scholarly journals Application of Tanks-in-Series Model to Characterize Non-Ideal Flow Regimes in Continuous Casting Tundish

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 208
Author(s):  
Dong-Yuan Sheng ◽  
Zongshu Zou
Keyword(s):  
Model Experiment ◽  
Plug Flow ◽  
Flow Regimes ◽  
Dead Volume ◽  
Water Model ◽  
Flow Volume ◽  
Mixed Flow ◽  
Inclusion Removal ◽  
Ideal Flow ◽  
In Series

This study describes a new tanks-in-series model for analyzing non-ideal flow regimes in a single-strand tundish. The tundish was divided into two interconnected tanks, namely an inlet tank and an outlet tank. A water model experiment was carried out to separately measure the residence-time distribution (RTD) of the two tanks. Drift beads were adopted in the water model experiment to simulate the non-metallic inclusions in molten steel. Dead volume fraction was evaluated by analyzing measured RTD curves. The ratio between mixed flow volume and plug flow volume was proposed as a new criterion to evaluate the inclusion removal. In the inlet tank, a higher mixed flow fraction was preferred to effectively release turbulent kinetic energy and enhance inclusion collision growth. In the outlet tank, a higher plug flow fraction was preferred to facilitate inclusion removal by flotation. The optimal positions of the weir were recommended based on the RTD analysis and the inclusion removal from the results of water model experiments. A theoretical equation was derived based on the tanks-in-series model, providing a good fitting function to analyze the experimental data. The confirmation test was performed by applying computational fluid dynamics simulations of liquid steel flow in the real tundish.

Research on Optimization of Tundish Flow Distrbution

2012 ◽  
Vol 542-543 ◽  
pp. 1132-1138
Author(s):  
Wen Fang Gao ◽  
Jian Jun Zhang ◽  
Zhu Gang Peng ◽  
Wei Li ◽  
Jiang Peng Wu ◽  
...  
Keyword(s):  
Time Distribution ◽  
Flow Behavior ◽  
Plug Flow ◽  
Oxide Inclusion ◽  
Pulse Response ◽  
Dead Volume ◽  
Water Model ◽  
Control Solution ◽  
Minimum Residence Time ◽  
Turbulence Inhibitor

Research was made on the flow behavior of the 45t single strand tundish by means of water model. The model was 1:3 in size of the real tundish. Experiment conditions satisfied Froude number similarity. Minimum residence time distribution (RTD) curves were determined by pulse response. The proportion of the plug flow, mixed flow and dead volume were calculated. An optimized solution was made of a combination of turbulence inhibitor, dam and weir to decrease the dead volume (Vd) in the tundish to 11.36%, 67.8% lower than before. Production contrast tests showed that, with the optimized flow control solution, removal of oxide inclusion in slab is improved by 35.3%.

scholarly journals Integrated impedance sensing of liquid sample plug flow enables automated high throughput NMR spectroscopy

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Omar Nassar ◽  
Mazin Jouda ◽  
Michael Rapp ◽  
Dario Mager ◽  
Jan G. Korvink ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
High Throughput ◽  
Plug Flow ◽  
Microfluidic System ◽  
High Resolution Spectroscopy ◽  
Dead Volume ◽  
Absolute Difference ◽  
Immiscible Fluid ◽  
Flow Sensors ◽  
Novel Approach

AbstractA novel approach for automated high throughput NMR spectroscopy with improved mass-sensitivity is accomplished by integrating microfluidic technologies and micro-NMR resonators. A flow system is utilized to transport a sample of interest from outside the NMR magnet through the NMR detector, circumventing the relatively vast dead volume in the supplying tube by loading a series of individual sample plugs separated by an immiscible fluid. This dual-phase flow demands a real-time robust sensing system to track the sample position and velocities and synchronize the NMR acquisition. In this contribution, we describe an NMR probe head that possesses a microfluidic system featuring: (i) a micro saddle coil for NMR spectroscopy and (ii) a pair of interdigitated capacitive sensors flanking the NMR detector for continuous position and velocity monitoring of the plugs with respect to the NMR detector. The system was successfully tested for automating flow-based measurement in a 500 MHz NMR system, enabling high resolution spectroscopy and NMR sensitivity of 2.18 nmol s1/2 with the flow sensors in operation. The flow sensors featured sensitivity to an absolute difference of 0.2 in relative permittivity, enabling distinction between most common solvents. It was demonstrated that a fully automated NMR measurement of nine individual 120 μL samples could be done within 3.6 min or effectively 15.3 s per sample.

scholarly journals A numerical study of glacier advance over deforming till

2010 ◽  
Vol 4 (3) ◽  
pp. 359-372 ◽  
Author(s):  
G. J.-M. C. Leysinger Vieli ◽  
G. H. Gudmundsson
Keyword(s):  
Effective Viscosity ◽  
Numerical Study ◽  
Thickness Distribution ◽  
Plug Flow ◽  
Linear Wave ◽  
Sediment Layer ◽  
Mixed Flow ◽  
Model Experiments ◽  
Non Linear ◽  
Glacier Advance

