Optimization of Six Strand Tundish Based on Flow and Temperature

2011 ◽  
Vol 239-242 ◽  
pp. 1846-1849
Author(s):  
Sheng Li Li ◽  
Xin Gang Ai ◽  
Dong Wei Zhang ◽  
Nan Lv ◽  
Xiao Dong Hu
Keyword(s):  
Fluid Flow ◽  
Physical Modeling ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Temperature Fields

In this paper the fluid flow and temperature are used together to optimize the 40 tons six strand tundish. Fluid flows in a six strand tundish have been investigated with physical modeling, then steady, three-dimensional temperature fields inside the six strand tundish are obtained. The physical modeling experiments give two optimal integrated tundish structural parameters of baffle holes. From the further study of temperature fields, the tundish should be optimized in the structural parameters of baffle holes in the condition of height 300mm, angel 30° and diameter 20mm.

scholarly journals Modelling bacterial twitching in fluid flows: a CFD-DEM approach

2019 ◽  
Author(s):  
Pahala Gedara Jayathilake ◽  
Bowen Li ◽  
Paolo Zuliani ◽  
Tom Curtis ◽  
Jinju Chen
Keyword(s):  
Fluid Flow ◽  
Shear Flows ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Spherical Particles ◽  
Twitching Motility ◽  
Type Iv ◽  
Computational Fluid Dynamics Cfd ◽  
Dem Model ◽  
Modelling Approach

Bacterial habitats are often associated with fluid flow environments. There is a lack of models of the twitching motility of bacteria in shear flows. In this work, a three-dimensional modelling approach of Computational Fluid Dynamics (CFD) coupled with the Discrete Element Method (DEM) is proposed to study bacterial twitching on flat and groove surfaces under shear flow conditions. Rod-shaped bacteria are modelled as groups of spherical particles and Type IV pili attached to bacteria are modelled as dynamic springs which can elongate, retract, attach and detach. The CFD-DEM model of rod-shape bacteria is validated against orbiting of immotile bacteria in shear flows. The effects of fluid flow rate and surface topography on twitching motility are studied. The model can successfully predict upstream twitching motility of rod-shaped bacteria in shear flows. Our model can predict that there would be an optimal range of wall shear stress in which bacterial upstream twitching is most efficient. The results also indicate that when bacteria twitch on groove surfaces, they are likely to accumulate around the downstream side of the groove walls.

Thermal Convection and Stress Analysis of the Cooling System for a Terahertz Radiation Detector

2015 ◽  
Author(s):  
Angela Wu ◽  
Arturo Pacheco-Vega ◽  
Jeanette Cobian
Keyword(s):  
Fluid Flow ◽  
Laser Irradiation ◽  
Cooling System ◽  
Rectangular Channel ◽  
Radiation Detector ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Stress Strain ◽  
Direct Laser

Detailed three-dimensional numerical simulations have been carried out to find the velocity and temperature fields, in combination with shear and normal stresses, of the fluid flow inside a rectangular channel with large aspect-ratio. The channel under analysis is aimed to cool a thermochromic liquid crystal material (TLC) that is able to capture laser irradiation in the terahertz range. The TLC is manufactured on an extremely-thin substrate. The overall objective of the cooling system is to maintain a nearly-homogeneous temperature of the TLC-domain that is not exposed to the direct laser irradiation, while minimizing the deformation in the TLC caused by the fluid-solid interaction. The fluid flow, stress-strain and heat transfer simulations are carried out on the basis of three-dimensional Navier-Stokes and energy equations for an incompressible flow, coupled with the stress-strain equation for the TLC-layer, to determine values of velocity, pressure and temperature for the fluid inside the channel and the stresses and deformation of the TLC layer, under different operating conditions. These values are then used to find, from a specific set, the value of the channel gap that enables a nearly-uniform temperature distribution in the fluid and the least amount of deformation in the solid layer, within the expected operating conditions. Results from this analysis indicate that, for all the inlet velocities considered, there is a common value of the channel gap, that represents the optimum for the cooling system.

Stator Temperature Distribution of AC Machine Based on Fluid Flow Field

2013 ◽  
Vol 313-314 ◽  
pp. 27-30
Author(s):  
Cong Hui Huang ◽  
Xin Zhen Wu
Keyword(s):  
Fluid Flow ◽  
Flow Field ◽  
Cooling System ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Transfer Coefficients ◽  
Safe Operation ◽  
Heat Transfer Coefficients ◽  
Fluid Field ◽  
Ventilation Ducts

In order to study the impacts of the stator ventilation structure on the thermal performance, the fluid flow model of the stator radial ventilation ducts is established. The fluid flow fields are calculated and analyzed, from which the three-dimensional fluid field distribution inside the radial ventilation ducts is shown. Subsequently, the heat transfer coefficients are obtained on the basis of calculated results of the fluid flow field, and the stator three-dimensional temperature fields are solved. The numerical results are compared among different inlet velocities at the entrance of the radial ventilation ducts, which provides a theory basis for the design of the cooling system and improves the safe operation level of the generator.

