Flow pattern velocity and turbulence energy measurements and predictions in a water model of an argon-stirred ladle

1976 ◽  
Vol 7 (2) ◽  
pp. 287-295 ◽  
Author(s):  
J. Szekely ◽  
H. J. Wang ◽  
K. M. Kiser
Keyword(s):  
Flow Pattern ◽  
Water Model ◽  
Turbulence Energy

Investigation of Swirler/Dilution Jet Flow Split on Primary Zone Flow Patterns in a Water Model Can-Type Combustor

1989 ◽  
Vol 111 (2) ◽  
pp. 310-317 ◽  
Author(s):  
P. Koutmos ◽  
J. J. McGuirk
Keyword(s):  
Flow Pattern ◽  
Swirling Flow ◽  
Quantitative Information ◽  
Water Model ◽  
Strong Mixing ◽  
Turbulence Energy ◽  
Mean Velocity ◽  
Primary Zone ◽  
Primary Jets ◽  
Undesirable Feature

LDA measurements of the three mean velocity components and the corresponding turbulence intensities have been made to provide qualitative and quantitative information on the flow field in a water model of a can-type gas turbine combustion chamber. The combustor geometry comprised a swirl-driven primary zone, annulus-fed rows of primary and secondary jets, and an exit contraction. The effect of variation of the flow split between the swirler and the dilution holes on the flow pattern in the primary zone has been investigated in detail. Flow visualization studies revealed that significant changes occur in this region due to the interaction between the swirling flow and the radially directed primary jets. A large toroidal recirculation was formed and high levels of turbulence energy were generated in the core of the combustor at low levels of swirler flow rate. As the swirl level increases, the strength of this recirculation was observed to weaken. Beyond a critical level, the primary recirculation was pushed off center and the undesirable feature of a forward velocity on the combustor axis in the primary zone was observed. Despite the dramatic changes brought about in the primary zone, the flow pattern downstream of the secondary jets was practically the same for all flow splits due to the strong mixing caused by the two rows of jets.

Investigation of Swirler/Dilution Jet Flow Split on Primary Zone Flow Patterns in a Water Model Can-Type Combustor

1985 ◽  
Author(s):  
P. Koutmos ◽  
J. J. McGuirk
Keyword(s):  
Flow Pattern ◽  
Swirling Flow ◽  
Quantitative Information ◽  
Water Model ◽  
Strong Mixing ◽  
Turbulence Energy ◽  
Flow Visualisation ◽  
Mean Velocity ◽  
Primary Zone ◽  
Primary Jets

LDA measurements of the three mean velocity components and the corresponding turbulence intensities have been made to provide qualitative and quantitative information on the flow field in a water model of a can type gas turbine combustion chamber. The combustor geometry comprised a swirl driven primary zone, annulus fed rows of primary and secondary jets and an exit contraction. The effect of variation of the flow split between the swirler and the dilution holes on the flow pattern in the primary zone has been investigated in detail. Flow visualisation studies revealed that significant changes occur in this region due to the interaction between the swirling flow and the radially directed primary jets. A large toroidal recirculation was formed and high levels of turbulence energy generated in the core of the combustor at low levels of swirler flow rate. As the swirl level increases the strength of this recirculation was observed to weaken and become less stable. Beyond a critical level, the primary recirculation was pushed off centre and the undesirable feature of a forward velocity on the combustor axis in the primary zone was observed. Despite the dramatic changes brought about in the primary zone the flow pattern downstream of the secondary jets was practically the same for all flow splits due to the strong mixing caused by the two rows of jets.

Effect of Slag Layer on Flow Patterns in a Gas Stirred Ladle

2006 ◽  
Vol 510-511 ◽  
pp. 490-493 ◽  
Author(s):  
Sung-Ho Cho ◽  
Sung Hwan Hong ◽  
Jeong Whan Han ◽  
Byung Don You
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Model Experiment ◽  
Central Area ◽  
Side Wall ◽  
Slag Layer ◽  
Flow Patterns ◽  
Water Model ◽  
Slag Viscosity ◽  
Mixing Behavior

