical vibratory finishing bowl. To this end, we studied the surface roughness evolution over the surfaces of workpieces with generic geometries such as cylinders. A granular flow dynamics model applicable to dense granular flow and a previously derived process equation were invoked in order to respectively describe the flow of the abrasive media; and the roughness distribution in terms of the granular pressure and velocity. By solving the granular flow field for the pressure and velocity distribution on a given geometry using a general purpose computational fluid dynamics (CFD) code, we were able to analyse changes in surface roughness distribution from the process equation. The immobilized cylinders were submerged in the top portion of the media flow field so as to facilitate comparison between media flow past the workpieces as experimentally observed and as predicted by the CFD simulations. We conclude with an analysis, based on both experimental and predicted results, of the way in which media flow direction biases the surface roughness distribution on an immobilized cylinder.

scholarly journals CFD analysis and flow model reduction for surfactant production in helix reactor

2015 ◽  
Vol 21 (1-1) ◽  
pp. 34-44
Author(s):  
N.M. Nikacevic ◽  
L. Thielen ◽  
A. Twerda ◽  
Den Van
Keyword(s):  
Flow Pattern ◽  
Flow Model ◽  
Dispersion Coefficient ◽  
Scale Up ◽  
Three Dimensional ◽  
Response Curves ◽  
Cfd Simulations ◽  
Surfactant Production ◽  
Reactor Application ◽  
Change Response

Flow pattern analysis in a spiral Helix reactor is conducted, for the application in the commercial surfactant production. Step change response curves (SCR) were obtained from numerical tracer experiments by three-dimensional computational fluid dynamics (CFD) simulations. Non-reactive flow is simulated, though viscosity is treated as variable in the direction of flow, as it increases during the reaction. The design and operating parameters (reactor diameter, number of coils and inlet velocity) are varied in CFD simulations, in order to examine the effects on the flow pattern. Given that 3D simulations are not practical for fast computations needed for optimization, scale-up and control, CFD flow model is reduced to one-dimensional axial dispersion (AD) model with spatially variable dispersion coefficient. Dimensionless dispersion coefficient (Pe) is estimated under different conditions and results are analyzed. Finally, correlation which relates Pe number with Reynolds number and number of coils from the reactor entrance is proposed for the particular reactor application and conditions.

Validation of a 2D CFD Model for Hydrodynamics' Studies in CIJ Mixers

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Ricardo J. Santos ◽  
André M. Teixeira ◽  
Ertugrul Erkoç ◽  
Mohamed Sultan ◽  
Anna M Karpinska ◽  
...  
Keyword(s):  
Flow Field ◽  
Impinging Jets ◽  
Cfd Model ◽  
Operational Parameters ◽  
3D Flow ◽  
Cfd Simulations ◽  
Mixing Chamber ◽  
Validity Range ◽  
Computational Fluid Dynamics Cfd ◽  
2D Model

A 2D model of a confined impinging jets mixer having the same geometry of the mixing chamber of a Reaction Injection Moulding, RIM, machine is introduced for the flow field simulation in a Computational Fluid Dynamics, CFD, code. From the CFD simulations the flow field structures and dynamics are clearly established. In addition, the numerical parameters affecting the 2D model simulations are studied, setting for each parameter a validity range. The 2D model is validated and used in the study of some operational parameters: the Reynolds number, the Froude number and the momentum ratio between the opposed jets. The validation of the CFD simulations is also made by comparison with experimental results. The limitations of the 2D model, for simulating the actual 3D flow field, are assessed; from the 2D/3D comparison, it is clearly shown that the introduced model can predict the main flow field features.

Three-Dimensional Numerical Simulation of Fluid with Sparse Particles' Erosion to Pipelines

2013 ◽  
Vol 805-806 ◽  
pp. 1785-1789
Author(s):  
Chang Bin Wang ◽  
Miao Wang ◽  
Xiao Xu Li ◽  
Yu Liu ◽  
Jie Nan Dong
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Flow Model ◽  
Particle Distribution ◽  
Three Dimensional ◽  
Two Phase ◽  
Wear Area ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up ◽  
Volume Method

A three dimensional fluid flow model was set up in this paper, based on the computational fluid dynamics (CFD) and the elasticity theory. Using the finite volume method, a 120° bend was taken as a research object to simulate the erosion to the wall of fluid with sparse particles, finally, to determine the most severe wear areas.At the same time, the distribution of two-phase flows pressure and velocity was analyzed in 45° and 90° bends, then tracked the trajectory of the particles. The results show that the 90°bend has the smallest wear area and particle distribution or combination property is the best.

Analysis of flow field in Si3N4 dry granulation chamber with non-standard composite structure

2020 ◽  
pp. 1-12
Author(s):  
Zhuting Jiang ◽  
Xiang Ning ◽  
Tao Duan ◽  
Nanxing Wu ◽  
Dongling Yu
Keyword(s):  
Flow Field ◽  
Composite Structures ◽  
Flow Model ◽  
Volume Fraction ◽  
Volume Distribution ◽  
Phase Flow ◽  
Two Phase ◽  
Dry Granulation ◽  
Combined Structure ◽  
Internal Distribution

In order to improve the whirling phenomenon of Si3N4 particles in the granulation chamber, the influence of the structure of the granulation chamber on the internal distribution is explored. Euler Euler’s two-phase flow model is established. The flow field in the combined structure granulation chamber with different layout is simulated. The volume distribution and velocity field change of Si3N4 particles in the combined structure granulation chamber with different layout are analyzed. The results show that the angle between two adjacent composite structures is 20∘, 60∘, 80∘ and completely standard the Si3N4 particles with volume fraction index greater than 0.8 account for 10.2%, 11.5%, 12.5% and 6.7% of the total volume respectively. When the combined structure is completely standard, several small convolutions are found. The whirling phenomenon in the granulation chamber is improved. When the angle between two adjacent composite structures is 20∘, 60∘, 80∘ and complete standard, the proportion of qualified particles is 59%, 64%, 66% and 68%. The fluidity index is 84, 85, 87 and 88, respectively. To sum up, the combination structure of the granulation chamber is a complete standard, it is beneficial to improve the spin phenomenon of Si3N4 particles in the granulation chamber.

