• Journal of Korean Society of Water and Wastewater
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• v.28 no.2
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• pp.217-223
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• 2014

In order to suggest the methodology for improving the equity of flow distribution in open channel with multiple outlet, CFD simulations were carried out for actual scale distribution channel being operated in domestic G_WTP(Water Treatment Plant). Also, before and after installing the longitudinal multi hole(diameter=250 mm, 116 holes) baffle suggested by this research, turbidity measurements data were collected for evaluating the effects of hydraulic modification for inlet flow equity. From the both results, total turbidity of settled water was lowered by 30 % and equity of flow distribution was improved about 60 % compared with before hydraulic structure modification.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.585-589
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• 2009

Extruder is divided to greatly three part at extrusion process. First, by hopper(Hopper) second, barrel(Barrel) with Screw that is point of extruder and third that is raw material supply wealth extrusion into dies(DIES) Part that decide shape of do product greatly divide. Hopper is role that distribute in raw material supply wealth (Feeding zone) of Screw preserving raw material in state of high quality how at extrusion process, and make distributed raw material as Screw in barrel rotates and 3 stage and inflicting heat and pressure raw material melting(Melting) state. And raw material of melting state Screw's measuring stoker(Metering zone) whereabouts anaphora do and product is completed through pipe channel of dies. Dies that is the most important as Screw in extrusion is part that is last part of melting state process of raw material and causes huge effect in quality of product. If more than design of dies happens, manufacture itself of dies is hard, but there are a lot of amount of losses accordingly. In this research, make pipe channel that raw material of melting state flows in dies can present dies basic design method through flow analysis of ideal pipe channel using CFdesign.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.6
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• pp.441-446
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• 2007

An experimental study on the countercurrent two-phase flow in narrow rectangular channels has been peformed. Countercurrent flow limitation (CCFL) was investigated using air and water in 760mm long, 100mm wide, vertical test sections with 1 and 3mm channel gaps. Tests were systematically performed with downward liquid superficial velocities and upward gas velocities covering 0 to 0.125 and 0 to 3.5m/s ranges, respectively. As the gap width of rectangular channel increased the CCFL water superficial velocity decreased for the given air superficial velocity. Slight increase of the air superficial velocity resulted in the abrupt decrease of water velocity when $j_g=2{\sim}4m/s$. The critical superficial velocity of air, at which the downward flow of water was no longer allowed, also decreased with the increase of gap width. The experimental results were compared with the previous correlations, which were mainly for round tubes, and the qualitative trends were found to be partially acceptable. However the quantitative discrepancies were hardly neglected. New correlation of CCFL was developed and showed good agreement with the experimental data.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.127-130
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• 2009

The uniform gas distribution between anode channels of the indirect internal reforming type molten carbonate fuel cell (MCFC) is crucial design parameter because of the electric performance and the durability problems. A three-dimensional computational fluid dynamics (CFD) analysis is performed to investigate flow characteristics in the anode channels and manifold under different pressure drop and channel temperature conditions. The combined meshes consists of hexadral meshes in the channels and polyhedral meshes in the manifold are adopted and chemical reactions inside the MCFC system are not included because of computational difficulties associated with the size and geometric complexity of the system. Results indicate that the uniformity in flow-rate is in the range of $\pm$ 0.048 % between the anode channels when the pressure drop of anode channel is about 150 Pa. A gas flow-rate uniformity decreases as the pressure drop of anode channels decreases and as the temperature difference between indirect internal reforming (IIR) channels and anode channels increases.

• Journal of the Korean Geophysical Society
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• v.7 no.2
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• pp.151-155
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• 2004

To solve the urban flood problems, it must get the enough channel conveyances and pumping capacities. It needs set up the detention system to control the flow over the channel capacity. Inspite of this detention system, the peak flow may increased by rainfall distribution and the delay of flow. This shows a design model of detention system which can consider the time problems from mutual connections of the detention storages and pumping flow using IDP(Incremental Dynamic Programming) method.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.279-284
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• 2021

In this study, the performance and distribution of fluid concentration, pressure, and current density of a proton exchange membrane fuel cell was investigated. In this paper, the two different types of flow field design were compared, singel channel and 5-channels. As a result, the 5-channels of flow field showed the better performance than that of single chanel. Especially, the single channel showed better performance in terms of mass transfer loss area.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1172-1177
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• 2008

