scholarly journals Numerical Study of Turbulent Flows and Heat Transfer in Coupled Industrial-Scale Tundish of a Continuous Casting Material in Steel Production

2018 ◽  
Author(s):  
Jose Adilson de Castro ◽  
Bruno Amaral Pereira ◽  
Roan Sampaio de Souza ◽  
Elizabeth Mendes de Oliveira ◽  
Ivaldo Leão Ferreira
Keyword(s):  
Heat Transfer ◽  
Continuous Casting ◽  
Turbulent Flows ◽  
Numerical Study ◽  
Steel Production ◽  
Industrial Scale

Steel Structure Prediction for Continuous Steel Casting by Means of a Parallel GPU-Based Heat Transfer and Solidification Model

2015 ◽  
Author(s):  
Lubomír Klimeš ◽  
Josef Štětina ◽  
Tomáš Mauder
Keyword(s):  
Heat Transfer ◽  
Continuous Casting ◽  
Structure Prediction ◽  
Steel Production ◽  
Steel Structure ◽  
Production Method ◽  
Micro Structure ◽  
Solidification Model ◽  
Minimum Number ◽  
Heat Transfer And Solidification

Continuous casting of steel is currently a predominant production method of steel, which is used for more than 95% of the total world steel production. An effort of steelmakers is to cast high-quality steel with a desired structure and with a minimum number of defects, which reduce the productivity. The paper presents our developed GPU-based heat transfer and solidification model for continuous casting, which is coupled with a submodel used for the prediction of the steel micro-structure. The model is implemented in CUDA/C++, which allows for rapid computing on NVIDIA GPUs. The time-dependent temperature distribution calculated by the thermal model is iteratively passed to the submodel for the steel micro-structure prediction. The structural submodel determines the spatially-dependent rates of temperature change in the strand, for which the interdendritic solidification model IDS predicts the micro-structure of steel. The paper presents preliminary simulation results for the steel grade used for pressure vessel plates, which is sensitive to rapid cooling rates.

Effect of a Pair of Horizontal Frame Members on the Convective Heat Transfer With Laminar and Turbulent Flow From a Recessed Window to a Room

2011 ◽  
Author(s):  
Patrick H. Oosthuizen ◽  
David Naylor
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Convective Heat Transfer ◽  
Turbulent Flows ◽  
Heat Transfer Rate ◽  
Convective Heat ◽  
Transfer Rate ◽  
Numerical Study ◽  
Wall Functions ◽  
Inner Surface

The horizontal frame members that often protrude from the inner surface of a window can significantly effect the convective heat transfer rate from this inner surface to the room. The purpose of the present numerical study was to determine how the size of a pair of horizontal frame members effect this heat transfer rate. The flow has been assumed to be steady and conditions under which laminar, transitional, and turbulent flows occur are considered. Fluid properties have been assumed constant except for the density change with temperature that gives rise to the buoyancy forces, this being dealt with using the Boussinesq approach. The governing equations have been solved using the FLUENT commercial CFD code. The k-epsilon turbulence model with standard wall functions and with buoyancy force effects fully accounted for has been used. The solution has the following parameters: the Rayleigh number, the Prandtl number, the dimensionless window recess depth, and the dimensionless width and depth of the frame members. Results have been obtained for a Prandtl number of 0.74.

Numerical Study of Heat Transfer in Turbulent Cross-Flow Over Porous-Coated Cylinder

2017 ◽  
Author(s):  
N. Rahmati ◽  
Z. Mansoori ◽  
M. Saffar-Avval ◽  
G. Ahmadi
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Nusselt Number ◽  
Turbulent Flows ◽  
Metal Foam ◽  
Numerical Study ◽  
Flow Analysis ◽  
Cross Flow ◽  
Local Thermal Equilibrium ◽  
Turbulent Regime

In the present paper, a numerical study has been conducted to investigate the heat transfer from a constant temperature cylinder covered with metal foam. The cylinder is placed horizontally and is subjected to a constant mean cross-flow in turbulent regime. The Reynolds Averaged Navier-Stokes (RANS) and Darcy-Brinkman-Forchheimer equations are combined and used for flow analysis. The energy equation used assumes local thermal equilibrium between fluid and solid phases in porous media. The k-ω SST turbulence model is used to evaluate the eddy viscosity that is implemented in the momentum and energy equations. The flow in the metal foam (porous media) is in laminar regime. Governing equations are solved using the finite volume SIMPLEC algorithm. The effect of thermophysical properties of metal foam such as porosity and permeability on the Nusselt number is investigated. The results showed that using a metal porous layer with low porosity and high Darcy number in high Reynolds number turbulent flows markedly increases heat transfer rates. The corresponding increase in the Nusselt number is as high as 10 times that of a bare tube without the metal foam.