Abstract. The advance of a glacier over a deforming sediment layer is analysed numerically. We treat this problem as a contact problem involving two slowly-deforming viscous bodies. The surface evolution of the two bodies, and of the contact interface between them, is followed through time. Using various different non-linear till rheologies, we show how the mode of advance depends on the relative effective viscosities of ice and till. Three modes of advances are observed: (1) overriding, where the glacier advances through ice deformation only and without deforming the sediment; (2) plug-flow, where the sediment is strongly deformed, the ice moves forward as a block and a bulge is built in front of the glacier; and (3) mixed-flow, where the glacier advances through both ice and sediment deformation. For the cases of both overriding and mixed-flow, an inverse depth-age relationship within the ice is obtained. A series of model experiments show the contrast in effective viscosity between ice and till to be the single most important model parameter defining the mode of advance and the resulting thickness distribution of the till. Our model experiments indicate that the thickness of the deforming till layer is greatest close to the glacier front. Measurements of till thickness taken in such locations may not be representative of deforming till thickness elsewhere. Given sufficiently large contrast in effective viscosity between ice and till, a sediment bulge is formed in front of the glacier. During glacier advance, the bulge quickly reaches a steady state form strongly resembling single-crested push moraines. Inspection of particle paths within the sediment bulge, shows that particles within the till travel at a different speed from the bulge itself, and the push moraine to advance as a form-conserving non-linear wave.

Urban Traffic Flow Volume Modeling for Beijing Using a Mixed-Flow Model

2008 ◽  
Vol 8 (3) ◽  
pp. 111-114 ◽  
Author(s):  
Zhiheng LI ◽  
Shengchao YIN ◽  
Ye TIAN ◽  
Li LI ◽  
Zhiqiang ZHAO ◽  
...  
Keyword(s):  
Traffic Flow ◽  
Flow Model ◽  
Urban Traffic ◽  
Flow Volume ◽  
Mixed Flow ◽  
Volume Modeling

The Model Analysis of Inclusion Moving in the Swirl Flow Zone Sourcing from the Inner-Swirl-Type Turbulence Controller in Tundish

2017 ◽  
Vol 36 (5) ◽  
pp. 541-550 ◽  
Author(s):  
Yan Jin ◽  
Chen Ye ◽  
Xiao Luo ◽  
Hui Yuan ◽  
Changgui Cheng
Keyword(s):  
Flow Field ◽  
Swirling Flow ◽  
Mathematic Model ◽  
Swirl Flow ◽  
Water Model ◽  
Medium Size ◽  
Force Analysis ◽  
Inclusion Removal ◽  
Flow Band ◽  
Turbulence Inhibitor

AbstractIn order to improve the inclusion removal property of the tundish, the mathematic model for simulation of the flow field sourced from inner-swirl-type turbulence controller (ISTTC) was developed, in which there were six blades arranged with an eccentric angle (θ) counterclockwise. Based on the mathematical and water model, the effect of inclusion removal in the swirling flow field formed by ISTTC was analyzed. It was found that ISTTC had got the better effect of inhibiting turbulence in tundish than traditional turbulence inhibitor (TI). As the blades eccentric angle (θ) of ISTTC increasing, the intensity of swirling flow above it increased. The maximum rotate speed of fluid in swirling flow band driven by ISTTC (θ=45°) was equal to 25 rmp. Based on the force analysis of inclusion in swirling flow sourced from ISTTC, the removal effect of medium size inclusion by ISTTC was attributed to the centripetal force (Fct) of swirling flow, but removal effect of ISTTC to small size inclusion was more depend on its better turbulence depression behavior.

Reactor Design for Complex Reactions

2001 ◽  
Author(s):  
L. K. Doraiswamy
Keyword(s):  
Batch Reactor ◽  
Plug Flow ◽  
Reaction Network ◽  
Reactor Design ◽  
Batch Reactors ◽  
Complex Reaction ◽  
Mixed Flow ◽  
Flow Reactors ◽  
Design Procedures ◽  
Reactor Types

Procedures were formulated in Chapter 5 for treating complex reactions. We now turn to the design of reactors for such reactions. Continuing with the ethylation reaction, we consider the following reactor types for which design procedures were formulated earlier in Chapter 4 for simple reactions: batch reactors, continuous stirred reactors (or mixed-flow reactors), and plug-flow reactors. However, we use the following less formal nomenclature: A = aniline, B = ethanol, C = monoethyaniline, D = water, E = diethylaniline, F = diethyl ether, and G = ethylene. The four independent reactions then become Using this set of equations as the basis, we now formulate design equations for various reactor types. Detailed expositions of the theory are presented in a number of books, in particular Aris (1965, 1969) and Nauman (1987). Consider a reaction network consisting of N components and M reactions. A set of N ordinary differential equations, one for each component, would be necessary to mathematically describe this system. They may be concisely expressed in the form of Equation 5.5 (Chapter 5), or . . . d(cV)/dt = vrV (11.1) . . . The use of this equation in developing batch reactor equations for a typical complex reaction is illustrated in Example 11.1.

scholarly journals Silicon microfabricated reactor for operando XAS/DRIFTS studies of heterogeneous catalytic reactions

2020 ◽  
Vol 10 (23) ◽  
pp. 7842-7856 ◽  
Author(s):  
B. Venezia ◽  
E. Cao ◽  
S. K. Matam ◽  
C. Waldron ◽  
G. Cibin ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Plug Flow ◽  
Catalytic Reactions ◽  
Dead Volume ◽  
Heterogeneous Catalytic ◽  
Spatially Resolved ◽  
Operando Xas

A novel microreactor for operando XAS and DRIFTS studies of catalytic reactions is reported, exhibiting plug-flow, isothermal behaviour and absence of mass transfer resistances and dead volume, enabling time- and spatially-resolved experiments.

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