• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.350-356
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• 2011

In this paper, we proposed the automatic cutting mechanism of the perforation pipes in an automobile muffler. This cutting mechanism makes continuous work possible, because it performs the batch work via the sequential operation of loading, feeding, cutting, and discharging. The proposed cutting mechanism consists of the frame unit, escape unit, turning unit, feeding unit, vision system, clamping unit, spindle/cutting unit and cooling unit. And, these mechanisms have been modularized through mechanical, dynamical and structural optimized design using the SMO (SimDesigner Motion) analysis module. Also, the virtual prototype was carried out using the 3-D CAD program. The cutting process cycle is performed in the order of loading, vision processing, feeding, clamping, cutting and discharging. And the cycle time for cutting one piece was designed to be completed in four seconds.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1225-1230
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• 2004

In this paper, the pressure drops were investigated according to the sintered porous wick structure in loop heat pipe(LHP) by theoretical analysis. LHP has the wick only in evaporator for the circulation of working fluid, so utilizes porous wick structure which pore diameter is very small for large capillary force. This paper investigates the effects of different parameters on the pressure drops of the LHP such as particle diameter of sintered porous wick, wick porosity, vapor line diameter, thickness of wick and heating capacity. Working fluid is water and the material of sintered porous wick is copper. According to the these different parameters, capillary pressure, pressure drop in wick were analized by theoretical design method of LHP.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.4
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• pp.825-832
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• 1988

An experiment was performed to study the heat pipe phenomenon of porous media heated above at one-dimensional steady state for the range of heat flux, 300 W/ $m^{2}$ ~ 2000w/ $m^{2}$. Glass beads, sand, and copper particles were used as porous media and distilled water was used as a working fluid. Result of experiment shows that the length of the two-phase zone increases with the decreasing particle size for the same heat flux. At relatively lower heat flux the length of the two-phase zone increases with the increasing heat flux, which contradicts the result of earlier work. However, its length remains nearly constant when the heat flux increases above a certain value. The length of the two-phase zone is proportional to the product of the heat flux by the hydrostatic capillary height under the limited value on heat flux, that is, $l_{t}$ = A(q. $l_{cap}$)+B, q.leg.1/A(C+B/ $l_{cap}$) where A is 1.7*10$^{-4}$ $m^{2}$/w, B is 1.9*10$^{-2}$ m, and C is 0.43 for copper particles and 0.31 for glass beads and sand.d.d.d.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.358-367
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• 2013

In the present paper, we apply a porous modelling technique to accurately predict the pressure drop through the strainer by replacing all or some of the filter composed of perforated plates with porous media and there imposing the streamwise and transverse loss coefficients required according to the Forchheimer law and then confirm its effectiveness. At first, the streamwise coefficient is obtained by performing a simple simulation on the pipe flow mimicking the hole flow. Subsequently, the transverse coefficient is obtained by setting a unit pattern to have common flow loss characteristics with the repeated shape patterns in the filter, then performing numerical simulations on the prototype and porous model of the unit shape pattern, and finally comparing their results of pressure drop. To validate the applied modeling technique, we perform the numerical simulation with the two specified loss coefficients on a whole shape of strainer and compare the modeling results with those of the corresponding prototype numerical simulation. Comparison indicates that the modeling technique can predict the pressure drop and flow characteristics comparatively accurately and save the number of nodes closely related to the computational cost (CPU and memory) by about 3~4 times compared with the prototype simulation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.427-428
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• 2009

The authors investigated anomalous nanoporous structures of aluminum oxides during the Al anodization process. We implemented two-steps anodizing process for the electrolyte of oxalic acid. As increasing DC voltages, lattice constants are proportionally increased. For the curved surface, the surface electric field was distorted so that the nanoporous pipe channel changed to a cone-type shape. We confirmed the periodicity by using the FFT(Fast Fourier Transform) analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.1
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• pp.18-24
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• 2001

Woven wire wick is very effective structure because of its easiness to insert inside of pipe for a miniature heat pipe. The present study was conducted to investigate the effect of the effective flow passage with respect to wire helix angle. Also effective thermal conductivity were examined by defining mean porosity considering effective liquid flow passages. Effective heat transfer area is varied with respect to wire helix angle, and in the range of $\thet=60~65^{\circ}C$, heat transfer area is decreased about 15~20%. Permeability of woven wire wick shows similar value of 200 mesh screen wick. And comparison of experimental results on effective thermal conductivity shows a fairly good agreement with the analytical results.