Flow patterns and mixing behaviors in a gas stirred steelmaking ladle with a slag layer were discussed using a water model experiment as well as a numerical simulation. While the water model experiment was performed to investigate the effect of slag on the mixing behavior in ladle, the numerical simulation was carried out to figure out the flow pattern in ladle with a slag layer. Slag viscosity and its thickness in ladle were considered as major variables. It was found that a slag layer made a great change in the flow pattern in ladle, which, in turn, affected on the mixing behavior in ladle. A flow pattern without a slag layer showed that rising bubbles eventually made a recirculation loop at the central area of the ladle and this flow pattern was regarded as a favorable flow pattern for the better mixing behavior. However, a flow pattern with a slag layer showed distorted and localized recirculating loop near side wall below slag layer. This eventually gave a longer mixing time in ladle with a slag layer. Moreover, as the gas flow rate increases, slag existing on top of the ladle was found to be entrained into the melt. Slag viscosity and its thickness were found to be major variables affecting the behavior of slag entrainment. Lower the slag viscosity and thicker the slag layer, much more slag on top of the melt was entrained into the melt.

Effect of Bottom Structure of Submerged Entry Nozzle on Flow Field in Ultra-Thick Slab Continuous Casting Mold

2010 ◽  
Vol 154-155 ◽  
pp. 840-845 ◽  
Author(s):  
Xin Xie ◽  
Deng Fu Chen ◽  
Qiang Liu ◽  
Jia Long Shen ◽  
Zheng Peng ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Flow Pattern ◽  
Submerged Entry Nozzle ◽  
Casting Process ◽  
Surface Flow ◽  
Water Model ◽  
Continuous Casting Mold ◽  
Flat Bottom ◽  
Thick Slab ◽  
Flow Intensity

Submerged entry nozzle (SEN) bottom structure plays an important role in determining the flow pattern in continuous casting process. This work applies a water model to evaluate the pointed-bottom, flat-bottom and recessed-bottom nozzle performance in ultra-thick slab mold. The jet properties and surface flow are compared for the three kinds of nozzles quantitatively. The results show that flat-bottom and recessed-bottom nozzles are similar in flow pattern, but the pointed-bottom nozzle has smaller jet angle, thinner flow pattern, larger surface asymmetry rate, and higher surface flow intensity.

2D numerical simulation of shallow water and bedload transport in channel confluences by considering the non-hydrostatic pressure

2021 ◽  
Author(s):  
Behnam Balouchi ◽  
Nils Rüther ◽  
Mahmood Shafaei Bejestan ◽  
Kordula Valerie Anne Schwarzwälder ◽  
Hans Bihs
Keyword(s):  
Hydrostatic Pressure ◽  
Shallow Water ◽  
Flow Pattern ◽  
Stokes Equations ◽  
Maximum Velocity ◽  
Bedload Transport ◽  
Water Model ◽  
Effective Parameters ◽  
Complex Flow ◽  
Channel Confluence

<p>Channel confluence is one of the important sections of channel networks which is also common encountered in nature. Six different zones exist at a channel confluence: 1) stagnation zone, 2) flow deflection zone, 3) flow separation zone, 4) maximum velocity zone, 5) flow recovery zone and 6) shear layers between combining flows zone. Due to the complexity of flow pattern at channel confluence, this location is always interesting among researchers. Although there are a number of studies on the flow and sediment pattern at confluences, there are still some gaps to be studied. Hence, a calibrated numerical model should be a good tool for evaluating the various effective parameters on flow and sediment patterns. The numerical 2D shallow-water model used in this paper is SFLOW which was developed by NTNU. Besides, the model calibration part of the current study is done by using a set of data from laboratory experiments.</p><p>This study attempt to simulate bed changes at channel confluences with a 2D shallow-water modeling under non-hydrostatic pressure, and show the applicability of the SFLOW model for this complex flow pattern. SFLOW solving the depth-averaged Navier-Stokes equations which is equipped with cutting-edge solvers. Besides, SFLOW modeled turbulency with depth-averaged two-equation RANS. In comparison with other codes, one of the interesting features of SFLOW is solving the non-hydrostatic pressure besides of hydrostatic part. This leads to a more realistic representation of the complex flow and sediment patterns of channel confluences, and consider less computational power than full 3D models.</p>

Oscillatory Flow in a Physical Model of a Thin Slab Casting Mould With a Bifurcated Submerged Entry Nozzle

