• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.523-534
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• 1998

The convection heat transfer on horizontal circular tube is studied as a conjugated heat transfer problem. With uniform heat generation in a cylindrical heater placed in a cross flow boundary condition, heat flow that is conducted along the wall of the heater creates a non-isothermal surface temperature and non-uniform heat flux distribution. In the present investigation, the effects of circumferential wall heat conduction on convection heat transfer are investigated for the case of forced convection around horizontal circular tube in cross flow of air and water. Non-dimensional conjugation parameter $ K^*$ which can be deduced from the governing energy differential equation should be used to express the effect of circumferential wall heat conduction. Two-dimensional temperature distribution$ T({\gamma,\theta})$ is presented. The influence of circumferential wall heat conduction is demonstrated on graph of local Nusselt number.

• Journal of Welding and Joining
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• v.21 no.3
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• pp.30-34
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• 2003

This paper describes the heat distribution characteristics of ASTM A131DH36 high tensile steel for ship structures in 5㎾ $CO_2$ laser welding. In general, high energy of laser beam concentrates on the small area of the weldment instantaneously; therefore, this heat transfer mechanism induces the rapid changes of temperature and mechanical characteristics in laser welds this mechanism. So temperature distribution analysis is important to understand mechanical characteristics of laser welds. Authors have conducted finite element simulation to analyze the heat distribution characteristics in laser welds. The result of simulation has been verified by comparing with the metallurgical experiment result. From the result of this study, we can accurately predict the heat distribution characteristics in laser welds by using numerical simulation.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.162-170
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• 2001

In torch weaving in arc welding on V groove, the heat input distribution on groove surface is a main factor determining the bead shape and the weld quality with and without the weld defects such as undercut, overlap, etc. In this study, we calculate the heat input varying with the welding current, arc voltage, welding speed and the touch weaving condition using numerical method. And we investigate the heat input distribution on groove surface while applying the various grooves having 2 dimensional heat sources.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.251-257
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• 2000

A numerical simulation of the temperature rise for sliding surface in dry contact is based on Jaeger's formula combined with a calculated heat input. A gear tooth temperature analysis was performed. The pressure distribution has the Hertzian pressure distribution on the heat source. The heat partition factor is calculated along line of action. A Temperature distribution of tooth surface is calculated about before and after profile modification. A Temperature of addendum and deddendum in modified gear have reduced.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.2
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• pp.331-337
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• 2001

A numerical simulation of the temperature rise for sliding surface in dry contact is based on Jaegers formula combined with a calculated heat input. A gear tooth temperature analysis was performed. The pressure distribution has the Hertzian pressure distribution on the heat source. The heat partition factor is calculated along ling of action. A Temperature distribution of tooth surface is calculated about before and after profile modification. A Temperature of addendum and deddendum in modified gear have reduced.

• Journal of the Korean Society of Safety
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• v.13 no.1
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• pp.26-33
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• 1998

This paper subdivided the interior solid into triangular shape of equal size to calculate the temperature distribution around the square heat source of it, and compared calculated values with measured ones. The result obtained are as follows. 1) It was found that we can calculate the temperature distribution around the square heat source of interior solid by the variational method of the finite element method as the calculated values were almost accord with the measured ones. 2) The temperature distributed were higher when the distances between heat source were farther and lower when those nearer. 3) Vertical surface temperature distribution is remarkably efficient by thermal conductivities.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.10
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• pp.886-893
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• 2000

A good understanding of the heat transfer distribution is very important to suppress the deformation of steel products. In this study, the local heat transfer coefficients are experimentally investigated to understand the heat transfer distribution of thick steel plates with even flat spray nozzle. The steel slabs are cooled down from the initial temperature of about $1000^{\circ}C$ , and the local heat transfer coefficients and surface temperatures are calculated from the measured temperature-time history. The results show that the local heat transfer coefficients of spray cooling are dominated by the local droplet flow rate, and in proportion to becoming more distant from the center of heat transfer surface, the local heat transfer coefficients decrease with the decrease of the local droplet flow rate.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.763-768
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• 2002

This paper presents a mathematical model predicting the temperature distribution in rotating GMA welding. The bead width increases with rotation frequency at the same rotation diameter because the molten droplets are deflected by centrifugal force. The numerical solution is obtained by solving the transient three-dimensional heat conduction equation considering the heat input from the welding arc, cathode heating and molten droplets. Generally in GMA welding the heat input may be assumed as a normally distributed source, but the droplet deflection causes some changes in the heat input distribution. To estimate the heat flux distribution due to the molten droplet, the contact point where the droplet is transferred on the weld pool surface is calculated from the flight trajectory of the droplets under the arc plasma velocity field obtained from the arc plasma analysis. The numerical analysis shows a tendency of broadened bead width and shallow penetration depth with the increase of rotating frequency. The simulation results are in good agreement with those obtained by the experiments under various welding conditions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1242-1247
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• 2010

In this study, the heat source distributions at the end side and the center of the electrode are analyzed to estimate the electrical stress due to the harmonics from the nonlinear loads. The governing equation at the analysis area of low voltage condenser are numerically solved using the finite element software package to analyze the effects of heat source distribution due to the 5th and 7th harmonics, which can exist normally in the distribution network and can be applied to the low voltage condenser. Finally, the heat source distribution from the harmonics is compared and analyzed with the heat source distribution from the fundamental component of the applied voltage.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.1
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• pp.25-33
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• 2005

When a circular tube with uniform heat generation within the wall was placed in a cross flow, heat flows by conduction in the circumferential direction due to the asymmetric nature of the fluid flow around the perimeter of the circular tube The circumferential heat flow affects the wall temperature distribution to such an extent that. in some cases, significantly different results may be obtained for geometrically similar surfaces. In the present investigation, the effect of circumferential wall heat conduction is investigated for forced convection around circular tube in cross flow of air and water Two-dimensional temperature distribution $T_w(r,{\theta})$ is calculated through the numerical analysis. The difference between one-dimensional and two-dimensional solutions is demonstrated on the graph of local heat transfer coefficients. It is observed that the effect of working fluid is very remarkable.