전산유체역학을 이용한 실규모 오존 접촉에서의 수리거동과 유효 체적 평가에 관한 연구 = Evaluating Effective Volume and Hydrodynamic Behavior in a Full-Scale Ozone Contactor with CFD Simulation

다국어 초록 (Multilingual Abstract)

An Ozone reaction model combined with CFD(Computational Fluid Dynamics) technique was developed in this research. In the simulation of ozonation, hydrodynamic behavior as well as reaction model is important because ozone is supplied to treated water as gas ozone. In order to evaluate hydrodynamic behavior in an ozone contactor, CFD technique was applied. CFD technique elucidated hydrodynamic behavior in the selected ozone contactor, which consisted of three main chambers. Three back-mixing zones were found in the contactor. The higher velocities of water were observed in the second and third compartments than that in the first compartment. The flow of the opposite direction to the main flow was observed near the water surface. Based on the results of CFD simulation, the ozone contactor was divided into small compartments. Mass balance equations were established were established in each compartment with reaction terms. This reaction model was intended to predict dissolved ozone concentration, especially. We concluded that the model could predict favorably the mass balance of ozone, namely absorption efficiency of gaseous ozone, dissolved ozone concentration and ozone consumption. After establishing the model, we discussed the effect of concentration of gaseous ozone at inlet, temperature and organic compounds on dissolved ozone concentration.

국문 초록 (Abstract)

본 연구에서는 전산유체역학 기법을 통한 수리학적 모델과 오존 반응 모델과의 결합을 시도하였다. 오존 처리 공정의 모델링은 주입되는 오존(gas)과 원수(liquid)의 상(Phase)이 다르므로 오존과 물질간의 반응 모델만큼이나 접촉내부의 수리학적 거동을 모사하는 모델 또한 중요하다. 이에 본 연구에서 접촉내 수리학적 거동을 평가하기 위해서 전산유체역학 기법을 도입하였다. 대상으로 한 실규모 오존 처리 공정은 3개의 접촉조로 구성되어 있으며, 전산유체역학 모사결과 각 접촉조에서 심한 난류가 발생되는 것으로 나타났다. 특히, 수표면에서는 주 흐름 반대 방향으로의 흐름이 나타나는 것으로 조사되었다. 전산유체역학 모사결과를 바탕으로 각 접촉조는 작은 셀(cell)로 대분하여 물질 수지식을 수립하였으며 이 식을 이용하여 각 접촉내 유효 체적을 도출하였다. 셀 간의 물질 수지는 문헌연구를 통해 조사된 반응 속도와 상수를 토대로 수립된 오존 반응식과 결합시켰으며, 본 모델의 검증을 위해 용존 오존 농도 예측값의 정확성을 평가하였다. 그 결과 본 연구에서 개발된 모델은 오존의 물질 수지, 용존 효율, 배가스 오존 농도, 잔류 오존 농도 및 액상 오존 소비량을 만족스럽게 예측할 수 있었으며, 이 모델을 이용하여 오존 소비량에 영향을 미치는 인자들을 논하였다.

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