Large Eddy Simulation of Heat Transfer Over In-Line Flat-Tube Array in Laminar and Turbulent Flows

2017 ◽  
Author(s):  
Salar Taghizadeh ◽  
Sumanta Acharya ◽  
Kong Ling ◽  
Yousef Kanani ◽  
Xuan Ge
Keyword(s):  
Heat Transfer ◽  
Large Eddy Simulation ◽  
Turbulent Flows ◽  
Numerical Study ◽  
Numerical Models ◽  
Leading Edge ◽  
Flat Tube ◽  
Eddy Simulation ◽  
Wide Range ◽  
Large Eddy

This study presents a transient three-dimensional numerical study on fluid flow and heat transfer of flat-tube array using large eddy simulation (LES) covering both laminar and turbulent flow regimes. The simulations were performed in a rectangular region containing only one tube with periodic conditions specified on all boundaries. A staggered flat-plate array was first studied, and an existing solution was used for validation purpose. The numerical models were then applied to an in-line array composed of flat tubes with an aspect ratio of 0.25 and fixed tube spacings. By varying the in-flow velocity, the tube array was studied over a wide range of Reynolds number (600–12000). Temperature, velocity, and turbulent kinetic energy distributions as well as the interactions between them are presented and analyzed. Furthermore, the local heat transfer rate was analyzed along the various parts of the tube (leading edge, flat-top and wake or trailing-edge regions). Heat transfer correlation for each region of the tube and the entire tube array is proposed.

scholarly journals Design of a radiative heat recuperator for steel processes

2020 ◽  
Vol 330 ◽  
pp. 01034
Author(s):  
Peru Fernandez Arroiabe ◽  
Jon Iturralde Iñarga ◽  
Mercedes Gómez de Arteche Botas ◽  
Susana López Pérez ◽  
Eduardo Ubieta Astigarraga ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Waste Heat ◽  
Numerical Study ◽  
Steel Production ◽  
Flow Distribution ◽  
Radiative Energy ◽  
Production Plant ◽  
Heat Recuperator

In recent years, there has been an increasing interest in the recovery of the waste heat of steel and glass processes. This work proposes a numerical study of a waste heat exchanger system for steel production processes. The radiative energy is transferred to a commercial oil, which can be used to produce electricity. The behavior of the recuperator is analysed using a 3D numerical model, considering the constrains of a real production plant. The influence of the radiation properties of the materials on the temperature and heat transfer rate are also examined. The results show that the absorptivity of the tubes influences significantly the absorbed waste heat. Furthermore, heterogeneous mass flow distribution should be applied to optimize the total heat transfer rate.

scholarly journals Numerical Study of Turbulent Flows and Convective Heat Transfer of Al2O3-Water Nanofluids In A Circular Tube

2020 ◽  
Vol 77 (2) ◽  
pp. 1-12
Author(s):  
Abdelkader Mahammedi ◽  
Houari Ameur ◽  
Younes Menni ◽  
Driss Meddah Medjahed
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Convective Heat Transfer ◽  
Turbulent Flows ◽  
Convective Heat ◽  
Circular Tube ◽  
Numerical Study ◽  
Constant Heat Flux ◽  
Flux Boundary Condition ◽  
Pressure Losses

The convective heat transfer of Al2O3-water nanofluids through a circular tube with a constant heat flux boundary condition is studied numerically. Turbulent flow conditions are considered with a Reynolds number ranging from 3500 to 20000. The numerical method used is based on the single-phase model. Four volume concentrations of Al2O3-water nanoparticles (0.1, 0.5, 1, and 2%) are used with a diameter of nanoparticle of 40 nm. A considerable increase in Nusselt number, axial velocity, and turbulent kinetic energy was found with increasing Reynolds number and volume fractions. However, the pressure losses were also increased with the raise of Re and nanoparticles concentration.

scholarly journals The Peculiarities of Convective Heat Transfer in Melt of a Multiple-Electrode Arc Furnace

