부분 열원을 갖는 사각채널에서의 대류열전달

이종붕 慶南大學校 附設 工業技術硏究所 1998 硏究論文集 Vol.15 No.2

공기가 사각채널을 유동할 때 채널의 하부에 부분 열원이 있는 경우에 대 하여 수치해석하여, 유동 및 대류열전달 특성을 구하였다. 특히, 층류흐름은 정상상태에서 Grashof수가 임계값에 이르면 주기적 영역으로 천이가 일어나고, 그 후 준주기적 변화 과정을 거쳐 혼돈적 상태로 변화하였다. The characteristics of flow and convection heat transfer were numerically analyzed for the case of three heat sources under the channel when the air flow the rectangular channel. The results of numerical calculation are followings. First, when the Grashof number reaches the critical value under steady state, laminar flow occurs transition in periodic region, and through the semi-periodic change it becomes chaos state. Second, the heat transfer increased as the increase of Grashof number and the decrease of Reynolds number, and the average Nusselt number increased rapidly when the transition occurred.

PIV기법을 이용한 정사각 실린더의 후류에 관한 실험적 연구

이종붕,장태현 한국마린엔지니어링학회 2004 한국마린엔지니어링학회지 Vol.28 No.1

An experimental study is performed turbulent flow behind a square cylinder by using 2-D PIV technique. The Reynolds number investigated are 10.000. 30.000 and 50,000. The mean velocity vector, time mean axial velocity turbulence intensity. kinetic energy and Reynolds shear stress behind the cylinder are measured, The numerical method used this study is a CFD code, STAR-CD. The numerical results are compared with these of experimental.

물성치변화를 고려한 2성분혼합기의 층류막상 강제대류응축에 관한 연구

이진,박인식,이종붕 慶南大學校 附設 工業技術硏究所 1998 硏究論文集 Vol.15 No.2

전물성치 변화를 고려한 2성분혼합기가 평판상을 유동할 경우에 대하여 수치해석하여 층류막상응축열전달 특성을 구하였다. 그리고 정물성치의 응축질량유속 및 벽면열유속의 대수식을 변물성치의 경우에도 사용할 수 있음을 확인하였다. From the numerical analysis for laminar film condensation in the flat plate considered for the variation of physical properties in the condensate and vapor boundary layer, the following results were obtained. (1) The velocity, temperature, and concentration distributions in the condensate and vapor boundary layer are obtained no significant difference between for variable physical properties and for constant ones. But those distributions ar shown large difference in the vapor boundary layer for higher ?? in the case of superheated vapors. (2) The equations of condensation mass flux and heat flux at cooling surface, can be used for not only constant physical properties but also variable ones. And the normalized concentration equation for constant physical properties can be applied for the normalized concentration equation.

試驗林의 營林計劃運營과 經營組織에 關한 硏究 : 林業機械訓練院의 試驗林을 中心으로 with respect to Experimental Forest of F.T.C.

林榮俊,李鍾鵬 尙志大學校 1997 論文集 Vol.18 No.-

The purpose of this study is to suggest basic data for improving the management of national forest in Korea by analyzing operational performances of working plan on the experimental forest of Forest Work Training Center and by comparing the management organization between the experimental forest and national forest. The results are as follows: 1. According to the result of forest survey for working plan, 80% of all forest stand were proved to be less than age class IV so it is seemed that too much importance was attached to the tending work, caring of young growth and natural stand etc. 2. In operating of working plan when analyzing comparably the plan and actual performances, establishment of forest resources showed 108% of high performance rate while log production dropped slightly to 66.6% because the forest work was not executed for the compartments and subcompartments having low productivity. Therefore, economic and technical factors in performing the forest work shall be fully considered at the time of making working plan. 3. It is proved that functional organization of divisional forest-office cannot be operated efficiently due to the frequent personal changes and excessive area assigned to the personels whereas in line and staff organization of experimental forest, field manager could exert so exclusive rights with power and responsibility that coherent forest management could be maintained, and could understand situation of local area easily. Therefor, it is seemed that applying line and staff organization is more effective in the experimental forest management. 4. It was proved that communications could be faster and the range of responsible management of field manager could be enlarged by simplifying the hierachy of the organization in the experimental forest management. 5. Comparing the area of the experimental forest assigned to field manager with the functional area to the divisional forest-office, the experimental forest was seemed to be more effective from the viewpoint of field survey in the planned working place and management control since the movement time of business trip is short and the area to be managed is small.

