대한기계학회논문집B (Transactions of the Korean Society of Mechanical Engineers B)

  • 제39권11호
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  • Pages.861-869
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  • 2015
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  • 1226-4881(pISSN)
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  • 2288-5324(eISSN)
대한기계학회 (The Korean Society of Mechanical Engineers)
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원추형 유동층 연소기의 수력학적 특성 및 열전달에 항력 모델이 미치는 영향에 대한 연구

Effects of Drag Models on the Hydrodynamics and Heat Transfer in a Conical Fluidized Bed Combustor

  • 강승모 (부경대학교 소방공학과) ;
  • ;
  • 고동국 (전북대학교 대학원 기계공학과) ;
  • 박외철 (부경대학교 소방공학과) ;
  • 임익태 (전북대학교 기계설계공학부)
  • Kang, Seung Mo (Dept. of Fire-fighting Engineering, Pukyong Univ.) ;
  • Abdelmotalib, Hamada (Dept. of Mechanical Design Engineering, Chonbuk Nat'l Univ.) ;
  • Ko, Dong Guk (Dept. of Mechanical Engineering, Graduate School, Chonbuk Nat'l Univ.) ;
  • Park, Woe-Chul (Dept. of Fire-fighting Engineering, Pukyong Univ.) ;
  • Im, Ik-Tae (Dept. of Mechanical Design Engineering, Chonbuk Nat'l Univ.)
  • 투고 : 2015.04.06
  • 심사 : 2015.09.08
  • 발행 : 2015.11.01
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초록

본 연구에서는 서로 다른 항력 모델이 원추형 유동층 연소기 내의 수력학적 특성과 열전달 현상에 미치는 영향에 대해, 입자상 유동에 대한 분자운동론을 적용한 오일러-오일러 모델을 사용하여 수치 해석적으로 연구하였다. Gidaspow 항력 모델과 Syamlal-O'Brien 항력 모델에 대해 유입 공기의 속도와 입자의 크기를 변화시키면서 연소기 내의 압력강하나 베드 팽창률 및 벽과 베드 사이의 열전달 계수의 변화를 조사하였다. 그 결과 베드의 팽창률은 속도가 증가함에 따라 커졌으며 압력강하는 속도의 증가에 따라 감소하였다. 벽과 베드 사이의 열전달 계수는 유입 속도가 증가하면 증가하고 입자의 크기가 증가하면 감소하는 것으로 나타났다. 베드의 팽창률이나 압력 강하와 같은 수력학적 특성은 항력 모델에 큰 영향을 받지 않았으나 열전달 계수는 항력 모델에 따라 차이가 나타났다.

In this study, wall to bed heat transfer and hydrodynamic characteristics in a conical fluidized bed combustor was investigated using computational fluid dynamics method. A two-fluid Eulerian-Eulerian model was used with applying the kinetic theory for granular flow(KTGF). The effects of the two drag models, Gidaspow and the Syamlal-O'Brien model, different inlet velocities($1.4U_{mf}{\sim}4U_{mf}$) and different particle sizes on the hydrodynamics and heat transfer were studied. The results showed that the hydrodynamic characteristics such as bed expansion ratio and pressure drop were not affected significantly by the drag models. But the heat transfer coefficient was different for the two drag models, especially at lower gas inlet velocities and small particle sizes.

키워드

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