Diverging channel from gas burner exit to the inlet section of Heat Recovery Steam Generator (HRSG) has been re-designed for 1 MW steam supply and power generation system. Three different test geometries have been chosen for the numerical simulation. The existing design for 300 kW HRSG system (CASE B) has been improved by geometry and position changes of inlet guide vanes along with gas velocity entrance angle at the diverging channel inlet (CASE C). Both cases has been compared with the case where hot combustion gas is directly injected without any guide vanes (CASE A). Improved design shows overall uniform velocity and temperature distribution compared to existing design.

• Analytical Science and Technology
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• v.26 no.1
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• pp.34-41
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• 2013

Split-flow thin cell (SPLITT) fractionation (SF) is a rapid separation technique capable of separating colloidal particles or macromolecules into two or more fractions. SF allows fractionations in a preparative scale as sample is fed continuously. Generally SF uses a thin ribbon-like channel equipped with two flow stream splitters at the inlet and outlet of the channel. Thus there exist two flow inlets and two flow outlets at the top and bottom of the inlet and outlet of the channel, respectively. There are two operating modes in SF, conventional mode and full-feed mode (FFD). Although the resolution in the FFD mode is lower than that in the conventional mode, FFD mode has some merits. The design of the channel and operation are simpler in the FFD mode, as it does not require the feeding of the solvent. Thus there is no flow stream splitter at the channel inlet, and only one pump is needed, unlike the conventional mode, where two pumps are required for the feedings of the sample and the solvent separately. Also the sample is not diluted in the FFD mode as there is no solvent feeding, which is important for fractionation samples with low colloidal concentrations such as environmental samples. For some of environmental samples, pre-concentration is often required. In this study, a new large-scale splitter-less FFD-SF channel was implemented, where there is no splitter at the outlet as well as at the inlet of the channel. It was possible to build the channel in a much larger dimension than conventional ones, allowing much higher sample throughput (TP). The new channel was tested and optimized with polyurethane (PU) latex beads, and then applied to large-scale separation of Polyacrylate (PA).

• Journal of computational fluids engineering
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• v.19 no.4
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• pp.86-93
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• 2014

Increased demand of power-transformer's capacity inevitably results in an excessive temperature rise of transformer components, which in turn requires improved radiator design. In this paper, numerical simulation of the cooling performance of an ONAN-type (Oil Natural Air Natural) radiator surrounded by air was performed by using CFX. The natural convection of the air was treated with the full-model. The present parametric study considers variation of important variables that are expected to affect the cooling performance. We changed the pattern and cross-sectional area of flow passages, the fin interval, the flow rate of oil and shape of flow passages. Results show that the area of flow passage, the fin interval, the flow rate of oil and shape of flow passages considerably affect the cooling performance whereas the pattern of flow passages is not so much influential. We also found that for the case of the fin interval smaller than the basic design, the temperature drop decreases while a larger interval gives almost unchanged temperature drop, indicating that the basic design is optimal. Further, as the flow rate of oil increases, the temperature drop slowly decreases as expected. On the other hand, when the shape of flow passages are changed, temperature drop is increased, indicating that the cooling performance is enhanced thereupon.

• Journal of computational fluids engineering
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• v.17 no.3
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• pp.93-98
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• 2012

The injection molding process is suitable for manufacturing complicated plastic products. As the customer request higher quality products increase, realization of the precise dimensional and shape controls is getting more important. For this purpose it is important to obtain uniform cooling procedure over the whole surface of the high temperature molded plastic. Failure to this may lead to different shrinkage speed, internal stresses and unwanted shape deformations. It is necessary to distribute coolant flow rates to the main channel and to the sub-channels properly to insure uniform cooling process when there are parallel cooling channels. In this study, three-dimensional turbulent flow simulations for representative parallel cooling channels were performed. To insure the intended flow rate to each sub-channels, various shape designs for the channel system were investigated. The results show that as the Reynolds number increases the effect of shape design is more profound. Through the proper flow distribution, uniform cooling effects would be expected.