Fluid Flow and Heat Transfer Prediction of a Rotating Tapered Inclined Channel

2008 ◽  
Author(s):  
Mehaboob Basha ◽  
Luai M. Al-Hadhrami
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Density Ratio ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Inclined Channel ◽  
Rotation Direction ◽  
Flow And Heat Transfer ◽  
Density Ratios

Fluid flow and heat transfer prediction were conducted to study the three dimensional turbulent flow and heat transfer in rotating tapered inclined channel. Channel orientation is 135° from the rotation direction. Three rotation numbers Ro = 0, 0.1, 0.2 & 0.4 and two inlet coolant-to-wall density ratios 0.1 and 0.40 were investigated, respectively, while keeping Reynolds number constant at 10000. The normalized velocity and temperature fields are presented at two axial locations. The local normalized Nusselt number and spanwise averaged Nusselt number values were reported for three walls; leading, trailing, and top walls. The results show considerable span-wise local Nusselt number variation across the leading, trailing and top walls as the rotation number and density ratio increases.

Numerical Simulation of Fluid Flow in a New High Efficient Mixer

2012 ◽  
Vol 251 ◽  
pp. 226-230
Author(s):  
Qing Wu ◽  
Ya Chen Zhang ◽  
Xue Jun Liu ◽  
Bao An Han
Keyword(s):  
Fluid Flow ◽  
Flow Direction ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Computational Results ◽  
Static Mixer ◽  
Turbulent Model ◽  
Mixing Effect ◽  
High Efficient ◽  
Processing Software

In order to determine proper structural parameters of the new high efficient mixer created by the author, the CFD software is applied to simulate numerically three dimensional incompressible turbulent fields for three static mixing units and the mixing unit with rotating impellor. The static mixing units include three kinds of spiral blades that are single-blade style, three-blade style and four-blade style. Geometric models are built by Pro/ENGINEER and exported to Fluent. The time-mean Reynolds equations and standard turbulent model are applied, and the post-processing software is used to analyze the computational results, and velocity contours and stress contours of mixing fluids in the static mixer will be obtained. The computational results indicate that the direction of outlet velocity of three-blade fluid flow turns more dramatically in comparison with that of single-blade and four-blade fluid flow, and the shearing stress is more remarkable. Because the internal stress of three-blade fluid changes more, the mixing action among fluids is more intensified. All these show three-blade spiral blades have the best mixing effects for local fluids. The rotating impellor mounted between blades can change fluid flow direction and improve the mixing effect for local fluids, which is moved by fluid flow with some velocity.

scholarly journals Modelling bacterial twitching in fluid flows: a CFD-DEM approach

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Pahala Gedara Jayathilake ◽  
Bowen Li ◽  
Paolo Zuliani ◽  
Tom Curtis ◽  
Jinju Chen
Keyword(s):  
Fluid Flow ◽  
Shear Flows ◽  
Bacterial Colonization ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Spherical Particles ◽  
Twitching Motility ◽  
Type Iv ◽  
Computational Fluid Dynamics Cfd ◽  
Surface Patterns

Abstract Bacterial habitats are often associated with fluid flow environments. Bacterial twitching is important for initial bacterial colonization and biofilm formation. The existing research about bacteria twitching is largely experimental orientated. There is a lack of models of twitching motility of bacteria in shear flows, which could provide fundamental understanding about how bacterial twitching would be affected by bacteria associated properties such as number of pili and their distribution on the cell body and environmental factors such as flow and surface patterns. In this work, a three-dimensional modelling approach of Computational Fluid Dynamics (CFD) coupled with the Discrete Element Method (DEM) proposed to study bacterial twitching on flat and groove surfaces under shear flow conditions. Rod-shaped bacteria are modelled as groups of spherical particles and Type IV pili attached to bacteria are modelled as dynamic springs which can elongate, retract, attach and detach. The CFD-DEM model of rod-shape bacteria is validated against orbiting of immotile bacteria in shear flows. The effects of fluid flow rate and surface topography on twitching motility are studied. The model can successfully predict upstream twitching motility of rod-shaped bacteria in shear flows. Our model can predict that there would be an optimal range of wall shear stress in which bacterial upstream twitching is most efficient. The results also indicate that when bacteria twitch on groove surfaces, they are likely to accumulate around the downstream side of the groove walls.

Understanding of the Fluid Flow Mechanism in Porous Media of EOR by ASP Flooding from Physical Modeling

2007 ◽  
Author(s):  
Jialu Wang ◽  
Shiyi Yuan ◽  
Pingping Shen ◽  
Taixian Zhong ◽  
Xu Jia
Keyword(s):  
Porous Media ◽  
Fluid Flow ◽  
Physical Modeling ◽  
Flow Mechanism ◽  
Asp Flooding

Lattice-BGK Methods for Simulating Incompressible Fluid Flows

1997 ◽  
Vol 08 (04) ◽  
pp. 793-803 ◽  
Author(s):  
Yu Chen ◽  
Hirotada Ohashi
Keyword(s):  
Fluid Flow ◽  
Incompressible Fluid ◽  
Poisson Equation ◽  
General Model ◽  
Incompressible Flows ◽  
Fluid Flows ◽  
Incompressible Limit ◽  
Numerical Example ◽  
Incompressible Fluid Flows

The lattice-Bhatnagar-Gross-Krook (BGK) method has been used to simulate fluid flow in the nearly incompressible limit. But for the completely incompressible flows, two special approaches should be applied to the general model, for the steady and unsteady cases, respectively. Introduced by Zou et al.,1 the method for steady incompressible flows will be described briefly in this paper. For the unsteady case, we will show, using a simple numerical example, the need to solve a Poisson equation for pressure.

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