• Journal of computational fluids engineering
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• v.19 no.1
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• pp.73-79
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• 2014

Three-dimensional turbulent flows of a distribution manifold are studied by a turbulence model. To investigate the geometrical effects of the manifold, the length and area of exit port are changed. From the results, flow structures related to the outflow uniformity are examined and the deparure angles are obtained. The exit configuration depending on the departure angle has advantages to the outflow uniformity. That is, the decreased exit area in the streamwise direction improves the uniformity of exit flow. For the uniform effusion, the change of exit port by departure angle is more effective them the change of exit area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4718-4725
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• 2011

Intake-air flow and distribution characteristics of the 1600cc gasoline engine intake manifold have been studied using the computer simulation. Simulation has been conducted using both one-dimensional performance simulation and three-dimensional CFD software. Steady state flow simulation result of the intake manifold shows good distribution characteristics that the standard deviation of flow coefficients is below 1.0 percentage for both one- and three-dimensional simulation. Even though one-dimensional simulation result slightly overestimates compared with three-dimensional simulation result, both results show very good agreement in flow coefficient trend. Also, unsteady state simulation result shows consistent distribution characteristics with that of steady state. It is shown that unsteady state distribution characteristics might be able to be predicted through the steady state mass distribution result.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.625-630
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• 2014

연료전지의 성능을 결정짓는 가장 중요한 변수 중의 하나는 각 스택의 채널에 얼마나 균일하게 연료를 공급할 수 있느냐이다. 본 연구에서는 네 가지의 모델을 사용하여 연료전지 매니폴드 형상에 따른 최적 설계를 수행하였다. 위 네 가지 모델은 각기 다른 기하학적 형상을 가지며 Edison CFD를 이용하여 형상 내의 유동을 비교하였다. 초기 모델에서는, 입구부에서 매니폴드로 유입되는 유동의 확산이 잘 일어나지 않아 각 채널의 질량유량이 불균일한 분포를 보였으며 특히 속도가 빠른 중심 영역의 채널에 많은 연료가 유입되었다. 이를 위한 디퓨져 모델링이 제안되었으며 실속이 최소한도로 발생할 때 채널당 질량유량이 가장 균일하다고 가정하였다. 이를 위해 다양한 디퓨져 각을 가진 모델을 사용했고, 이론상으로 실속이 발생하지 않는 형상에서 가장 균일한 분포를 보임을 확인하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.3
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• pp.176-185
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• 2009

A general flow distribution model and a simple process of numerical analysis, which can be applied to multi-pass systems with manifolds, are presented. A numerical procedure, namely a modified equal pressure method based on the discrete model, was developed to predict flow rates at branch tubes. The predicted pressure distribution agreed well with the previous research with the average error less than 11%. A parametric study was performed to demonstrate the effect on the flow distribution.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2280-2285
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• 2008

A general flow distribution model and a simple process of numerical analysis, which can be applied to multi-pass systems with manifolds, are presented. Correlations are derived from the discrete model, and numerically calculated using a modified equal pressure method. The predicted pressure distribution agrees well with the available experimental results of other researchers with the average error less than 2% for 10 branch manifolds, and 4% for 20 branch manifolds. A parametric study is performed to demonstrate the effect on the flow distribution.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.534-537
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• 2009

최근 자동차 배기가스 규제가 더욱 강화됨에 따라 완전 연소를 통한 배기가스 저감에 관하여 많은 연구가 진행되고 있다. 특히, 고온 연소시 문제가 되는 질소 산화물의 저감을 위해 많은 노력을 기울이고 있다. 질소 산화물을 저감하는데 효과적인 EGR 기술의 도입이 보편화되고 있지만, 각 실린더별 EGR 분배 특성에 따라 엔진의 성능이 달라지는 역효과가 발생한다. 시제품을 동한 EGR 분배특성 파악은 비용과 시간 측면에서 상당한 난제가 산재해있다. 본 연구에서는 이러한 실험시간과 비용 절감을 위하여 1D 성능해석 프로그램인 GT-Power를 적용 EGR의 분배특성을 예측하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.320-323
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• 2006

A numerical study is made of a manifold and bipolar plate in polymer electrolyte fuel cells, the aim of the present study is to describe the characteristics of flow pattern In manifold and bipolar plate. The present work shows that the flow pattern in the bipolar plate is affected by the penetration flow through GDL characterized by clamping pressure and GDL intrusion in to a channel area. Manifold geometry also affects the flow distribution. The recirculation flow by bent duct destroy even distribution In manifold, the present work shows that corner rounding can improve the manifold performance.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.47-54
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• 2022

In this study, we performed numerical analysis for 1 kWe SOFC stack of internal manifold types according to the different manifold sizes to verify the influence of the flow uniformity into each cell. To simulate the flow phenomena in the stack, the continuity and momentum conservation equations including the standard k-𝜺 turbulent model for the steady-state conditions were applied. From the calculation results, we verified that the pressure drop from inlet pipes to outlet pipes decreased to a log scale as the manifold size increased in the internal manifold types. Also, we found that the flow uniformity increased on an exponential scale as the manifold size increased. In addition, the calculation results showed that the flow uniformity gradually improved as the fuel and oxygen utilization increased.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.2
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• pp.161-168
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• 2016

CNG engine has been used as a transportation because of higher thermal efficiency and lower CO2 and particulate matter. However its out put power is decreased due to cylinder-to-cylinder variation during the supply of air-fuel mixture to the each cylinder. It also causes noise and vibration. So in this study, 1D engine simulation model was validated by comparison with experiment data and 3D CFD simulation was conducted to steady-state flow analysis about each manifold geometry. Then, the effects of various intake manifold geometries on variation were evaluated by using 1D-3D coupling analysis at engine speed of 2100 rpm range in 12 L CNG engine. As a result, variation was improved about 4 % though 3D CFD analysis and there was a variation within 3 % using 1D-3D coupling analysis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.269-273
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• 2011

In present paper focused on the influence of the inlet-outlet area ratio of counter flow manifold on the flow distribution and pressure drop characteristics of a tubular heat exchanger. The characteristics of flow distribution and pressure loss can be obtained depending on the inlet-outlet area ratio. In this paper, a tubular heat exchanger can be designed with minimum flow mal-distribution and better characteristic of pressure loss by choosing the optimum inlet-outlet area ratio.