• 한국대기환경학회지
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• 제19권6호
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• pp.733-743
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• 2003

The flow field in multiple fluid sphere systems was studied analytically. The expanded zero vorticity cell model based on Kuwabara's theory (1959) was applied and the effects of gas slippage at the collecting surface were considered. Also, the solid sphere system was extended to fluid sphere including the effects of the induced internal circulation inside the liquid droplet spheres or gas bubble systems. As a result, the obtained analytic solution was converged to the existing solutions for flow field around solid and bubble sphere systems with proper boundary conditions. Based on the resolved flow field, the terminal velocity around the collecting fluid spheres was obtained. Subsequently, this study evaluated the most general solution for flow field around the multiple fluid sphere systems. The obtained flow field in multiple fluid sphere could be used as a fundamental consideration of wet scrubber design and devices for removing particles by fluid-fluid interactions.

• 청정기술
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• 제9권4호
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• pp.189-196
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• 2003

고온 연료가스 정제를 위하여 ZnO-CuO 혼합탈황제를 제조하였으며, 탈황제들의 반응특성을 조사하였다. ZnO와 CuO의 혼합비율에 따른 황화반응 속도는 CuO의 함량이 증가할수록 빨라졌다. ZnO와 CuO 비율을 달리한 각 탈황제의 재생특성을 조사하기 위하여 TPO실험을 수행한 결과, $400^{\circ}C$ 이상에서 $CuSO_4$가 생성되고 $700^{\circ}C$ 이상에서 $CuSO_4$가 열분해 됨을 알았다. $600^{\circ}C$에서 재생된 탈황제는 $CuSO_4$에 의한$SO_2$ slippage 현상이 관찰되었으나, $700^{\circ}C$에서 재생할 경우에는 $SO_2$ slippage가 관찰되지 않았다. 이로써 ZnO와 CuO의 혼합으로 CuO는 ZnO의 휘발을 억제하고, ZnO는 CuO에 대한 $SO_2$ slippage를 최소화 시켰다.

• 에너지공학
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• 제13권1호
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• pp.75-81
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• 2004

본 연구에서는 ZZF탈황제의 내마모성을 개선하기 위하여 산화칼슘함량을 1, 3, 5, wt%정도 첨가한 탈황제를 제조하여 마모실험을 수행하였다. 마모실험전과 후의 탈황제 형상을 SEM으로 관찰하고 입자크기분포를 쿨터계수기로 측정하였다. 산화칼슘을 첨가하지 않은 ZZF 탈황제의 마모도는 Al=28.3%, CAI=10.8% 정도였다. CaO 함량이 3 wt%인 ZZFCa-3 탈황제의 마모도(Al=17.3%, CAI=8.8%가 가장 낮았다. ZZFCa 3 탈황제가 입자모양과 평균입도가 잘 유지되었다 ZZFCa-3 탈황제의 황화 및 재생실험을 수행하였다. 석탄가스 중의 10000 ppm수준의 H$_2$S를 1 ppm 이하로 정제할 수 있었으며, 탈황제의 황수용능력은 최대 28.8 g S/100 g sorbent정도 유지되었다. 재생된 탈황제의 XRD분석에서 CaSO$_4$실 생성은 관찰되지 않았으며, 황화반응에서도 SO$_2$ slippage가 관찰되지 않았다. 이러한 결과로 국내 고유 기술에 의한 반응성, 내구성, 내마모성이 모두 만족되는 고온건식 탈황제를 개발할 수 있었다.

• 한국수소및신에너지학회논문집
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• 제18권4호
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• pp.406-412
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• 2007

An experimental study on the design of a catalytic combustor for 1.6 kW MCFC system has been performed. The roles of the catalytic combustor are to completely burn anode off-gas and to supply sufficient $CO_2$ to cathode channels. In order to avoid hot spot or fuel slippage, flow uniformity at the catalyst inlet was achieved by installing two crossing perforated plates between the catalyst and the mixing chamber with minimal pressure drop. A Pd/Ce/Ni-$Al_2O_3$ catalyst was used for complete combustion of the off-gas at GHSV=36,000.

• 대한의용생체공학회:의공학회지
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• 제29권2호
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• pp.132-138
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• 2008

We investigated the biomechanical properties of a newly designed self-expansion type anterior cruciate ligament (ACL) anchor. The ACL anchor consists of the ring section giving the elastic force, the wedge for maintaining in contact with the femur tunnel wall and the link suspending hamstring graft or artificial ligament. The main design parameters that determine the performance of this device were the expansion angle (${\theta}$) and the thickness ($t_R$). The Ti6Al4V anchors were heated after inserting in a jig for 1 hour at $800^{\circ}C$ in a protective argon gas atmosphere and allowed to cool to room temperature in the furnace. In order to investigate the influence of the expansion angle and the thickness of the ring on the biomechanical properties of the anchor, the maximum pull-out load, stiffness and slippage of the ACL anchor were measured using the pull-out tester, and statistical analyses were also executed. The present results showed that the design parameters gave a significant effect on the performance of the self- expansion type of anchor. The pull-out load of the ACL anchors significantly increased as the thickness of the ring section was increased, having a similar trend for both expansion angles. The ACL anchor showed about 2.5 times higher values of the pull-out load than that of the minimum load (500N)required for the "accelerated rehabilitation". The optimum ${\theta}$ and $t_R$ values of this ACL anchor were suggested to have sufficient resistance against the pull-out force, high stiffness and relatively low slippage after ACL reconstruction.