2002 ◽  
Vol 124 (2) ◽  
pp. 535-543 ◽  
Author(s):  
Nicholas J. Lawson ◽  
Malcolm R. Davidson
Keyword(s):  
Free Surface ◽  
Flow Visualization ◽  
Flow Pattern ◽  
Oscillatory Flow ◽  
Submerged Entry Nozzle ◽  
High Energy ◽  
Water Model ◽  
Thin Slab ◽  
Thin Slab Casting ◽  
Slab Casting

Laser Doppler anemometry (LDA) measurements are presented of the oscillatory flow in a 33% scale water model of thin slab casting mould when the flow enters as two lateral jets through a bifurcated nozzle. The submerged entry nozzle (SEN) and the mould were geometrically scaled to be representative of industrial thin slab casters. Mean and RMS LDA velocity measurements were taken at three selected points in the region surrounding the SEN, at 500 points in the central plane parallel to the broad face of the mould, and at points in selected transverse sections, for casting rates up to 1.53 m/min. Flow visualization was also taken at two selected planes in the mould. The LDA results showed each jet to form an upper and lower recirculation zone with the lower zones adjacent to one another bounded by the jets and the mould walls and the upper zones bounded by the jet, the SEN, the mould walls and the free surface. Both jets were found to have most oscillatory energy at frequencies below 5 Hz with high energy low frequency modes occurring at frequencies below 0.2 Hz. However, no single dominant frequency occurred in the spectrum and flow visualization revealed an apparently chaotic flow pattern in the oscillation. Midpoint jet deflection was restricted to 6–8 mm RMS, and no coherence was observed between jet (and free surface) movements on either side of the mould. The time averaged flow pattern was found to be almost symmetric across the wide face of the mould. It is concluded that both shear layer instability in the impinging jets, and deflection of the jets due to cross-flow at the SEN-mould wall, contribute to the flow oscillation.

Study of Mold Fluid Flow on a New Type Nozzle Bottom in Continuous Casting of Steel

2011 ◽  
Vol 284-286 ◽  
pp. 1205-1208 ◽  
Author(s):  
Chuan Bo Ji ◽  
Jing She Li ◽  
Xiao Chuan Lin
Keyword(s):  
Continuous Casting ◽  
Flow Pattern ◽  
Water Model ◽  
Velocity Variation ◽  
Mold Surface ◽  
Continuous Casting Of Steel ◽  
Slab Casting ◽  
New Type ◽  
Mold Flow ◽  
The Impact

There are many serious problems are directly associated with the flow pattern in the mold in the continuous casting of steel process. The nozzle flow plays an important role in determining the mold flow pattern and to minimize casting defects. In this work a new type nozzle designed for a slab casting mold is developed. The 3-D steady k-ε finite-volume model has been applied to study the turbulent flow in nozzle and mold, which predict velocities agree with the impeller measurements in the water model well. The results show that nozzles with a mountain bottom are more impressionable to problems from asymmetric flow and large fluctuation on the mold surface. The impact of liquid at wave bottom nozzle can suppress the jet flow effectively and reduce the velocity variation.

Morphology and development of flow-pattern defect with extended nonagitated Secco etching

1994 ◽  
Vol 52 ◽  
pp. 868-869
Author(s):  
Y. Pan
Keyword(s):  
Flow Pattern ◽  
Silicon Crystal ◽  
Gate Oxide ◽  
Crystal Growth Rate ◽  
Etch Depth ◽  
Force Microscopy ◽  
Etch Pit ◽  
Float Zone ◽  
Atomic Force ◽  
Multiple Step

The D defect, which causes the degradation of gate oxide integrities (GOI), can be revealed by Secco etching as flow pattern defect (FPD) in both float zone (FZ) and Czochralski (Cz) silicon crystal or as crystal originated particles (COP) by a multiple-step SC-1 cleaning process. By decreasing the crystal growth rate or high temperature annealing, the FPD density can be reduced, while the D defectsize increased. During the etching, the FPD surface density and etch pit size (FPD #1) increased withthe etch depth, while the wedge shaped contours do not change their positions and curvatures (FIG.l).In this paper, with atomic force microscopy (AFM), a simple model for FPD morphology by non-crystallographic preferential etching, such as Secco etching, was established.One sample wafer (FPD #2) was Secco etched with surface removed by 4 μm (FIG.2). The cross section view shows the FPD has a circular saucer pit and the wedge contours are actually the side surfaces of a terrace structure with very small slopes. Note that the scale in z direction is purposely enhanced in the AFM images. The pit dimensions are listed in TABLE 1.

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