화학공학소재연구정보센터
Journal of the Korean Industrial and Engineering Chemistry, Vol.15, No.6, 640-645, October, 2004
용융염-공기 이상흐름계에서 압력요동특성
Pressure Fluctuation Characteristics in a Molten Salt-Air Two Phase Flow System
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초록
공기-용융염(탄산나트륨) 이상흐름을 파악하기 위하여 용융염산화 반응기(직경 0.076 mX높이 0.653 m)내에서 압력요동을 측정한 후 이를 통계학적 방법을 이용하여 해석하였다. 기체유속(0.05~0.22 m/sec)과 용융염온도(870~970 ℃)가 압력요동, 상공간투영 그리고 Shannon entropy에 미치는 영향을 규명하였다. 압력요동과 최적시간 지연에서 2차원 상공간에 투영된 attractor는 용융염산화 반응기 내의 기-액 흐름특성을 예측하는데 사용되었다. Shannon entropy는 온도가 증가하면 증가하였으나 기체유속에 따라서는 감소하고 흐름영역에 따라서 다른 증가 경향을 나타내었다. 본 연구결과 상공간투영, Shannon entropy는 용융염산화 반응기 내에서 발생하는 기-액 이상흐름의 난류도와 비선형 흐름을 효과적으로 설명할 수 있는 방법이라는 것을 알 수 있었다.
Pressure fluctuation signals from a molten salt oxidation bed (0.076 m ID.X0.653 m H.) have been analyzed by adopting the stochastic method, to characterize the two-phase (air-molten sodium carbonate salt) flow behavior. Effects of input air flow rate (0.05~0.22 m/sec) and molten salt temperature (870~970 ℃) on the characteristics of the pressure fluctuation, phase space portraits and Shannon entropy have been studied. The attractor which has been constructed with the optimum time lag was utilized to predict the flow behavior of gas-liquid flow in the molten salt oxidation reactor. The Shannon entropy decreased with increase in molten salt temperature and increased gradually with increase in the gas flow rate, but it exhibited a different increasing tendency with the flow regime. It was found that the phase space portrait, the Shannon entropy can be utilized to explain the system turbulence and non0linear dynamic behaviors of two-phase flow in molten salt oxidation reactor.
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