• Composites Research
• /
• v.37 no.3
• /
• pp.190-196
• /
• 2024

The bipolar plate is a crucial element of the vanadium redox flow battery (VRFB) as it serves as both the electrical conduit and the structural support for the cell within the VRFB stack. Although, the graphite material is primarily used for the bipolar plate due to its excellent electrical conductivity, a significant limitation of performance of the VRFB is present due to high interfacial contact resistance (ICR) arises between the electrode and bipolar plate in the cell stack. This study aims to develop an integrated electrode-bipolar plate assembly that will address the limitations of the ICR. The integrated assembly was constructed using a single carbon felt with thermoplastic and thermoset polymers utilizing hot press method. Experimental results verify that the bipolar plate assembly exhibits reduced area specific resistance (ASR) due to the continuous electrical path. Additionally, from the charge/discharge cell test results, the integrated assembly shows improved cell performance. Therefore, the developed integrated electrode-bipolar plate assembly can serve as a substitute for the conventional bipolar plate and electrode assembly.

• Membrane Journal
• /
• v.16 no.4
• /
• pp.252-258
• /
• 2006

A numerical analysis was performed for a separation process of carbon dioxide from a flue gas stream using polyethersulfone hollow fiber membranes. Countercurrent flow governing equations were regarded to be two point boundary-value problem and the nonlinear ordinary differential equation were simultaneously solved using the finite- difference method. A computer program was developed using the Compaq Visual Fortran 6.6 software. The carbon dioxide permeate driving force and the fred gas residence time at the inside of membrane were found to be very important factors affecting the permeation characteristics of carbon dioxide. The carbon dioxide concentration in the permeate and the flow rate of the permeate were found to be slightly larger by a few percent with a countercurrent flow analysis than those with a cocurrent flow analysis.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2001.05a
• /
• pp.101-103
• /
• 2001

• Proceedings of the Membrane Society of Korea Conference
• /
• 2001.11a
• /
• pp.93-95
• /
• 2001

• Proceedings of the Membrane Society of Korea Conference
• /
• 2002.11a
• /
• pp.139-141
• /
• 2002

• Proceedings of the Membrane Society of Korea Conference
• /
• 2003.11a
• /
• pp.207-209
• /
• 2003

• Journal of Korea Water Resources Association
• /
• v.52 no.1
• /
• pp.1-10
• /
• 2019

This study investigates the flow characteristics, such as velocity distributions, size and location of recirculation zone, longitudinal flow change rates, and bifurcation discharge ratio in the bifurcation channel by TELEMAC-2D, a 2D numerical model. The numerical model is validated by previous experimental results and the numerical results are in relatively good agreement with the experimental results, such as the water surface elevation and velocity distribution in the channels. As the inertial force and moment in the main channel decrease, the bifurcation discharge ratio increases, and the relative high velocity distribution becomes wider and the reverse velocity of the main stream decreases in the branch channel. As the bifurcation discharge ratio increases, the size of the recirculation zone in the branch channel decreases and it can be more clearly calculated by determining the point where the longitudinal froude number $Fr{\approx}0$ as well as drawing the distribution of the streamline distribution.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.7
• /
• pp.1-12
• /
• 2004

A flow visualization of the 1st cycle motion of a fling-clapping wing that might be employed by butterflies during flight is performed. In this numerical flow visualization, he time-dependent Navier-Stokes equations are solved for two wing motion types; 'fling followed by clap and pause' and 'clap followed by fling and pause'. The result is observed regarding the main flow features such as the sequential development of the two families of separation vortex pairs and their movement. For the fling followed by clap and pause motion, a strong separation vortex pair of counter-clockwise develops in the opening between the wings in the fling phase and they then move out from the opening in the following clap phase. For the clap followed by fling and pause motion, the separation vortex pair developed in the outside space in the clap phase move into the opening in the following fling phase. The separation vortex pair in the opening developed in the fling phase of the clap followed by fling and pause motion is observed to be stronger than that in the opening developed in the fling phase of the fling followed by clap and pause motion.

• Korean Chemical Engineering Research
• /
• v.48 no.5
• /
• pp.598-602
• /
• 2010

In this paper, we carried out CFD modelling and simulation for the membrane system to separate H2 gas from the multi-component feed gas. The membrane system is of the annulus tubular type consisting of the external lumen side for the feed gas and the internal permeation side for the sweeping gas. The operating temperature and pressure of the lumen side inlet flow are $374^{\circ}C$ and 7 bar respectively and those of the sweeping gas are $374^{\circ}C$ and 3 bar, and considering these conditions, Pd membrane system was employed. CFD simulations were performed for the co-current flow and counter-current flow membrane system based on the flow directions between the feed and the sweeping gas. Comparisons and discussions were made for the H2 partial pressure, H2 mole fraction and H2 flux for both cases. Furthermore, we executed CFD simulations for the each case of the various inlet flow rates of the feed gas at the lumen side. Accordingly, we reviewed the effects of the flow rate and residence time on the performance of the membrane system.

• The Korean Journal of Financial Management
• /
• v.9 no.1
• /
• pp.177-192
• /
• 1992

본 논문에서는 MLP(master limited partnership) 분리(分離)라는 기업구조(企業構造) 개편(改編)(restructing)이 기업의 시장가치에 미치는 영향을 사건연구(事件硏究)(event study) 방법론을 통하여 분석하였다. 실증분석의 결과 MLP 분리(分離)로 인한 모기업의 주가상승이 통계적으로 유의한 것으로 나타났다. 세금혜택(稅金惠澤), 대리인(代理人) 문제(間題), 자금조달(資金調達) 그리고 자산증권화(資産證券化)(securitization) 둥의 측면에서 MLP 분리(分離)의 경제적 의미를 살펴보았다. 경영자에 의한 자유현금(自由現金)흐름(free cashflow)남용의 방지를 통한 대리인(代理人) 비용(費用)(agency cost)의 감소, 정보불균형(情報不均衡)에 관련된 자금조달상의 불이익의 극복가능성이 모기업의 주가상승을 가져올 수 있는 보다 중요한 요인들로 제시되었다. 이러한 요인들의 상대적 중요성에 대한 실증분석 특히 자유현금흐름 가설의 검증이 앞으로의 과제다.