Journal of the Korea Organic Resources Recycling Association (유기물자원화)

Korea Organic Resources Recycling Association (유기성자원학회)
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Effect of Hydraulic Pressure on Bubble Dissolution Rate of Ejector Type Microbubble Generator

수압이 자흡식 마이크로버블 발생장치의 산소 용해율에 미치는 영향

  • Kim, Hyun-Sik (Department of Civil & Environmental Engineering, Incheon National University) ;
  • Lim, Ji-Young (Department of Civil & Environmental Engineering, Incheon National University) ;
  • Park, Soo-Young (Department of Civil & Environmental Engineering, Incheon National University) ;
  • Kim, Jin-Han (Department of Civil & Environmental Engineering, Incheon National University)
  • 김현식 (인천대학교 건설환경공학과) ;
  • 임지영 (인천대학교 건설환경공학과) ;
  • 박수영 (인천대학교 건설환경공학과) ;
  • 김진한 (인천대학교 건설환경공학과)
  • Received : 2017.03.29
  • Accepted : 2017.05.10
  • Published : 2017.06.30
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Abstract

This study was performed to estimate bubble dissolution rate by change of hydraulic pressure according to increase of water depth. Experimental results showed that airflow rate was decreased by increase of hydraulic pressure. Because the force which acts on outlet of nozzle was increased by increase of hydraulic pressure. Mass-transfer coefficient decreased with decreasing airflow rate and increasing effective volume due to increase of hydraulic pressure as water depth increased. On the contrary, as the water depth increased, the bubble dissolution rate was increased because longer residence time of microbubble which was generated by ejector type microbubble generator. However it was thought that if water depth for capacity of ejector type microbubble generator is excessively increasing, bubble dissolution rate would be reduced due to low airflow rate and mass-transfer coefficient. Therefore, it is importance to consider the water depth when operating ejector type microbubble generator.

본 연구에서는 자흡식 마이크로버블 발생장치를 운전함에 있어서 수심 변화에 의한 수압이 산소 용해율에 미치는 영향에 대하여 평가하였다. 연구결과, 흡입 공기량의 경우 수압이 증가할수록 노즐 토출부에 작용하는 힘의 증가로 감소하는 경향을 나타내었다. 산소전달계수는 수심이 증가할수록 수압 증가에 의한 흡입 공기량 감소와 반응조 용적의 증가로 감소하는 경향을 나타내었으나 수심이 증가할수록 자흡식 마이크로버블 발생장치에서 발생되는 마이크로버블의 체류시간이 증가하여 산소 용해율은 증가하는 경향을 나타내었다. 그러나 자흡식 마이크로버블 발생장치 용량에 대비하여 수심이 과도하게 깊을 경우 낮은 흡입 공기량 및 산소전달계수로 인하여 산소 용해율은 감소할 것으로 판단된다. 따라서 자흡식 마이크로버블 발생장치 운전 시 수압이 중요한 고려사항이 됨을 확인할 수 있었다.

Keywords

References

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