소나무 천연하종 갱신 시험사업 사례소개

이종붕 수문출판사 2004 숲과 문화 총서 Vol.12 No.-

水冷時 三角棒의 溫度分布

李鍾鵬 경북대학교 공과대학 1980 工大硏究誌 Vol.9 No.-

When it was cooled the triangular rod in water, theoretical temperature distributions and cooling curves were obtained by the finite difference method. They were compared theoretically when the triangular rod has a hole and has not a hole It was obtained more uniform temperature distribution and more short cooling time in case the triangular rod has a hole than in case which has not a hole.

球形 Shell에서 點熱源에 依한 溫度分布 : 第二報 非定常狀態일 때 Part 2. for unsteady state

李鍾鵬,劉甲鍾 경북대학교 공과대학 1979 工大硏究誌 Vol.8 No.-

The temperature distributions of a spherical shell due to a point heat source were studied by analytical approach and checked by experiment. The temperature of a point source varied with time as T=(τ)/(a+bτ). Physical properties of spherical shell and the heat transfer coefficient of outer surface were assumed to be uniform. The heat transfer equation for the system was solved by a finite difference method for the unsteady state condition. Temperature profiles of the spherical shell were measured by thermocouples and were compared with the calculated profiles. Agreement of the analytical and experimental results was good.

임계점 부근에 있어서 포화순증기의 층류강제대류응축열전달

이종붕 경남대학교 공업기술연구소 2000 硏究論文集 Vol.18 No.-

임계점 부근(T□ /T□= 0.990∼0.9998)에 있어서 이산화탄소증기의 평판상에서의 층류강제대류막상응축열전달에 관하여 수치적으로 재 계산하였다. T□ /T□ 〈0.998 영역에서 열전달계수는 대표물성치로 평가한 Fujii 와 Uehara식으로 상관할 수 있다. 기액계면에서 열유속 혹은 응축질량유속은 평균정압비열로 나타낸 상변화수로 표시할 수 있다. A numerical analysis is recalculated for laminar forced convection condensation of saturated vapor of carbon dioxide on a flat surface in the reduced temperature range T□/T□ = 0.990 ∼0.9998. The heat transfer coefficient in the region T□ /T□〈0.998 can be correlated by using Fujii and Uehara's equation when the representative physical properties are evalulated at the film temperature. The reduction of the condensation mass flux or the heat flux at the vapor-liquid interface due to the convection term in the condensate film is expressed as a function of the phase change number with the average isobaric specific heat.

순증기의 자연대류층류막상응축에 있어서 액채막의 물성치평가온도

이종붕 경남대학교 신소재연구소 1994 論文集 Vol.4 No.-

물, 에타놀 및 프로판의 포화중기가 연직평판상에서 자유대류층류막상응축하는 경우에 대해서 수치해석하여 다음과 같은 결론을 얻었다. (1) 전물성치의 온도의존성을 고려한 경우 및 정물성치의 경우에 있어서 기액계면 열유속과 벽면열유속과의 비는 식(38)로 표시된다. (2) 액체막내의 대류열전달에 의한 Nusselt식의 보정은 식(44)으로 표시된다. (3) 점성계수만의 온도의존성을 고려한 해석에 의해서, Fujii의 근사해에 의한 무차원평가온도을 확인하였다. (4) Nusselt식에 r_(T)=1/4의 물성치를 채용하면, 실용적으로 약 2% 이하의 오차로 벽면열유속을 예측할 수 있다. The boundary layer equations for free-convection laminar film condensation of pure vapors of water, ethanol and propane on a vertical surface are numerically solved for the cases of constant properties, variable relevant physical properties. The conclusions are follows: 1) The ratio of the heat flux at the vapor-liquid interface to that at the cooling surface is expressed by ◁그림참조▷ (2) The correction for Nusselt's equation due to the thermal convection effect is roughly estimated by ◁그림참조▷ (3) The dimensionless reference temperature r_(T) derived from Fujii's aproximate analysis has been confirmed by the numerical results for the case of variable viscosity. (4) The Nusselt's equation evaluated by the physical properties at r_(T)=1/4 predicts heat flux at the cooling surface within an error of two percent.

水冷時 四角捧의 熱傳達係數

李鍾鵬,權永斗 慶北大學校 1979 論文集 Vol.28 No.-

When the rectangular rod was rapidly cooled in water, the average heat transfer coefficient was studied. Theoretical results ware compared with experimental results and it was obtained that the average heat transfer coefficient was equal to 6,000kcal/㎡hr℃. It has been already investigated that the average heat transfer coefficient for cylinder becomes 5,000kcal/㎡hr℃. The average heat transfer coefficient of rectangular rod was different from that of cylinder. Therefore the shape of cooling specimens had a great influence on heat transfer coefficient.