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1174
Author(s):  
Alexsey Kukharev ◽  
Vyacheslav Bilousov ◽  
Ecaterina Bilousov ◽  
Vitaly Bondarenko
Keyword(s):  
Heat Transfer ◽  
Eddy Currents ◽  
Numerical Study ◽  
Structural Parameters ◽  
Low Frequency ◽  
Steel Production ◽  
Nonuniform Heating ◽  
Melt Mixing ◽  
Thermogravitational Convection ◽  
Arc Furnaces

The modern direction of improving the technology of steel production in high-power arc furnaces is the intensification of magnetohydrodynamic effects for mixing the melt. In this article, a furnace design is proposed that contains three roof arc and three bottom electrodes, which provides the formation of additional eddy currents in the melt when the furnace is supplied with direct current or a low-frequency current. For a numerical study of the features of heat transfer in the melt of this furnace, a three-dimensional mathematical model of magnetohydrodynamic and thermal processes was used. The results were processed using the methods of visualization of vortex structures and the Richardson criterion. In an oven with a capacity of 180 tons at currents in the electrodes of 80 kA, the conditions for the interaction of electric vortex and thermogravitational convection were studied. Results showed that thermogravitational convection due to nonuniform heating of the melt led to a decrease in the size of the main electric vortex flow and the formation of an additional flow near the side walls of the furnace. The features of azimuthal flows formed in the areas of electric arcs and hearth electrodes were analyzed. Results showed that the multivortex structure of the flows that formed in the furnace allowed the volume of stagnant zones to be reduced and provided acceptable melt mixing conditions. The results can be used to improve the energy and structural parameters of three-electrode arc furnaces.

A Numerical Study of Laminar and Turbulent Heat Transfer in a Periodically Corrugated Wall Channel

1985 ◽  
Vol 107 (3) ◽  
pp. 564-569 ◽  
Author(s):  
R. S. Amano
Keyword(s):  
Heat Transfer ◽  
Turbulent Flows ◽  
Solution Method ◽  
Numerical Study ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Complex Flow ◽  
Flow Phenomena ◽  
Corrugated Wall ◽  
Laminar And Turbulent Flows

A numerical study is reported on hydrodynamic and heat transfer characteristics in a periodically corrugated wall channel for both laminar and turbulent flows. For turbulent flows the k-ε turbulence model with a refined near-wall model is adopted for the computation of the flow field for step ratios H/W ranging from two to four. The Reynolds number considered in this study varies from 10 to 25,000. The solution method of the governing transport equations is based on the modified hybrid scheme. As a result of extensive computations, the complex flow patterns in the perpendicularly corrugated wall channel are clarified and the mechanisms of heat transfer are explained relating to the flow phenomena of separation, deflection, recirculation, and reattachment. Finally it was observed that the effect of the step ratio on the local Nusselt number is minor. Moreover, it was found that both skin friction and heat transfer patterns change drastically from laminar to turbulent flows.

scholarly journals NUMERICAL STUDY OF HEAT TRANSFER IN TURBULENT FLOWS, WITH APPLICATION

2015 ◽  
Vol 13 (3) ◽  
pp. 77-82
Author(s):  
Laura-Alina STIKA ◽  
◽  
Valeriu-Alexandru VILAG ◽  
Mircea BOSCOIANU ◽  
Gheorghe MEGHERELU ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Turbulent Flows ◽  
Numerical Study

A Numerical Study of the Convective Heat Transfer in Low-Reynolds Number Turbulent Flows in Corrugated Pipes

2012 ◽  
Author(s):  
Ramin K. Rahmani ◽  
J. Eric Arnold ◽  
George W. Kraus
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Convective Heat Transfer ◽  
Turbulent Flows ◽  
Convective Heat ◽  
Numerical Study ◽  
Internal Flow ◽  
Eddy Simulation ◽  
Corrugated Surfaces ◽  
The Impact

Enhancement of convective heat transfer in internal turbulent flows with low-to-moderate Re number has been the subject of numerous studies, due to its vast applications. Corrugated surfaces can be used as enhancement devices in the heat convection systems. An ideal corrugation, for heat transfer in internal flow applications, provides a higher heat transfer rate with minimized pressure drop. The ratio of heat flux to the pressure drop can be used to determine the efficiency of a design. Using Large-Eddy Simulation, the heat transfer in low-Re turbulent flow in a pipe is studied to investigate the impact of different corrugated profiles with similar hydraulic diameter.

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