A mathematical model for fluid flow in a weld pool at high currents

1980 ◽  
Vol 98 (4) ◽  
pp. 787-801 ◽  
Author(s):  
D. R. Atthey
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Weld Pool ◽  
Fluid Motion ◽  
Reynolds Numbers ◽  
Time Dependent ◽  
Inert Gas ◽  
Low Reynolds Numbers ◽  
Welding Arc ◽  
Time Dependent Problem

In order to determine the heat transfer inside a TIG (tungsten/inert gas) weld pool, it is necessary to have a good understanding of the flow patterns of the liquid metal. The principal force driving the fluid motion is the electromagnetic j × B force due to the current from the welding arc and its self-magnetic field. In this paper we consider the flow of a viscous incompressible conducting fluid in a hemispherical container due to various distributions of the electric current. The problem is posed as a time-dependent problem and is solved numerically using the Du Fort–Frankel leap-frog method. Results are presented for currents of 100 A flowing through the weld pool. This is a typical current for TIG welding, and corresponds to a Reynolds number in the range 200 < Re < 600. Previous solutions of the problem were restricted to low Reynolds numbers, i.e. low currents.

Heat transfer and drag for transverse flow past bundles of finned tubes at low reynolds numbers

1978 ◽  
Vol 14 (10) ◽  
pp. 905-907
Author(s):  
A. S. Lyshevskii ◽  
V. G. Sokolov ◽  
V. M. Sychev ◽  
L. Ya. Shkret
Keyword(s):  
Heat Transfer ◽  
Reynolds Numbers ◽  
Transverse Flow ◽  
Low Reynolds Numbers ◽  
Finned Tubes ◽  
Flow Past ◽  
Low Reynolds

scholarly journals Теплообмен при смешанной конвекции расплава соли в присутствии магнитных полей

2019 ◽  
Vol 45 (10) ◽  
pp. 27
Author(s):  
И.А. Беляев ◽  
Д.А. Бирюков ◽  
А.В. Котляр ◽  
Е.А. Белавина ◽  
П.А. Сардов ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Temperature Fluctuations ◽  
Reynolds Numbers ◽  
Transverse Magnetic ◽  
Statistical Characteristics ◽  
Transfer Coefficients ◽  
Gravitational Flow ◽  
Heat Transfer Coefficients ◽  
The Magnetic Field

The results of an experimental study of the salt melt downflow in a uniformly heated pipe under the influence of a strong transverse magnetic field are presented. The changes of heat transfer coefficients and statistical characteristics of temperature fluctuations under the influence of the magnetic field are investigated. The peculiarities of the transition of the viscous-gravitational flow in the viscous-inertial-gravitational flow at Reynolds numbers (Re=3000-5000) under the influence of the magnetic field (Ha=17) were studied.

Comparisons of Pins/Dimples/Protrusions Cooling Concepts for a Turbine Blade Tip-Wall at High Reynolds Numbers

2010 ◽  
Author(s):  
Gongnan Xie ◽  
Bengt Sunde´n ◽  
Weihong Zhang
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Computational Models ◽  
Reynolds Numbers ◽  
Low Reynolds Numbers ◽  
Gas Leakage ◽  
Leakage Flows ◽  
Blade Tip ◽  
High Reynolds ◽  
The Cost

The blade tip region encounters high thermal loads because of the hot gas leakage flows, and it must therefore be cooled to ensure a long durability and safe operation. A common way to cool a blade tip is to design serpentine passages with 180° turn under the blade tip-cap inside the turbine blade. Improved internal convective cooling is therefore required to increase blade tip lifetime. Pins, dimples and protrusions are well recognized as effective devices to augment heat transfer in various applications. In this paper, enhanced heat transfer of an internal blade tip-wall has been predicted numerically. The computational models consist of a two-pass channel with 180° turn and arrays of circular pins or hemispherical dimples or protrusions internally mounted on the tip-wall. Inlet Reynolds numbers are ranging from 100,000 to 600,000. The overall performance of the two-pass channels is evaluated. Numerical results show that the heat transfer enhancement of the pinned tip is up to a factor of 3.0 higher than that of a smooth tip while the dimpled-tip and protruded-tip provide about 2.0 times higher heat transfer. These augmentations are achieved at the cost of an increase of pressure drop by less than 10%. By comparing the present cooling concepts with pins, dimples and protrusions, it is shown that the pinned-tip exhibit best performance to improve the blade tip cooling. However, when disregarding the added active area and considering the added mechanical stress, it is suggested that the usage of dimples is more suitable to enhance blade tip cooling, especially at low Reynolds numbers.

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