Quantification of Mixing in RIM Using a Non-Diffusive Two-Phase Flow Numerical Model

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Cláudio P. Fonte ◽  
Ricardo J. Santos ◽  
Madalena M. Dias ◽  
José Carlos B. Lopes
Keyword(s):  
Fluid Dynamics ◽  
Reynolds Number ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Linear Scale ◽  
Cfd Simulations ◽  
Two Phase ◽  
Vof Model ◽  
Mixing Chamber ◽  
Computational Fluid Dynamics Cfd

Mixing in RIM is made mainly by advective mechanisms, rather than diffusion. In this paper, the advective mechanisms that enable reducing the mixing scales down to the values required for the complete chemical reaction of the two monomers inside the RIM mixing chamber are identified and studied. From Computational Fluid Dynamics (CFD) simulations of non-diffusive two-phase flow using the Volume-of-Fluid (VOF) model, a linear scale of segregation is determined as a measure of the degree of mixing and the effect of the Reynolds number is studied.

scholarly journals Modeling Average Pressure and Volume Fraction of a Fluidized Bed Using Data-Driven Smart Proxy

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 123 ◽  
Author(s):  
Ansari ◽  
Mohaghegh ◽  
Shahnam ◽  
Dietiker
Keyword(s):  
Multiphase Flow ◽  
Fluidized Bed ◽  
Volume Fraction ◽  
Scale Up ◽  
Computational Cost ◽  
Cfd Simulations ◽  
Large Numbers ◽  
Computational Fluid Dynamics Cfd ◽  
Using Data ◽  
Artificial Neural Network Ann

Simulations can reduce the time and cost to develop and deploy advanced technologies and enable their rapid scale-up for fossil fuel-based energy systems. However, to ensure their usefulness in practice, the credibility of the simulations needs to be established with uncertainty quantification (UQ) methods. The National Energy Technology Laboratory (NETL) has been applying non-intrusive UQ methodologies to categorize and quantify uncertainties in computational fluid dynamics (CFD) simulations of gas-solid multiphase flows. To reduce the computational cost associated with gas-solid flow simulations required for UQ analysis, techniques commonly used in the area of artificial intelligence (AI) and data mining are used to construct smart proxy models, which can reduce the computational cost of conducting large numbers of multiphase CFD simulations. The feasibility of using AI and machine learning to construct a smart proxy for a gas-solid multiphase flow has been investigated by looking at the flow and particle behavior in a non-reacting rectangular fluidized bed. The NETL’s in house multiphase solver, Multiphase Flow with Interphase eXchanges (MFiX), was used to generate simulation data for the rectangular fluidized bed. The artificial neural network (ANN) was used to construct a CFD smart proxy, which is able to reproduce the CFD results with reasonable error (about 10%). Several blind cases were used to validate this technology. The results show a good agreement with CFD runs while the approach is less computationally expensive. The developed model can be used to generate the time averaged results of any given fluidized bed with the same geometry with different inlet velocity in couple of minutes.

Ablation and Aero-thermodynamic Studies on Thermal Protection Systems of Sharp-Nosed Re-entry Vehicles

2006 ◽  
Vol 129 (7) ◽  
pp. 912-916 ◽  
Author(s):  
S. Rameche Candane ◽  
C. Balaji ◽  
S. P. Venkateshan
Keyword(s):  
Thermodynamic Analysis ◽  
Thermal Protection ◽  
Ablation Rate ◽  
Heat Fluxes ◽  
Zirconium Boride ◽  
Cfd Simulations ◽  
Flow And Heat Transfer ◽  
Commercial Code ◽  
Computational Fluid Dynamics Cfd ◽  
Viscous Compressible Flow

A quasi-one-dimensional ablation analysis for a sharp-nosed, reusable, re-entry vehicle that could possibly be used in an unmanned space program, has been carried out by using an in-house code. The code is based on the boundary immobilization technique and the solution has been obtained using the tri-diagonal matrix algorithm (TDMA). The heat fluxes on the spherical nose cap that are used to determine the ablation rate of a thermal coating applied over the surface of the vehicle are obtained by performing a steady state aero-thermodynamic analysis. The aero-thermodynamic analysis for the viscous, compressible flow under consideration is carried out by using FLUENT 6.2. The computational fluid dynamics (CFD) simulations are performed at three locations on the trajectory that the vehicle follows, on re-entry. These simulations yield the temperature and heat flux distributions along the surface of the vehicle and the latter are given as input to the ablation code. The shell material of the vehicle is assumed to be zirconium boride (ZrB2). The code is validated with benchmark cases and the flow and heat transfer characteristics are also discussed. In brief, the present work presents a methodology for coupling an ablation code with CFD simulations from a commercial code, to study the effect of change of the nose region on the ablation process.

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