垂直西角空洞內의 空氣層의 自然對流에 관한 硏究

Abstract

本 論文은 두 境界面이 서로 다른 온도로 일정하게 유지되는 密閉된 直四角空洞內의 空氣層의 自然對流에 관한 연구로써 數値的方法과 實驗을 通하여 解析하였다. 間隔比의 변화와 Grashof數의 변화가 空洞內의 열전달에 미치는 효과를 분석하였으며 특히 여러 流動段階에 대한 定性的인 분석이 수치해석을 통하여 세밀하게 이루어졌다. 수치해석과 실험을 통한 Nud數, Grd數 및 간격비 사이의 관계식이 최종적으로 다음과 같이 각각 제시되었다.

수치해석결과 : Nu=0.255Gr(L/D)-0.224

10≤Gr≤10

2≤L/D≤40

실 험 결 과 : Nu=0.249Gr(L/D)

5×10≤Gr≤4×10

4.94≤L/D≤60.24

Laminar natural convection in an air layar contained in a vertically rectangular cavity with isothermal side walls at different temperatures has been investigated numerically and experimentally. It has been described what effect is reflected on heat transfer as the Grashof number and the aspect ratio are changed. Especially, the velocity profile, the temperature profile, and the isotherm configuration were analyzed with the various flow-regimes through the numerical method. Two Nusselt-Grashof correlations were presented using the numerical and the experiment, respectively as follows ;

Numerically : Nu=0.255Gr(L/D)-0.224

10≤Gr≤10

2≤L/D≤40

Experimentally : Nu=0.249Gr(L/D)

5×10≤Gr≤4×10

4.94≤L/D≤60.24

Laminar natural convection in an air layar contained in a vertically rectangular cavity with isothermal side walls at different temperatures has been investigated numerically and experimentally. It has been described what effect is reflected on heat transfer as the Grashof number and the aspect ratio are changed. Especially, the velocity profile, the temperature profile, and the isotherm configuration were analyzed with the various flow-regimes through the numerical method. Two Nusselt-Grashof correlations were presented using the numerical and the experiment, respectively as follows ;

Numerically : Nu=0.255Gr(L/D)-0.224

10≤Gr≤10

2≤L/D≤40

Experimentally : Nu=0.249Gr(L/D)

5×10≤Gr≤4×10

4.94≤L/D≤60.24