Journal of Bio-Environment Control (생물환경조절학회지)

The Korean Society for Bio-Environment Control (한국생물환경조절학회)
권호 표지

Development of an Aerodynamic Simulation for Studying Microclimate of Plant Canopy in Greenhouse - (2) Development of CFD Model to Study the Effect of Tomato Plants on Internal Climate of Greenhouse -

공기유동해석을 통한 온실내 식물군 미기상 분석기술 개발 - (2)온실내 대기환경에 미치는 작물의 영향 분석을 위한 CFD 모델개발 -

  • Lee In-Bok (Rural Systems Engineering, Seoul National University) ;
  • Yun Nam-Kyu (Agricultural Structures Engineering, National Institute of Agricultural Engineering) ;
  • Boulard Thierry (National Institute of Agricultural Researches, France) ;
  • Roy Jean Claude (FEMTO-ST, CREST, University of Franche-Comte, France) ;
  • Lee Sung-Hyoun (Agricultural Structures Engineering, National Institute of Agricultural Engineering) ;
  • Kim Gyoeng-Won (Agricultural Structures Engineering, National Institute of Agricultural Engineering) ;
  • Hong Se-Woon (Rural Systems Engineering, Seoul National University) ;
  • Sung Si-Heung (Agricultural and Biosystems Engineering, Konkuk University)
  • 이인복 (서울대학교 농업생명과학대학 지역시스템공학) ;
  • 윤남규 (농촌진흥청 농업공학연구소 시설방제공학연구실) ;
  • ;
  • ;
  • 이성현 (농촌진흥청 농업공학연구소 시설방제공학연구실) ;
  • 김경원 (농촌진흥청 농업공학연구소 시설방제공학연구실) ;
  • 홍세운 (서울대학교 농업생명과학대학 지역시스템공학) ;
  • 성시흥 (건국대학교 자연과학대학 생물산업기계공학)
  • Published : 2006.12.30
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Abstract

The heterogeneity of crop transpiration is important to clearly understand the microclimate mechanisms and to efficiently handle the water resource in greenhouses. A computational fluid dynamic program (Fluent CFD version 6.2) was developed to study the internal climate and crop transpiration distributions of greenhouses. Additionally, the global solar radiation model and a crop heat exchange model were programmed together. Those models programmed using $C^{++}$ software were connected to the CFD main module using the user define function (UDF) technology. For the developed CFD validity, a field experiment was conducted at a $17{\times}6 m^2$ plastic-covered mechanically ventilated single-span greenhouse located at Pusan in Korea. The CFD internal distributions of air temperature, relative humidity, and air velocity at 1m height were validated against the experimental results. The CFD computed results were in close agreement with the measured distributions of the air temperature, relative humidity, and air velocity along the greenhouse. The averaged errors of their CFD computed results were 2.2%,2.1%, and 7.7%, respectively.

변화무쌍한 기상변화가 실험의 정확도에 미치는 영향을 최대한 줄일 수 있도록 강제환기식 온실에서 실험을 하였고, 또한 대체적으로 크지 않은 온실에서의 실험으로 인하여 CFD모델결과의 오차를 크게 줄일 수 있었다. CFD와 현장실험 결과를 비교하여 본 결과, 온실내 1m높이에서의 평균풍속이 각각 $0.42m{\cdot}s^{-1}$과 $0.39m{\cdot}s^{-1}$으로써 CFD의 지점별 오차 평균값은 7.7% 로 나타났다. Y8.5m 지점에서 가장 큰 오차가 발생하였는데, 최대 오차는 -53.8%로 나타났다. 이의 가장 큰 이유로는 온실 길이방향에서 중간지점인 Y8.5m에서 풍속이 매우 작았기 때문에 소숫점 2번째 자리의 차이라고 해도 큰 오차로 나타났다. 작물형상의 기하학적 복잡성이 매우 큰 것을 고려한다면 오차범위는 매우 양호한 것으로 판단된다. 온실내 1m높이에서 평균온도의 CFD 평균오차는 2.2%로 나타났고, 최대편차는 5.5%이었다. 온실내 바닥으로부터의 복사열 발생량의 차이로 인하여 온실내 동쪽 지역에 상대적으로 큰 오차가 발생하였다. 외기 상대습도가 44%일 때, CFD상대습도의 오차는 2.1%이었으며, 최대 오차는 -3.8%이었다. 식물군의 공기유동저항, 식물군의 수분 및 열평형 모델을 추가하여 보다 사실적인 CFD모델을 설계하였다. CFD 모델의 설계방법이 정립되었기 때문에, 추후에 온실내 다른 작물의 미기상 및 이의 온실내 기상에 미치는 영향 등을 정량적으로 분석할 수 있게 되었다. 또한 작물의 적정생육환경에 주요 대상이면서도 동시에 센서설치의 어려움 등으로 인하여 연구에 어려움이 많았던 작물군내 미기상을 연구할 수 있는 토대를 마련하였다.

Keywords

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