• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.93-96
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• 2012

In the industrial furnaces or reactors, entrainment of the material particles is one of the important issues from the point of view of efficient material-use. The particles of solid phase which has submicron unit are easily entrained with gas phase as a reacting agent or product, and it causes a loss of the material. In this study, wind-tunnel experiment is carried out to interpret the distribution of the particles entrained along the tunnel length. Through CFD-based computational analysis of the experiment, availability of result from the CFD analysis associated with particle size distribution and gaseous velocity to practical system is evaluated.

• Journal of Biosystems Engineering
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• v.21 no.2
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• pp.117-122
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• 1996

Droplet sizes produced from a mist blower should be adequate to get highly biological effects with a reasonable level of work performance. However the droplet sizes from the conventional nozzles of the mist blower were around VMD 95 to 469$\mu$ which were relatively large as compared with the recommended droplet sizes in liquid flow rate of 17.2 m$/ell$s with air flow rate of 16660$m^3$/s on the maximum travel distance of about 4.0 m. The velocity of air stream at the point where two fluids, air and liquid, impact each other, was tried to maximize as much as possible in order to enhance the atomization performance of a newly designed twin fluid nozzles with the same or better level of performance of the conventional mist blower, The configuration of nozzle orifice should be designed to enlarge the contact area between air and liquid to enhance the atomization.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.61-66
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• 2002

The nonlinear differential equations of motion of a fluid conveying curved pipe are derived by use of Hamiltonian approach. The extensible dynamics of curled pipe is based on the Euler-Bernoulli beam theory. Some significant differences between linear and nonlinear equations and the dynamic characteristics are discussed. Generally, it can be shown that the natural frequencies in curved pipes are changed with flow velocity. Linearized natural frequencies of nonlinear equations are slightly different from those of linear equations.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.20 no.4
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• pp.309-332
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• 2016

Finite element method has been applied to solve the fundamental governing equations of natural convective, electrically conducting, incompressible fluid flow past an infinite vertical plate surrounded by porous medium in presence of thermal radiation, viscous dissipation, Soret and Dufour effects. In this research work, the results of coupled partial differential equations are found numerically by applying finite element technique. The sway of significant parameters such as Soret number, Dufour number, Grashof number for heat and mass transfer, Magnetic field parameter, Thermal radiation parameter, Permeability parameter on velocity, temperature and concentration evaluations in the boundary layer region are examined in detail and the results are shown in graphically. Furthermore, the effect of these parameters on local skin friction coefficient, local Nusselt number and Sherwood numbers is also investigated. A very good agreement is noticed between the present results and previous published works in some limiting cases.

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.148-152
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• 1996

A transient two-dimensional (2D) model was developed for investigating the heat and fluid flow in old pools and determining velocity profile and temperature distribution for the Gas Metal Arc (GMA) welding process. The mathematical formulation deals with the driving farces (electromagnetic, buoyancy, surface tension and plasma drag forces) as well as energy exchange between the molten filler metal droplet and weld pools. A general thermofluid-mechanics computer program, PHOENICS, was employed to numerically solve the governing equation with the associated source terms. The results of computation have shown that the electromagnetic and surface tension farces as will as the molten filler metal droplet have major influence in shaping the weld pool geometry.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.1 s.232
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• pp.1-8
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• 2005

Laser melting problems with deformed substrates are investigated by axisymmetric numerical simulations. Source-based method is used to solve the energy equation, and the momentum equations are solved in the liquid domain with SIMPLER algorithm. Using a laser beam with a top-hat heat flux distribution, this study is performed to examine the effect of surface deformation, beam power density and surface tension force on the molten pool during laser melting. Surface temperature decreases with increasing surface deformation, while surface velocity increases. It is found that surface deformation, beam power density and surface tension force have a very significant effect on heat transfer and fluid flow during laser melting.

• The KSFM Journal of Fluid Machinery
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• v.20 no.1
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• pp.29-34
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• 2017

An analysis on pressure drop in vortex amplifier has been performed. Based on theoretical approach with flow physics on well-known firm ground from previous studies, two dimensional flow model, which is very useful to calculate pressure drop of vortex amplifier, is proposed. Parametric studies on inlet and outlet boundary conditions also have been performed so that it found the most influential parameter is the inlet swirl velocity condition. Finally, a simple formulation is given to calculate total pressure drop.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.123-128
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• 2001

Numerical simulation is conducted to clarify the heat transfer and fluid flow characteristics of brake shoe for freight car. High order up-wind scheme for governing equations, k-epsilon turbulent model and SIMPLEC algorithm based on finite volume method are used to solve the physical shoe model. The governing equations are solved by TDMA(Tri-Diagonal Matrix Algorithm) with line-by-line method and block correction. From the results of simulation, the characteristics of cooling pattern is strongly affected by the velocity of train and the material of shoe. The face lift of shoe affects on the temperature distribution of rear surface of shoe as well as the front surface of that. Due to the grooves in shoe, it will be expected to cool the frictional heat and result in the reduction of maintenance efforts.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.704-708
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• 2017

A spray characteristics is carried out in a numerical simulation of swirl coaxial injector. The water and nitrogen are the oxidizer and fuel is used in cold flow condition. The simulation is carried out in 3d model with varying recess length. Reynolds stress turbulence and volume of fluid model were chosen to perform the simulation. The spray characteristics have been investigated as well as the influence of the inlet swirl strength of the internal flow. Effect of recess length is studied for the axial and radial velocity decreased with a reduced length of inner injector due to the decline vortex intensity.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.07a
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• pp.243-246
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• 2012

A new multi inner stage(MIS) cyclone was designed to remove the acidic gas and minute particles of harmful materials produced from electronic industry. To characterize gas flow in MIS cyclone, pressure and velocity distribution were calculated by means of computational fluid dynamics(CFD) commercial program. Also, the flow locus of particles and particle removal efficiency were analyzed by Lagrangian method. When outlet pressure condition was -1,000 Pa, the efficiency was the best in this study. Based on the CFD simulation result, the pressure loss and destruction removal efficiency was measured through MIS cyclone experiment.